Should I Buy a Telsa Solar Roof?

Tesla just started taking orders on their Solar Roof today.   Is it a good deal as promised?

You can get details on the solar roof along with a quote on the price for your house at the Tesla Solar Roof website.    Plugging in the numbers there myself for our house I get :

Cost of roof  = $45,100
Tax cred = -$10,700
Value of Energy = $27,400
Net cost over 30 years $7000

They make it look good that way.    But what you're really doing is spending $34,400 today to get $27,400 energy over 30 years.   Thats not so good of a deal.

But theres more.     My state and local utility also offer incentives that combined would cut another $8800 off the price.   That gets the net cost of front down to $25,600.    This is a much better deal but I still don't want to spend $25,600 today for $27,400 spread over 30 years.

Really a Solar Roof is going to be best if you're already looking at the cost of replacing a warn out old roof.   Our own home has a very new roof.    So it doesn't make sense to tear off a perfectly good roof to put on a Solar Roof.    We do have a rental property that we replaced the roof on not too long ago for about $7200.    If you figure in the cost of that $7200 roof then going with a Solar Roof instead starts to make more sense.   Youre not looking at spending $25,600 today for $27,400 over 30 years.  Instead you're looking at spending $7200 for a regular asphalt tile roof or getting the Solar Roof for $25,600 along with $27,400 in energy.   Thats really a cost of $18,400 for the energy.   Now you're getting closer.   But its still not really worth it.

The thing that would really make a Solar Roof worth while is comparing it to a more expensive roof.   When I replaced that rental roof we got traditional asphalt shingles as you see on the majority of roofs (at least around here).     However the Solar Roof is a higher quality glass material.   Its more comparable to glass tile roofs or slate shingles.    Those higher quality materials cost a lot more.   Using those materials would cost 2-3 times as much as the asphalt roof.   If you're now comparing a solar roof to a roof that is $10,000 to $20,000 then thats a different equation.     Bloomberg has a graphic comparing roof costs in their article Tesla’s Solar Roof Pricing Is Cheap Enough to Catch Fire

The situation where it makes sense then is replacing a worn out old roof with a new higher end material roof.    If the net cost of a Solar Roof is $25,600 and the comparable alternative is a $20,000 slate roof then you're really looking at spending $5,600 more to get the solar power.   That solar power adds up to $27,400 over 30 years.   The power savings starts at about $600/yr.    The net present value of the 30 years worth of power is over $13,000.     So you're spending $5,600 more net to get the solar power saving $600 a year with a total value of $13,00.    Now that makes sense.

So while I would not run out tear off my perfectly good roof tomorrow for a Solar Roof, it could very well be worth getting one if you have an old roof that needs replacement and you were looking to use higher end materials.

One last point to make is that the Solar Roof has a "infinity warranty".   They warranty it forever the life of the house.   So you won't have to replace the roof out of pocket.    Now I'm not sure how much thats really worth, I didn't look at the details.   But that certainly does add value over traditional roof materials which need replacement.     But a cheapo asphalt shingle roof should last 30 years and a nice slate roof should last 50 to 200 years.   Slate roofs may as well be "forever" as far as most of us would plan.   But the lifetime warranty isn't nothing.

Bottom line:   Tesla Solar Roofs can be a good financial choice in the right situation.   If you're looking at replacing an old roof with a higher end roof it can be a good deal.   It all depends on the specifics.

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How Wasteful Is It to Leave The Fridge Door Open

Whenever I see the refrigerator door left open for too long I can almost feel my blood pressure go up.    I react like someone has attached a vacuum hose to my wallet and is sucking $20 bills out of it.    I don't really know why I have such a automatic negative reaction to an open fridge door.   Maybe my parents drilled it into me as a child growing up or maybe I just have a instinctual dislike for what I consider wastefulness.   But turns out its really not all that bad.

I looked at several sources and it seems the consensus agreement is that  leaving the fridge door open a little while too long doesn't waste much energy to be concerned about.

A Reddit thread discussed the topic a while ago.   Someone there did the math to calculate the energy it requires to cool down the air that escapes when you open a fridge door for 20 seconds.  They concluded that it takes "0.0002 USD to heat all that air".    

The Portland General electric utility did a study on wasteful fridge use.  
"It turns that if you never opened the door, they would use about half the annual projected energy consumption listed on the familiar yellow EnergyGuide cards"
They measured how much energy is used by keeping a door open different amounts of time from 5 seconds up to 10 minutes.   Unfortunately (and very annoyingly) they didn't label the actual values so they've just got unlabeled bar graphics.    At least they confirmed that the longer the door is open the more it uses.    But I can't easily tell if its even directly proportional or not.   I zoomed into their graphic using paint and then added gridlines to count the unit height of the bars.   Seems the usage per time isn't proportional.  I figure it roughly :

seconds	energy
5	1
10	2
30	2.5
60	3.5
120	6.5
300	20
600	29

They also look at opening and closing the door two times versus leaving the door open for a longer period to see if its better or worse to open and close when you get an item and return it or just leave it open the whole time.

They concluded its better to open and close twice than to leave it open based on their measurements.   Suppose though that it depends on how long you take.   If it only took you 30 seconds total that would be less energy than if you opened and closed for two 10 second intervals based on their data from how much energy it takes to leave a door open a specific period.

Michaelbluejay.com says that :
"Home Energy magazine says door openings account for 7% of fridge energy use, assuming 42 door openings a day.  But the Institute of Food & Agricultural Sciences at the University of Florida (link no longer available) says poor open/close habits waste 50 to 120kWh a year, which would be 10-24% of a 500 kWh/yr. fridge.  They don't say whether this is too-frequent opening, or leaving open too long when opening, or both."

But that seems to contradict what Portland General said when they concluded that half of the energy use is when you never open the door.

So we've got anywhere from 7% to 50% of usage based on opening/closing the door.   That variation may be due to the changes in fridge design.   Maybe as they've gotten more and more efficient they require less energy to remain cold when the door is cold so now opening/closing the door uses up more of the consumption versus the past.  Just a theory.

