Excellent list!
One more consideration - many vehicles run the AC compressor when the HVAC controls are set to defrost. Such vehicles would run the compressor more in winter than summer (here).
Interesting. I didn't realize this.
Excellent list!
One more consideration - many vehicles run the AC compressor when the HVAC controls are set to defrost. Such vehicles would run the compressor more in winter than summer (here).
Yep, good reason not to own a dodge, everything for the truck is cheap but the gas isn’t even with it moving under 1500 miles a year.That is a 46.7% drop in fuel economy.
I've estimated this based on data logging fuel consumption on a couple of different vehicles. Generally speaking, the electricity cost will be about the same as the fuel savings, if the block heater is used for 2-3 hours before driving. Shorter plug-in times are more efficient and economical than longer ones, and there's a greater benefit to fuel economy in colder weather.I wonder if anybody has done a calculation of the cost of running a block heater vs. the cost of the gas saved by using one. Of course it would depend on the price of electricity and the price of gas currently where you live, and also the ambient temperature, and your specific engine, but it would be really interesting to see.
It doesn't seem to be the case with our '07 Dodge Grand Caravan - I've used the ScanGauge to monitor the instantaneous fuel consumption at idle. It doesn't change when the selector is moved from any of the other settings to defrost. (If it did, I'd pull the AC fuse for the winter.)Interesting. I didn't realize this.
Just the fuel savings from using a block heater are huge.I wonder if anybody has done a calculation of the cost of running a block heater vs. the cost of the gas saved by using one. Of course it would depend on the price of electricity and the price of gas currently where you live, and also the ambient temperature, and your specific engine, but it would be really interesting to see.
Just the fuel savings from using a block heater are huge.
Some years ago I did a comparison, doing the same run when the engine started off cold (coolant temperature -20°C) vs. warmed by a block heater (c. +20°C). As I recall, the cold-start short trip (c. 8 km) yielded about 5 km/l (awkward format, but that's how the early ScanGauge presented gas mileage) and the pre-warmed trip was 8 km/l.
5 km/l works out to 20 l/100 km, whereas 8 km/l is 12.5 l/100 km.
To run the block heater 3 hours/trip for 12.5 short trips would result in 37.5 hours of block-heater usage (for 100 km of short trips). The block heater was 400 W, so at present prices would cost $0.04/hour to run.
Four cents per hour x 37.5 hours = $1.50.
Let's use the present cost of gasoline - $1.50/litre.
Without using the block heater, I'd use 20 l of gas = $30.
With the block heater I'd use 12.5 l = $18.75.
So over 100 km of short trips, block heater use would cost $1.50 in electricity but would save $11.25 in gasoline.
This is aside from reduced wear and tear on the engine, less fuel dilution of the oil, faster cabin heat, reduced wear on the starter, battery, and charging system ...
But do I use the block heater myself? Not often, because I park in an attached garage which doesn't get terribly cold, and there are too many horror stories of garage fires caused by block heaters.
Outside in cold weather, yes!
Yes, the engine would operate at lower throttle when the air is colder. This reduces engine efficiency since it increases pumping losses. The engine has to work harder to pump air through the throttle restriction.I'm trying to follow, but if a naturally aspirated engine produced more power in cold air, wouldn't you just let off the gas slightly to compensate and achieve the same speed? So why would you see a drop in MPG?
Thanks! I should have added that the advantage that a block heater provides is greater for short trips.This is great, thank you.