warming up the car vs. engine block heater

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.

 

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.

 

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

 

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.

 

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

 

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.

 

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.

 

so far it appears to be a wash whether to install a block heater or not. Interesting.

 

Think of it this way:
This is the Prius.
If this item made a real impact on efficiency for a reasonable percentage of owners, it would be standard equipment.

 

and you probably wouldn't have to plug it in.

 

I plan on keeping the car way more than 2 years. I usually drive them into the ground or give them to my kids and that is the same thing. We have cheep power and mostly hydro so it is cleaner, at least as far as our air is concerned. Also the power is made here and not from imported oil. Lots of balancing to be done here between several factors. The “right†answer may be different for different people. Also I am willing to bet gas will go up not down. Now what I need is a smart timer that measures the outside temp and starts the block heater at the correct time depending on the weather! I have an old PB 140 I wonder?

 

this morning I was going out so pluged in the block heater and let it run for 25 minutes went out and with the OAT at 10C the miniscanner said ICE was 24C which is within a couple of degrees of where the 2k4 would be with the thermos and no block heater. That 25 minutes cost me about 1 1/2 cent worth of electricity (we pay .0618 cents per KW) against 95 cents per liter for gas The block heater was installed by the dealer if prep for sale of the car when new. I'm now on my third winter of using it and at 350 watts I doubt that it's lifetime will be short more like the life of the car as are most block heaters even in cold climates. Again I say if your burning gas and not moving your mileage is going down.

 

well around here, electricity is cheap and the same price 24/7 but there was a seminar on AER (all electric range) Priuses here and using the base of 6.5/KWH the same distance AFTER accounting for conversion losses gave a price of 70 cents per gallon.

now that is charging a battery, so the conversion will be much different for block heater. i guess in extremely high areas, it would be close to break even. but around here, its a win-win situation. interesting to nail down a cost range for a break even point. if it is 20 cents as one suggests, i would think that that would be obtainable nearly every where. no one pays more than that do they?

 

And if you add electricity, it's not quite honest to claim the increase in MPG without citing the electricity and component costs as well.

 

those of us that use hydro for electricity don't necessairly have a "longer tailpipe" as all the refineries use electricity to crack oil to gas so you have to include it in the tailpipe as well. I spend about $7 a month extra on electricity and that buys me about 1 1/2 US gallons of gas and gives me about 127 extra miles to a tank of gas in the winter. Can you go 127 miles on a gallon and a half?

 

Using the EBH as part of the warm-up contributes to better air quality. When the ICE is off there are no emissions. Prius is an AT-PZEV, take advantage of the design, don't idle. Use of the EBH conserves fuel, air quality and prolongs oil life and effectiveness.