My wife is crazy. Help me convince her.

If the car is garage-kept, I doubt you will even see benefit in early morning start-ups.

 

My opinion is you will see a benefit. I do, and also have a very short commute to work. You may not need to run it 3 hours to get the benefit though, since you are starting out at a higher temp than I am. (Tonight is supposed to get down into the single digits)

 

Ebh?

 

Engine block heater.

There will still be some benefit. The 140F that the EBH can potentially provide is considerably warmer than, say, 70F (which I assume is about the highest anyone would heat their garage to). I've seen improvement in the first five minutes of driving even in the summer.

Rxmxsh, especially given your short commutes, I think it would serve you well. And if you need more ammunition to refute questions #1 and #2, I adamantly agree the answers are "No!"

 

I agree with Jim, had you included in your OP the fact that you have a very short commute, the initial answers may have been different. I think it will help you mileage if you only have a short commute. It should bump that first 5 min. bar up from 20-25 mpg to 40-50 mpg. Over the course of a tank, that can made a substantial difference, esp. with short commutes.

 

Please! He's from Southern California! Any commute over 100 ft requires a car.

Signed,
A former Northern Californian

 

Hey, I resemble that remark.
Seriously, such a short commute is hardly worth breaking into a sweat for. By the time you've changed into and out of the lycra, you may as well walk.

 

First of all, welcome to marriage .

Secondly, I was crunching some numbers recently, and an engine block heater, with current gas prices, and an increase in the first 5 minutes of driving from 25 mpg to 40 mpg at an average distance of 3 miles, will only pay for the cost of the green energy it uses (if bought at $4.50 / 100 kWh) vs. the cost of the additional gas used at $3/gal for the first 3 miles.

Additionally, the EBH, if plugged in for say 3 hours, and if a 1000W heater, will require twice the amount of energy be used than from the additional consumed gasoline for the first 3 miles- so you're really doing the environment worse as far as CO2 emissions.

Sure, if it's green energy, you can argue that no CO2 was produced, but w/ our energy infrastructure currently limited, that green energy should be used elsewhere.

JMHO as an engineer.

 

It's 400W.

 

Thanks, I wasnt sure. I'll look at the numbers this evening on my spreadsheet- but it looks like cost- which was I think $0.14 per 3 hour heater run (or fuel cost) would decrease by the equivalent, or 2/5 of 14 cents. At that rate, energy use should be almost equivalent also, so pick your poison.

...Alternatively, It'd really be great to have a cat converter heater.

 

Tell wife no, no and yes.

I'm in So. Cal and almost exact as you. Garaged (but no insulation or even drywall) and commute almost the same. I drive 12 miles each way, about 10-15 min. I have seen an improvement in mpg since the install. I have my EBH on a timer to turn it on just 3 hours before I leave for work. BTW I'll be blocking my upper grill this week until the weather warms up. Just because we don't have extreme cold and snow doesn't mean we can't benefit from some of the cold weather tricks others use.

 

Looks like:
block heater nrg analysis
127000000 J/gal gasoline

without heater
3miles for warmup
25mpg for warmup
0.12gal gas for warmup
15240000 J fuel energy for warmup

with heater
3miles for warmup
40mpg for warmup
0.075gal gas for warmup
9525000J fuel energy for warmup

fuel nrg savings 5715000J

Block heater nrg input
3no hours
400W block heater
4320000block heater nrg

xtra energy used by block heater-1395000
** a power plant at ~70% efficiency will also emit more CO2 than this energy lets on.j

...so, it looks like you could come out ahead.