A Phys.org article Energy mythbusting: The truth about those energy-saving tips cites research from a Michael Blasnik saying :

"the moment you open the door, the cooled air rushes out, and it's a fairly trivial loss, he said. Most of the refrigerator's coldness is held not by the air but by the contents, and those contents won't warm up significantly in the time it takes you to decide between the leftover pizza and last night's meatloaf.
Obviously, leaving the door open all the time would waste energy, because your refrigerator would never stop running, Blasnik said. But closing the refrigerator door quickly will save you a dollar's worth of power a year at most, his research shows."

If we assume that worst case 50% number then thats a few bucks  month.   A full size 24' cubic fridge uses about $90 a year.   Half that is $45 a year.   Thats 12¢ a day roughly.   People open and close their fridge probably a couple dozen times in a day and total usage there is probably more like 1/2¢ per door opening/closing.    If I assume that this is a normalish 10s period and then use the chart Portland General made then we could guess it wastes maybe another 1/2¢ to leave a fridge door open a full minute instead.

Ideally I'd really like to measure it myself by using a kill-a-watt meter to measure actual usage for leaving a door open varying times like Portland General did.   But I don't have the ability to do that easily.  I'm not going to mess with our fridge at home like that just out of curiosity.   Suppose it won't do any real harm but it just isn't convenient.  Maybe next time I have a rental vacant I can do some testing, but that would be an empty fridge and may not be valid comparison.

No matter how I cut it, best or worst case scenario we're talking in the order of anywhere from $1 to $20 a year in total cost from someone leaving fridge doors open for longer periods of time.   It could be as little as 0.02¢ to leave a fridge open 20 seconds to 1/2¢ to leave a fridge open for a full minute.

It of course adds up over time and its not good to leave a fridge open for long periods without reason.   But leaving a fridge open for a minute or so really only costs a fraction of a cent worst case.  Its nothing for me to get bent out of shape about.

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Is a Tesla Powerwall Worth Buying Just To Avoid Paying Peak Electricity Rates?

Tesla recently announced a home battery system called Powerwall.       One of the selling points they made was :

"Avoid Paying Peak Rates Power companies often charge a higher price for electricity during peak evening hours than overnight when demand is low. Powerwall can reduce your power bill by storing electricity when rates are low and powering your home when rates are high"

That intgrigued me.     If you're not familiar with the idea of peak rates, this is how it works.   Electric companies may have a rate system setup that charges you a higher cost during peak rates and a lower cost during off peak rates.   They may do this to try and shift usage off peak and even out their loads better.   For example a utility might have a normal base rate of 10¢ per kWh but if you have the peak rate system then they charge you 15¢ during peak and 5¢ in off peak.      If you had a battery you could charge the battery at night for 5¢ and then use the power during the day and basically save yourself 5¢ per kWh versus the normal rates.


Would a Tesla Powerwall pay for itself simply by shifting your electricity usage to off peak times? 

The Powerwall comes in 2 models a 10kWH unit and a 7.7 kWh model.    The 10kWh version is for weekly cycle and apparently more for emergency backup.   The 7.7kWh model has a daily cycle.    They run $3000 for the daily 7.7 and $3500 for the weekly 10.    We'd be looking at he 7.7kWh model for daily use at $3000.    These costs do not include an inverter or installation.   I'll ignore those costs for now and get back to that later.

The 7.7 kWh daily cycle Powerwall costs $3000.    It has a 10 year warranty.   They also mention a 10 year extension.   If I used 7.7 kWh every day for 10 years then that would be a total of 28,105 kWh.      With a $3000 cost that comes to about 10.7¢ per kWh based on a 10 year life.   Lets assume a 20 year life to be generous for the battery.   That gets us down to 5.3¢ per kWh cost for the battery alone. 

If your off peak energy costs more than 5¢ kWh more than on peak then this is getting close to feasible.    However you'd also have the costs of the installation and possibly a AC-DC inverter too.    I don't know what those cost.     I believe that home PV solar systems will have a AC-DC inverter in them but I"m not sure if that is what you need for the Power wall exactly.    I'd take a wild guess that installation will run you $500-$1000.   But thats really just a wild guess.

I'm going to conclude that a Powerwall isn't financially practical for most people just to avoid paying off peak power rates.      I suppose if you have particularly high difference between peak and off peak rates it might make sense but from what I see a max 5¢ difference between normal charges and off peak seems typical.   But my numbers still assume a 20 year life for the battery and I haven't calculated in the installation costs.    You might need to see more like 10-15¢ per kWh between peak and normal to make these practical just to save off peak electricity charges.

Bottom Line : NO I really don't think that a Powerwall is worth it financially just to take advantage of low off peak electricity rates.

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How Do Solar Panels Impact Home Value?

I've looked at solar panels on and off and still haven't pulled the trigger to buy them.   When I've evaluated the benefit in the past I've not placed any value in the panels themselves.  I figured they were just going to be used up and depreciate in value until they are broken and thrown away in 20 or more years.   But that is actually ignoring some good value in panels.   Solar panels should increase the value of a home.   I mean if you're looking at two identical homes and one has a solar panel on it then I'd certainly pay more for the house with the panels. 

If I assume a panel will save you $1 in electricity over 20 years then I would calculate the net present value of that at about $18.36.   I could then add that value to the value of the house.  If the panels are older and maybe only have say 10 years left in their life then I'd cut the value in half.

I found a couple sources giving what they say the added value is :

Costofsolar.com said:

"The National Renewable Energy Laboratory* offers a useful guide when determining how much your property’s value will go up. According to its research, each additional $1 in energy bill savings (from your solar installation) adds $20 to your home’s total value." 
*They had a link to the study but that link is now dead.

An NY Times article from 2011 said:
"The premium ranged from $3.90 to $6.40 per watt of capacity, but tended most often to be about $5.50 per watt."

 Those are different measures.  One is looking at savings to your energy bill and the other is looking at Watts capacity for the panels.   How do they relate?    You'd have to look the amount of sun you get locally to figure that.   In my area I figure roughly that one W of capacity gives me about 30¢ a year in electricity savings.   Of course it will be more or less depending on how much sun you get.

