warming up the car vs. engine block heater

[JackDodge]

I'm planning on getting an engine block heater sooner or later but I got the car out of the garage and had to go retrieve the trash bin. Then I remembered something that I needed that was still in the house and went and got it. It occurred to me when I got back behind the wheel that the engine block had a good headstart in warming up before I got on the road so I wonder, does idling the car in the morning before leaving do the same job as an engine block heater? I mean, it costs something in gasoline but the heater would cost something in electricity so wouldn't idling be a good alternative? When I'd been on the road for a few minutes, I noticed that the mileage hadn't dropped several tenths of a mile as it usually does. That it was right where it was when I got home last night.

[Frank Hudon]

well you've burnt gas and gone nowhere, so your mileage is down. How much depends but it's still down. I don't let the car idle for any reason. Costs nothing to restart it so that's what I do.

[tomdeimos]

During warmup you can travel at 0 mph or up to around 35 mph or more all for the same amount of gasoline. So the faster you go without burning more gas the better your mpg.

In addition, if you go up to highway speeds so the gas burn rate goes up too, then the warm up will be over with much faster, and you save even more.

[Three60guy]

Yes BUT....

JackDodge was asking about the relative difference in COST between using electricity to warm up the engine via the Engine Block Heater and using gasoline to do exactly the same thing.

There are actually two questions here.

1.) How long does it take the engine to warm up from say 32 degrees (outside temp)

2.) How long does it take the Block Heater to warm up the engine from the same 32 degree point? (outside temp)

Once we know this we can calculate the difference in COST. Sure there will be a hit to the miles per gallon but there will also be a hit in your pocket book to heat up the Block heater too.

Which one is cheaper?

People who have Block Heaters please raise your hands. Please tell us about how long it takes you to heat up those engines.

Everyone else, how long does it take to see good mileage figures on your MFD? For my newbie eyes it is only taking 5 minutes. And that is just going out and driving it. So, if we only take 5 minutes to warm up the engine would that work too?

Inquiring minds would like to know. Ok, so who is first? lol

[efusco]

There is a ton of info in the LONG block heater thread including power use, cost/benefit ratio, emissions benefits, etc. There's no need to try to repeat that here.

[Three60guy]

That thread is way too big just to answer a simple bottom line question. Yes, if one wants to read all of that fine but cant we have a readers digest version here? I have read that entire thread and still don't know the answer to JackDodges question. Try seeing this through the eyes of typical users instead of an administrator. No offense intended, just constructive input.

[Tideland Prius]

Not only that, it'll depend on when the last time your car was shut off. That'll depend on how hot your coolant in the thermos is.

[Kiloran]

Originally posted by Tideland Prius@Jan 6 2006, 01:29 PM
Not only that, it'll depend on when the last time your car was shut off. That'll depend on how hot your coolant in the thermos is.

[snapback]184821[/snapback]

Presumably, that would be the same with or without the EBH.

[tomdeimos]

This has been covered, and depends on your electric rates. Costs in New England are high.

But again:

3 hrs of block heat at 350 w is around 1 kw hr.
Cost in electricity is in the 10 to 20 cents range here.

For this cost I get well over 5 mpg better on my morning commute.
This is around 10% or more gas savings.

Gas at $2 a gallon gives a cost savings of 20 cents

So worst case I break even.

In actual costs I save a lot, because my electricity is nearer the 10 cents end with my time of use rate,
and I also only need the full 3 hours when it gets down toward 0 deg F. Most of the winter
1 hour or 1 1/2 hours is plenty of block heater time.

[Kiloran]

Originally posted by tomdeimos@Jan 6 2006, 01:38 PM
This has been covered, and depends on your electric rates.     Costs in New England are high.

But again:

3 hrs of block heat at 350 w is around 1 kw hr.
Cost in electricity is in the 10 to 20 cents range here.

For this cost I get well over 5 mpg better on my morning commute.
This is around 10% or more gas savings.

Gas at $2 a gallon  gives a cost savings of 20 cents

So worst case I break even.

In actual costs I save a lot, because my electricity is nearer the 10 cents end with my time of use rate,
and I also only need the full 3 hours when it gets down toward 0 deg F.   Most of the winter
1 hour or 1 1/2 hours is plenty of block heater time.

[snapback]184830[/snapback]

Missing from this calculation is the cost of the EBH, ~$60.
If it lasts 2 years, this increases the daily cost by ~$0.09.
The EBH may actually end up more expensive but I'd expect the cost difference is probably a wash for most people.

[Edit] Corrected my grammar after reading. :P