I'm a bit puzzled by this. An electric water kettle that consumes about 2 KW will boil a quart of water in about three minutes. With 400 watts you might boil a quart in about 15 minutes. Running such a heater for 2 1/2 hours is a lot of heat. I hope you're not boiling your engine oil every morning.

2006 HCH Alabaster Silver w/Navi
2003 Honda Accord LX

Elan,
I'm not sure what the capacity of the coolant system is, I'd have to look it up, bu t you make a good point. I'll have to re-run my test - it's been awhile. As I recall it was pulling 3.33 amps at 120 volts, but it's possible I read the ammeter wrong.

The most I've ever seen from the temp gauge when starting after using it was two bars, so I'm sure it's not getting that hot. And the block heater is mounted in the bottom of the engine, so it will certainly circulate the coolant.

As I said, I'll double check the reading. Thanks.

Don't forget too that the engine block and drive train is dissipating a lot of that heat. That's a lot of metal to keep warm.

True. As the temperature rises you reach a point of equilibrium with the heat dissipation. The question is, how high is the temperature at equilibrium. Also, if you reach that point within half an hour, let's say, then the next two hours of heating are wasted energy.

2006 HCH Alabaster Silver w/Navi
2003 Honda Accord LX

That all depends on the outside temperature. Growing up in Minesota, you leave the car plugged in all night and it never reaches any equilibrium. It gets disipated nearly as fast as it pumps in. But if you don't leave it plugged in all night it will take hours to warm it up in the morning.

Yeah, you're right, and it doesn't make sense to run it longer than needed. Obviously, as zimbop says, it will depend on outside temp. I have noticed that the engine cools down very quickly when parked, which says that the heat dissipation is probably pretty high. I paid attention back in February. One cold day I parked for 5 minutes to run into a store. When I came back out my temp gauge was already back down to one bar.

I've been journaling to see if shorter amounts of time give me similar results in initial rpm, how quickly my FCD seems to respond, and when I get first AS - the latter two being difficult to gage. But with the weather changing rapidly I quit doing that and will have to wait 'til next fall to get good data.

I just double-checked the amperage draw for the Honda block heater - 3.27 amps at 120 volts. Looks like 400 watts is probably correct on the nominal rating.

I also did a little experimenting. I believe 2-3 hours in 40 degree temp is about right to bring the engine temp up about as high as it will go. When I pre-warm the engine, I the FCD begins to "work" a lot sooner, if you know what I mean. Without pre-heat I have to drive about a half mile before I start getting reasonable readings on the FCD. With pre-heat I get it almost immediately.

I have def. noticed this as well. It leads me to believ that our car has at least
aluminum heads and possibly an aluminum block. Cast iron heads and block retain the heat much better however, they are alot heavier. We benefit from the lightweight but the heat reduction does not help us. If only there was a way to wrap a 'blanket' around the engine block to keep it warm with out having to pay an electricity bill to keep it warm.

....as a side note: in the past when racing cars, the older engines (with a cast iron block) really hold in the heat which causes a loss in power, even after racing just a quarter mile. Many of times you would have found me and others putting huge bags of ice on the engine block to help cool down the motor before the next race. Now, I am trying to keep the engine warm; funny.

Interesting aftermarket idea. The Engine Blanket. I'd probably be crazy enough to buy one and use it!!

We use our hybrid for a short commute daily, about 5 km each way. In the winter (in Halifax) the mileage is around 8 l / 100 km, but now that it has warmed up we are in the the 6.5 l / 100 km and getting better daily. We look forward to the summer.

I have received several emails along the lines of "whats wrong with your car, take it to the dealer, ...learn to drive, ..pump up the tires", etc. Folks there is nothing the matter with the car, short trips on a cold engine kill the mileage; longer trips in this car achieve the same mileage as everyone else gets.

Remember this car replaces one which used 17 l / 100 km under the same conditions.