But if I do the math then the NYT source is saying that most often the value is $5.5 per watt.   If one W saves you $0.30 in electricity then that relates to valuing $1 of electricity savings at about $18.33.   Almost exactly the same as my $18.36 NPV guess. 

I think the right way is to determine the energy savings and then figure what thats worth.


Personally I think those estimates are a bit high.   Or at least they seem to really be only looking at brand new panels.   I can see spending that kind of money for a brand new panel but not an older one.


Note that I'm only talking about panels you own outright.   An NPR article pointed out that leased panels can be a negative.   People don't understand the leased system and you don't actually own those panels.  

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Should I Throw Away Two Light Bulbs?

We have four small recessed lights in the ceiling of our hall.    Originally all four were incandescent bulbs.   They when I used up the last of my remaining incandescents I shopped around for replacements.   The incandescent bulbs were around $3-4 each.   I found LEDs for $10 each and decided to try one.   I bought one Sylvania 6-Watt R20 Medium Base LED Flood and it worked fine.    So then I bought 3 more to eventually replace them all with LEDs.    Another bulb burned out so I now have 2 LEDs and 2 incandescent.

The lights in question are in a main hall so they're on most of the time.   I figure an average of 10 hours a day almost all year.   We'll ball park it at 350 days a year.   Thats 3500 hours of use annually.  Could very well be less than that but I'm just estimating here.   If I replace the 35W incandescents with the 6W LEDs then I'll save 29W each.    That comes out to about roughly 100 kWh a year or $10 in annual savings.    

I haven't yet replaced the two remaining incandescent bulbs because I'm waiting for them to burn out before I replace them.    It just seems a waste to remove a working bulb like that.  

The LEDs are rated for 25,000 hours of use.    The incandescent bulbs are expected to last just 2500 hours.   I think I'm getting longer life out of the incandescents but can't say for sure.  

Lets look at the cost of the bulbs in 100 hour chunks: 

There are two components to the cost.   The cost to buy the bulbs and the cost of the electricity to operate them.

Cost to buy :
LED = $10 / 25000 = 4¢ / 100 hr
incandescent = $3 / 2500 = 12¢ / 100hr

Cost to operate :
LED = 6W * 10¢ kWH = 6¢ / 100hr
incandescent = 35W * 10¢ kWH = 35¢ / 100hr

If I was at the store comparing these two options then there would be no contest.    The LED wins hands down.  It costs 10¢ / 100 hr vs 47¢ for the incandescent.

However I have a partially used incandescent installed right now and my decision is between : option A) leave the LED on the shelf and continue to use the incandescent and option B) remove and throw away the partially used incandescent and install the LED in its place.

The electricity cost is clear.    Option A will cost me 35¢ and Option B will cost 6¢.

How I account for the cost to buy the bulbs in Option A versus Option B isn't clear to me.  For some reason I can't seem to wrap my head around this.   I've already bought both bulbs so that money is spent and its a sunk cost.   But if I use one or the other bulb it will save me buying another bulb which is minimum 6¢ /100hr to operate.  Huh?   I've confused myself.   Maybe a helpful reader can help me untangle this. 

In any case no matter how I cut it I'm pretty sure the 35¢ /100hr electricity cost of running the incandescents outweighs everything else.   Say I figure that throwing away the incandescent is wasting 12¢ for the incandescent bulb and then using the LED costs me 4¢ for the cost to buy that plus the 6¢ in electricity.  Add that all up and throwing away the incandescent and using the LED instead comes out to 22¢ total.   But continuing to pay electricity for the incandescent is 35¢.   So I seem to be spending a minimum of 13¢ / 100 hr to continue to operate those incandescent bulbs.

Bottom Line : yes I should throw away two light bulbs

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Is a Natural Gas Fueled Car a Good Idea?

In a recent article T.Boone Pickens said we should use natural gas cars more.   I agree in general.   Natural gas is more abundant and cheaper here in the USA than oil.   It doesn't require refining and is pumped straight to most homes.  Natural gas burns cleaner than gasoline too.

Apparently the only natural gas car out there is the Honda Civic GX.   They cost $25-30k which is about the same as a Civic Hybrid.     However the natural gas car should save you around $200-500 a year in fuel if you drive 15,000 miles a year.    There is also apparently a Ford F-150 truck option for CNG/LNG but thats a new option and I don't see as much on it.  They do say that tanks would cost $6000 to $9000 which I think would mostly make that kill that as far as cost effectiveness.

There are some state level tax incentives as well.  Apparently 20 states have some sort of incentive.   You can find it your state has incentives here.  Oklahoma gives 10% of vehicle cost up to $1500.   Texas rebates $2500.   Pennsylvania has a $1000 rebate.   I'm not sure about the details on the tax credits or rebates so you'd want to research that on your own.

How much you save with natural gas will vary though based on the cost of natural gas in your area.  The average price of natural gas nationally  is about $1 per therm for residential rates..   The natural gas equivalent to a gallon is about 1.14 therms.   So on average the cost is $1.14 for natural gas equivalent to a gallon of gasoline.      Natural gas prices vary across the nation.    The EIA tracks natural gas price data by state.  Its over $4 per therm in Hawaii and under $0.80 per therm in Colorado.

Prices at public fueling stations seem to be more than home prices.  Public stations tend to range around $1.50 to $2.50 a gallon.   A map of prices is here.

Honda does not recommend home refueling according to the  Civic GX owners manual.    "Due to the wide variation of natural gas quality for home use, Honda does not recommend the use of home refueling at this time"    I don't know if home refueling hardware does a good job of ensuring the gas is filtered properly or not.   If you did fuel at home you'd have to buy the refueling hardware and have it installed.  That can be as much as $6000 total bill.

Public CNG stations are limited.   This is a major draw back to natural gas cars and a key reason we don't see more of them.  But that makes ita  chicken-vs-egg situation.   There aren't enough refueling stations to drive demand for cars but lack of cars doesn't give incentive to open more refueling stations.   The Honda GX has only about 8 gasoline gallon fuel capacity and  mileage of 27 city/ 38 highway, so you can only drive around 200-300 miles.   
  
There is a map on the EIA site.   I captured their map below.

Source : EIA

Note the light red sites are private so only the dark red locations are of use to the general public.
Theres large sections of the nation with no refueling locations at all.  Looks like South Dakota doesn't have a single refueling station.   You'd have a hard time driving from Seattle to anywhere else I'd imagine given the lack of public stations outside the Puget Sound.   But refueling at your home exclusively would probably work just fine for most people.    A 200 mile local driving range is more than enough for anything but longer distance day trips.

Overall I like the idea of natural gas fueled cars and they can make sense.  Its cheaper to operate than a gas based car and some states have tax rebates to boot.    If you're looking at a Honda Civic or similar size car then the natural gas based Civic GX might be worth a look.  But I'd definitely make sure the finances make sense.  If you have to buy a home fueling station then that extra cost can make CNG car more expensive overall even with cheaper home natural gas.


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Spending $7 a Year on a TV I Don't Use

About six years ago now I wrote about saving money with a smart power strip.    One of the details in that article was "The 19" TV uses 8 watts while off."     I've still got that 19" TV.   We don't really use it.  But its been moved to another location and is no longer plugged into that smart power strip.   So it sits there doing nothing day after day collecting dust.   Its almost always plugged in because .. well I'm just lazy or forgetful and don't remember to flip off the power strip on/off button.   My wife occasionally watches DVDs on it as well so she might turn it on once in a great while.  Though I can't recall when she watched one down on that TV.   We've got a 55" TV in our media room so theres little reason for watching a movie on the 19" TV.

That 19" ancient CRT I've had for around 20 years now is costing me about $7 a year in electricity while its off.    8 watts power usage while off is going to add up to about $7 in electricity for a year.

8 watts x 24 hours in a day x 365 days = 70,080 Watt hrs x 10¢ per kWh = $7

I should really get rid of that old TV.  Or at least unplug it.


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Are Solar Panels a Good Investment? (3rd look)

Apparently its been four years since I took my 2nd look at solar panels.    I've heard lately that the cost of solar panels has dropped so I'm looking again.

A calculator  [dead] at FindSolar.com to get a rough estimate of the cost and savings.   They use a cost of $6 per W for the solar installation.


I figured the costs at $4.5 / W and then figured the federal, local and utility incentives myself.   I used a local calculator to figure my electricity savings.   The results for me are :

KW	system cost	incentives	NET	elect save	ROI
1.5	$6,750	$5,925	$825	$217	26%
2	$9,000	$7,900	$1,100	$289	26%
2.5	$11,250	$9,875	$1,375	$361	26%
3	$13,500	$11,850	$1,650	$433	26%
3.5	$15,750	$13,175	$2,575	$506	20%
4	$18,000	$14,200	$3,800	$578	15%
5	$22,500	$16,250	$6,250	$723	12%
6	$27,000	$18,300	$8,700	$867	10%

One of the local incentives has a maximum pay out so the returns max out at about 3 KW installation for me.    A lot of the incentives we get locally are not available to most people.  My state and local utility are pretty generous with the incentives.   If you only get the 30% federal tax credit then your ROI would work out to only about 3.4%.  


For me at least in my area it seems solar installations are definitely now worth it financially.    Of course the math differs depending on local incentives from your state or utility.    If you don't have generous state or utility incentives then the ROI may turn out to be just 3.4% range which isn't a great investment.

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Affordable Electric Cars

Electric cars are starting to get affordable.

Photo credit mariordo59

A search on Edmunds shows 4 electric car models under $30,000.   However all 4 are in the sub compact class so they're small cars.   If you're looking at cars in that class then an electric might make sense.   The electric versions have limited driving range but its enough to meet the needs of most people for local city driving.

Here are the four cheapest electric cars and their base MSRP:

Mitsubishi i-MiEV = $22,995
Smart fortwo Electric = $25,000
Chevy Spark EV = $26,685
Nissan Leaf = $28,980

(note that some cars may not be available nationwide, I didn't check)

If you then also get the full $7,500 federal tax credit for EV's then that makes the cars fairly affordable.  You do have to have $7,500 in taxes paid for the year to get the full credit since the credit is non refundable.   But a lot of people don't pay that much in taxes to the IRS so they would not get the full $7,500 in credit.

	MSRP	w/credit
iMiEV	$22,995	$15,495
fortwo	$25,000	$17,500
Spark	$26,685	$19,185
Leaf	$28,980	$21,480

These prices are getting more affordable but they still aren't nearly as cheap as similarly equipped gas cars.    


The fortwo and Spark have gas equivalents so I can do a rough comparison of costs to buy and pay for fuel between the gas and electric models.

	Spark EV	Spark gas	fortwo EV	fortwo gas
Cost	$19,185	$12,858	$17,500	$13,270
12 payments	$4,140	$2,772	$3,780	$2,866
Fuel	$307	$1,200	$278	$1,167
annual	$4,447	$3,972	$4,058	$4,033

In both cases the annual cost is higher for the electric cars if we just look at making payments and fuel costs.     My estimates are based on driving 12,000 miles a year, paying 10¢ per kWh and $3.50 for gas.     I also figured just making payments and financing over 5 years on 3% loan.  Of course you could pay cash up front and then figure the opportunity cost.

Given that the electric cars should have higher resale value and lower maintenance costs I'd give the edge to the electric models in both cases.  If you happen to live in one of the states like Georgia or Colorado with Colorado with generous tax incentives then it can be a no brainer to get the electric.


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How Much Does It Cost To Leave Our Door Open in The Winter?

I have some frugal habits that are pretty ingrained in my personality.    One of the habits is not to leave the door open when its cold outside.   Sometimes I see people who do not always close a door quickly when it is cold out.    Anytime anyone has a door open for longer than a few minutes in the winter I start to get uncomfortable about it.      And 'uncomfortable' is the right word to use too, it kind of makes me a little upset to be honest.  Its almost as if someone just lit a $10 bill on fire for no reason.   But it has occurred to me that I don't really know how much heat this wastes.   I mean I know it wastes heat, that much is common sense, but I don't know HOW MUCH heat is wasted.  

There are frugal things that I do and don't do based specifically on how much they cost.   So if I"m going to get upset about an wasteful habit then I should really at least have an idea of how wasteful it is.   I mean if it wastes $1 in heat every time someone does this and they do it every other day then that is $15 wasted heat a month.   But if it only wastes 0.1¢ then I'm getting upset about nothing really.   So the actual cost is pretty important to keep things in perspective. 

I couldn't think of a good way to calculate the heat wasted on my own.   I searched Google and came up with a site that had done the math   (I'm not sure if that information is from Questline or Rocky Mountain Power or both).    They figured the amount of air that would move over an 8x10 opening based on different inside and outside temperatures.   I'll look at the example for 40F outside temperature since I live in the fairly mild Northwest US and that is a more common winter temperature average for us.

Their figures are based on natural gas at $1.20 a therm and an 80% efficient heater.    Our heat is a bit cheaper than that actually I figured that our heat would be about 75% of their costs.    So when they figure that an open 8x10 door would cost $1.88 an hour our cost would be more like $1.41.   Furthermore they are using an 8x10 door and our door is only about 3' x 8'.   Our door is only about 30% as large.   The $1.41 cost for a 8x10 door would be proportional to a 42¢ /hr cost for our 3x8 door.    Translate that into a per minute cost and you're looking at 0.7¢ per minute for our front door and our heating system.

Bottom Line : It probably costs only about 1¢ per minute to leave our front door open.

That seems surprisingly low to me.   Is this right?   Did I make a math error?    I'm seriously asking... Assuming its right, then thats not nearly as bad as I'd have thought.

This actually helps me feel better about it.   I am not going to get all bent out of shape if someone occasionally wastes a couple pennies by lingering at the front door.   

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Is Online Shopping Bad for the Environment?

This time of year we've been getting a lot of packages delivered to our house through online shopping and other people shipping us gifts.   Ok to be honest we're always getting lots of packages delivered since we do most of our shopping online nowadays taking advantage of stuff like Amazon Subscribe and Save and other online discounts.   Its convenient to have things delivered to our door.   But I have wondered if those UPS and Fedex trucks driving all around might be wasting a lot of gas.

My initial assumption was that it had to be more efficient for delivery trucks to run routes than for everyone to make individual trips to stores.  

Lets say a truck holds 100 packages and makes 50 stops in its route.   Each individual stop in the route only adds a small incremental amount to the total trip distance.  You might go a couple blocks out of the way to add a house or even have stops fall in between other stops.   The delivery companies will certainly do their best to optimize the trips because they know that saves them gas which improves their profits.   If you took the same 100 packages and had 50 individual people go and get them from a local store you'd have 50 round trips to stores which is certainly many extra miles of wasted gas and time.   

I confirmed my hunch not too long ago when I read about this study on the topic:

Grocery delivery service is greener than driving to the store
They say :
"University of Washington engineers have found that using a grocery delivery service can cut carbon dioxide emissions by at least half when compared with individual household trips to the store."

They have a couple graphics on their site that illustrate the kind of thing that happens in the example I gave.

I looked around a little more to find other sources. 

I also found another study Carnegie Mellon Study Finds Shopping Online Results in Less Environmental Impact

and they say :
"A new study by Carnegie Mellon University's Green Design Institute found that shopping online via Buy.com's e-commerce model reduces environmental impact with 35 percent less energy consumption and carbon dioxide emissions than what is produced in the traditional retail shopping model."


Thats two academic resports that support the claim that online shopping is actually more efficient.

I have confidence that the answer is that online shopping isn't bad for the environment and in fact saves gas over individuals making separate trips to local stores.

--This article may contain referral links which pay this site a commission for purchases made at the sites.

Shopping Around for Cheap Gas - Don't Forget Your Time

The other day I was running out of gas and had to stop to fill up.  I usually try to find the cheap option for gas so I had a decision to make.   I know in general which stations are cheap in my area and I stick to those as much as possible.  I had two cheap options in mind.  I could either swing into the grocery store and use their gas station or I could drive a little further and go to Costco.   Usually the Costco is a little cheaper so I figured I could save some money going to Costco.   But the Costco was a bit further out of my way.   The grocery store however was really right on my way and was only a quick stop off the normal track.

I decided to go ahead and just stop at the grocery store.    I figured yes maybe Costco was a little cheaper but driving out of my way might very well cost me more in gas just to make the side trip.  

Was I right?

After the fact I calculated the actual distance I'd have to drive for both trips.  

Driving out of my way to swing by Costco would have taken an extra 2 miles.    My car averages about 22MPG so that 2 miles would have been 1 / 11 of a gallon or 0.09 gallon.    At Costco gas was running $3.10.   So driving those extra 2 miles to Costco would have used 28.2¢ more worth of gas to get there.


Gas at the Costco was running 4¢ per gallon cheaper than my grocery store station.   I filled up with 14.6 gallons so I spent $0.58 more at my grocery store station than I'd have spent at Costco. 

If I had driven to Costco I would have spent 28¢ worth of gas to drive the extra 2 miles but I would have saved 58¢ to fill up there.   That would have been a net difference of 30¢ cheaper at Costco.

Net cost difference : Costco would have been 30¢ less.

No I wasn't correct.  Driving out of the way to Costco would have saved me money even after figuring in the cost of gas to drive the extra 2 miles.

But what about my TIME? ...

When I made the decision to just stop at the grocery store I didn't consciously figure in the waste of time to drive down to Costco.    I didn't stop and think "my time is worth more than that".   My decision was just about "this gas is more expensive, but I'd waste gas to get to the cheaper option".    But I really should have considered the amount of time taken in the equation too.


Driving out of my way down to Costco would have also taken 5 minutes longer.  

 Is 5 minutes worth 30¢ to me?     I'd say yes.  That figures to just $3.60 per hour.   I have a lot better things I could be doing with my time than saving $3.60 an hour.   Even if you figure in taxes thats still below minimum wage level.

Now can I simply cash in 5 minutes of time and get 30¢?    Not really.   5 minute increments of time are hard to cash in.   But if you do this stuff often enough it adds up.   Don't think of it as just 5 minutes that would have been wasted otherwise.   Little bits of time like 5 minutes add up and if you save enough time you get an hour and then with an hour you can really put it to a better use.   Better uses for your time dont' necessarily mean working an extra hour at your job and getting paid an extra hours worth of wages.   I might instead use that hour towards some other money saving frugal tactics.

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Considering Energy Use When Shopping for a TV

While browsing at Costco I notice that most of the TVs now seem to show their energy usage guide.   The numbers don't seem very high and are usually around $25 a year ballpark.   It seems like a pretty small figure compared to spending $500-$1000 on a TV.    However the amount of electricity used by TVs should not be ignored when comparing models.   If you add up the electricity cost over a 5 year lifespan the differences between models can be significant. 

To illustrate the point I grabbed the retail prices and electricity costs for a few TV models off the BestBuy website.   I then figured the NPV (Net Present Value) of purchasing the TV at the advertised price and the energy consumption over a 5 year period.   I used an arbitrary 4% discount rate for NPV.

Here is a selection of 55" TVs :

Brand	Tech	Retail	Energy	NPV
Insignia	LCD	$600	$47	($786)
Haier	LED	$649	$24	($731)
TCL	LED	$700	$15.5	($742)
Vizio	LED	$800	$16	($840)

The LCD based Insignia model is the cheapest to buy at just $600.   However if you figure in 5 years worth of electricity costs then the LED based Haier model is cheaper in the long run.   Another detail to notice is that between 3 different m manufacturers we see a fairly significant spread of energy costs among the LED models.   The costs ranged from $15.5 to $24 per year for the same size and technology.   You can see a pretty large difference in energy use between brands.  

And here are some 50" TVs:

Brand	Tech	Retail	Energy	NPV
Panasonic	Plasma	$500	$26	($597)
TCL	LED	$530	$10	($554)
Insignia	LCD	$550	$39.00	($702)

In this case again an LED model has the lowest NPV but not the lowest Retail price.    The plasma from Panasonic is cheaper to buy but has higher electric use.

In both examples I looked at buying the cheapest TV would result in higher overall costs once you figure in the cost of electricity.

Keep in mind these are just examples to illustrate the point.   You may do better overall with a bargain sale price on a Plasma model.   But the point is to look at both the initial purchase price cost of buying the  TV as well as considering the long term energy usage costs.

It should be pointed out that the energy guide figures are based on 11¢ kWh electricity rates and 5 hours of daily usage.   Your electricity cost and viewing habits are likely to vary so you should probably adjust the figures to match.

Bottom Line:   Don't ignore the energy consumption for large screen TVs.   Paying a little more for a more energy efficient model can save you in the long run.
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Better Planning on Driving Can Save Lots of Gas Money

This past weekend my wife and I took a trip to a store to buy an item that was on sale.  This trip ended up being 11 miles each way for a total of 22 miles round trip.   Thats about 1 gallon of gas for my car.    In total the trip cost us roughly $3.50 worth of gas at todays prices.  The store in question is on my way to work from our house.   If I had instead stopped there on my way home from work on Monday then it would have been just 0.6 miles out of my way.  That would have cost me about 10¢ in gas.   This extra trip cost us about $3.40 in gas.    It wasn't that big of a deal, it was just one trip and my wife was anxious to buy get the sale item in question before they sold out.   The sale was $50 off of an item that rarely goes on sale so theoretically getting there soon may have saved us $50. 

But what if we engaged in such trips routinely?    If we failed to plan our trips to the store like that and went there just once a month we'd be wasting $42 a year at todays gas prices.

There are two stores I often go to for groceries.   If I go to both in one trip then the total trip from home to store A to store B to home is 12.3 miles.   If I were to make two separate trips then I'd spend 9.1 miles to go to store A and 10.6 miles to go to store B.   Thats 19.7 miles total.   By combining the stores into one trip I save 7.4 miles.   That costs about $1.17 in gasoline for my car.   If I did that once a week for the weekly grocery trips then that would add up to over $60 a year.

Now lets say that my wife and I got home from that trip to the store and later decided to go out to eat for dinner.   If we didn't plan it well and went to the store in the afternoon then made a separate trip to eat out in the evening then we would have wasted more gas.  It is 6.7 miles round trip to the restaurant from our house.   Add that to the 22 miles round trip to the store and you've got 28.7 miles total.     If we'd instead gone to the store first and then the restaurant then the total would be 20.6 miles.   Thats a difference of 8.1 miles or about $1.28 in gas.   

Some of this may seem like common sense to most of us.   Of course you'll save money and time if you combine trips.   But on the other hand maybe its not so obvious how much you can save.  Its also not as easy to plan in advance unless you're really thinking about it.   Say my wife and I had gone out to dinner after that trip to the store, combining those trips isn't something I'd necessarily think ahead to do on a random Saturday afternoon.  But if you're aware of the fact that any given trip might cost you $2 or $3 extra in gasoline then you may be more likely to think ahead and combine all your trips as much as possible.

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LED Light Bulbs Now Cheaper than CFLs in Long Run

For quite a while LED bulbs have been too expensive to warrant the purchase and not really cost effective over CFLs.   When I looked at LED light bulbs last spring I concluded that LED bulbs were still too expensive.   At that point the LED bulb I looked at was 'under $19'     But today that same bulb is $16.09.   As I assumed in that article over time prices for LED bulbs are coming down.   There are also LED bulbs cheaper than that in the $11 range depending on size and application.   With LED prices coming down I decided to take another look and see how they compare to CFLs (compact fluorescent lamps).   

I'll look at three different applications.   To compare the costs I'll first just add up the cost of the bulbs and the cost of electricity assuming 10¢ per kWh.  I'll also then do a NPV (net present value) comparison.  I will ignore inflation so this isn't a perfect analysis but good enough to get a basic idea of the numbers.

First lets look at a standard 60W equivalent bulb 


CFL :GE 13-Watt Energy SmartTM - 8 Pack - 60 watt replacement
Cost : $1.49, Watts : 13, Life : 8,000 hr
LED :Lighting EVER 7W A19 LED Bulb, High Performance Samsung LED, Daylight White, 60W Incandescent Bulb Replacement
Cost : $10.88, Watts : 7 : Life : 30,000 hr

To make the math a little easier lets assume 7500 life on the CFL and assume you need 4 of them to last as long as the LED.

CFL : 4 bulbs x $1.49 +  30000 hr x 13 W / 1000 kW/W x $0.10 kWh = $44.96
LED : 1 bulb x $10.88 + 30000 hr x 7 W / 1000 kW/W x $0.10 kWh = $31.88

Now I also did a NPV calculation assuming 4% discount rate and came out with NPV of $26.89 for the LED and $35.35 for the CFLs.    This is because you're spending more of the money today with the LED so its not quite as favorable when you look at present versus future costs of money.   But I did a simple figure and didn't account for inflation of electricity or bulb costs so its not perfect.

Lets compare candelabra bulbs.

CFL :GE Cfl Candelabra Bulb (00373)
Cost $6.75, Watts 5, Lifetime 6000 hrs

LED : 2 Pack Ge 1.8-watt Led Candelabra Base 75-lumen Decorative Bent Tip Light Bulb, Clear
Cost : $14.55, Watts 1.8, Lifetime 12000 hrs

If you want 12,000 of light then you can buy 2 x CFL or 1 x LED.   Total costs would be :

CFL : 2 bulbs x $6.75 + 12000 hours x 5 watts / 1000 kw/W x $0.10 /kWh = $19.50
LED = 1 bulb x $14.55 + 12000 hr x 1.8 W / 1000 kw/W x $0.1 /kWh = $16.71

For this example the LED is cheaper in total cost.

NPV would be $15.68 for the LED and $16.31 for the CFLs.   LED still wins.

Now let us compare flood lights for recessed can lighting

CFL :GE Energy Smart CFL 72984 15-Watt, 750-Lumen R30 Floodlight Bulb with Medium Base, 2-Pack
Cost : $7.99, Watts 15 : lifetime : 10,000
LED : LED Light Bulb, 900 Lumen, Warm White, 9 Watt (65W Replacement) by G7 Power 
Cost : $16.09, Watts : 9, lifetime : 30,000 hr

CFL = 3x $7.99 + 30,000 hr x 15W / 1000 W/kW X $0.10 kWh = $68.97
LED : 16.09 + 30000 hr x 9W / 1000 x 0.1 = $43.09

NPV numbers are $52.54 for the CFL and $35.48 for the LED.

Note these bulbs are not exactly the same in shape and size.  However the LED specs. claim its a replacement for recessed lighting and R20 size bulbs.  It will be a little smaller than the CFL version, but I couldn't find a direct equivalent CFL to LED for this application.

In both cases the LED's are cheaper over the life of the bulbs.

In all three cases I looked at here the LED comes out on top.   However if you change any details then the CFLs could easily be cheaper, it still depends on the specifics.   It seems if you are willing to take the leap to LEDs then it is worth it financially.    I think I'll still wait on buying LEDs until they're a little more proven.   They claim long lifetimes and I expect thats realistic given LED technology but I think I'd like to wait and make sure the technology is proven.   Plus if I wait a little longer I expect LED prices will drop even further.
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One Lease I'd Take : $69 /Month Electric Car

I normally don't think leasing a car is a good idea.   The Autoblog site ran a story about a dealer in Illinois that was advertising a $69 per month 24 month lease deal with $2100 in fees on the Mitsubishi i-MiEV.   : Mitsubishi i available for just $69 a month in this outrageous lease  I visited the site of the actual dealer O'Brien Mitsubishi but I see no $69 lease advertised there.   Its possible they already sold them out and removed the deal, I have no idea.

In any case if I had the opportunity to lease a car for $69 a month I think I'd do that in a heartbeat.  Especially if it was an electric car.   Lets say you just commute 25 miles round trip to work and your car gets 25 MPH which is relatively common situation.   That means you spend about 1 gallon in gasoline per work day.    That alone equates to about $70 in gasoline per month.   Once you add in the cost of depreciation on the car it makes even more sense to get a $69 lease.   Of course you do have to pay for the electricity but thats significantly cheaper than the gas.   Also that $2100 in up front fees is a hefty sum.  But all in all this would be a pretty great lease deal if you were looking for a good daily commuter option.    Now on the other hand a reasonably good mileage older used car would still possibly be a cheaper option overall.



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Finally A Cheap Electric Car : Mitsubishi's i-MiEV

Thus far electric cars have not been particularly cheap or ultimately practical financially.  Chevy Volts cost about $40,000 and the Nissan Leaf is about $35,000.   Even with the hefty $7,500 federal tax credit the electric cars have not been especially cheap to buy. 

Mitsubishi has a new electric model named the i-MiEV.   MSRP on the iMiEV is $29,125.    After the $7,500 tax credit you end up paying $21,625.  [edit: Clearly 'cheap' is a relative term.   I've never paid over $15,000 for a car myself, but as far as new cars go and cost efficient cars like electrics, this is cheap.]

When you figure in the savings on fuel the i-MiEV becomes very practical.    The TCO cited by Yahoo is just $25,547 for 5 years.    They don't seem to say, but I think the TCO figures in the price after the federal tax credit.

The $25,547 TCO for the Mitsubishi i-MiEV makes it one of the cheapest cars to operate.   In fact it might be the cheapest new car on the market in terms of TCO compared to all gasoline, electric and hybrids.




I found a list of best TCO cars from Kelly Blue Book.  They have the Nissan Versa as the cheapest TCO coming in over $29,000.     If anyone knows of a cheaper TCO new car, let me know but I can't find one. 

Of course you can do better with used cars but I'm trying to compare apples to apples.  I like to buy used cars myself and I recommend it as a good frugal tactic.   If you wait a few years you might find a good deal on a used electric i-MiEV.   But these are brand new models so I can only compare to new to new.


State incentives
In addition to the federal $7500 credit there are also various states that also have more rebates or tax incentives.    Some state incentives are minimal like waiving your license fee or emission testing but some states have large credits.  Colorado residents are apparently eligible for up to $6000 or $7500 tax credit.   Georgia,  Illinois, New Jersey, and Utah have state credits ranging from $3000 to $5000.

Other costs
On the down side, I don't think the TCO figures in cost to install a 240V charger.    Most people will probably want a 240V charging station in their house if possible.    The 120V charger takes about 22 hours to charge the car and the 240V charger takes only 7 hours.    The charging station costs about $1000 plus installation.    Also, I believe the TCO figure would assume a national average electricity cost of 11-12¢ per kWh.  Mitsubishi's FAQ says it will cost about $3.60 to go 100 miles assuming 12¢ per kWh.   If your electricity is much more or less then that will impact your costs and the TCO.

Don't Worry about battery life

One of the common complaints or worries about electric cars is the lifespan and replacement cost of the battery.   Its reasonable to worry about battery life and costs.   But generally with hybrids and electric cars the concerns over battery life is full of misinformation, myth and confusion.   The battery in the i-MiEV is backed by a 8 year / 100,000 mile warranty.   That means that even if there is a premature problem it will be covered by Mitsubishi.   And the fact they are giving such a long warranty is clear evidence that the battery should last.  

Its a Small car
The car is a smaller car and does not have a lot of interior space.   It is also limited range vehicle and Mitsubishi claims a range of 62 miles but of course that kind of thing varies depending on use. Edmunds has a full review  of the i-MiEV.  They say they could only get it up to 82 MPH on the freeway.   Thats well above the speed limit but if thats the maximum speed it may be difficult to get it up to freeway speeds.    The size and power seem much more suited for city use.    This car is clearly not to everyone's tastes and needs, but for a lot of people looking for a practical and cheap car that doesn't guzzle gasoline the i-MiEV may suit your needs.

I'm glad to finally see an electric car that is practical financially.   I personally like the idea electric cars and hope to see more Americans buying them so we can reduce our dependency on foreign oil.   I'm not in the market for a car myself so I won't be buying one.    I also have to be honest that I don't know if I'd buy such a small car, but I'd at least consider it as a 2nd commuter car to supplement a full size family car to share between my wife and myself.


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Do Automatic or Manual Transmissions get Better MPG?

It used to be that manual transmissions were the hands down winner for better fuel economy.   However this is no longer the case.   Modern automatic transmissions are more and more efficient.   Todays automatic transmissions can even provide better gas mileage than a manual version.

There is no clear cut winner.   Depending on the make/model of vehicle its possible that either the automatic or the manual transmission could provide the better gas mileage.

Here's just a couple examples.   I looked up the cars in question on the government Fueleconomy.gov website.   Below are screen captures of the results.   First the Chevy Sonic is one car where the manual transmission has better efficiency.

On the other hand for the Honda Civic the automatic transmission is better.

You can no longer assume that a manual transmission will provide better mileage.  It really depends on the vehicle in question.
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LED Bulbs are Still Too Expensive

fivecentnickel recently asked Is it Time to Switch to LED Lightbulbs?  My answer to that question is 'no'.

In short, LED bulbs are still to expensive.  Nickel pointed to one bulb for sale on Amazon with a cost of $32.99 (+6.99 shipping).  It claims to last 50 times as long as conventional lighting.    I found another bulb for under $19 (+2.5 ship).   That one has a lifetime guarantee.   Whether they cost $20, $30 or $40 thats still too expensive.

A typical CFL (Compact Fluorescent Lamp) can be bought for around $1-2 nowadays.   The CFLs last around 5-10 years. 

You could buy a 10 pack of CFL's for $10 or $20 and they would last you 50-100 years total.    On a cost per year basis the CFL is still cheaper than the LED even though the LEDs last several decades.

Theres another good reason to delay on buying a LED.  In the future the cost of LEDs is likely to drop further.  As the technology matures and they become more commonly used the prices will drop.   Its quite likely that in a few years LED prices will be well under $10 and may approach the cost of CFL's today.

LEDs may be a great technology but right now they simply cost too much.  
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Energy Costs versus House Age

Modern homes are built in more energy efficient ways.   New homes usually have better insulation, more energy efficient double pain windows, more efficient furnaces or air conditioners and other energy efficient improvements over older houses.   It then only stands to reason that newer homes should be cheaper to heat and cool. 

Of course newer homes are often larger than older homes so some of that efficiency gets masked by the higher energy costs of a larger home.   Therefore the best way to compare the energy efficiency based on age and improved building practices is by the average cost per square foot.

I found information on average energy spending per homes from the US Energy Information Administration and they broke it down into the decade the home was built.   The numbers are from 2005 which is the most recent covering this information.

Here's the data :

Year of Construction	$ / sq ft
Before 1940	0.88
1940 to 1949	0.88
1950 to 1959	0.86
1960 to 1969	0.90
1970 to 1979	0.89
1980 to 1989	0.85
1990 to 1999	0.76
2000 to 2005	0.68

Interestingly there aren't t major differences in the amount spent on the homes from 1940 to 1979.   It seems that the biggest efficiency improvements kicked in after the 1980's. 

If you were looking at a home built in the 1960's versus one built after 2000 then you could expect to see about a 24% decrease in average energy expenditures.

I should point out that this analysis is not perfect since this is just the amount people spent and not necessarily an indication of the different quality of home building per decade.   In other words its feasible that people who own older homes are more likely to waste energy or something like that.   I haven't proven a cause - effect here.   Also the data doesn't take into account other variables such as who owns the homes, where they are built, etc.  Its also possible that more of the new homes are built in states with lower energy costs.   However I think its pretty reasonable to take national spending averages and then assume that the differences are related to building practices based on building age.  

It should also be noted that these are just national averages and individual spending will vary greatly in different climates and other factors.    

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