Small block heater to keep warm instead of warmup
 

I think my title says most of it. I have a 2000 Honda Insight with a manual transmission. It certainly doesn't disappoint in the economy department, as I am averaging about 70 mpg since the weather warmed up. Unfortunately, I was fighting to get 60 during the winter. Granted, that amount to less than $9 per month in extra gas, but I was fighting for 60, and it took a lot of the fun out of driving it. I think I would have better luck with a block heater. I was wondering if anyone had tried to use a low power block heater to maintain heat instead of using a 800 watt heater to heat it up. My guess would be that a smaller one wouldn't be able to hold a big enough temperature differential, but I thought I could pass the thought on to someone who understands the thermodynamics a lot better than I do.

I think you'd have better luck with grill blocks and insulating the engine rather than spending energy trying to gain energy efficiency. The 2nd is always MUCH harder to do.

I did some ABABABAB testing of a block heater vs MPG driving to work. The electrical energy to the block heater was equal to or greater than the fuel saved. The best setting was to turn on the heater about two hours before leaving for work.

So I stopped using it.

Your car may respond differently. Run some tests and tell us the results.

block heater and/or a tank heater [heats the coolant/radiator fluid]in a cold climate is not a bad idea from the engines view point. i use a block heater if its below 10 F .
not for any fuel savings but because warm oil flows better , reduces engine wear at start up , puts less strain on an already weak battery at cold temps. lets the engine get to operating temps faster and the cabin heat works faster,,

my ford came with a block heater installed from factory.. really nice at Zero or 20 below

Might find homeless people sleeping in it if you park over a ventilation grate,
so scratch that..

I vote larger heater used over a smaller time frame. Less loss to atmosphere than small over long.

So then no one has tried it. I doubt I will either; I thought the same thing as you but thought it was interesting enough to bounce off someone else. I did a grill block last year and that helped; I couldn't even keep the engine fully warmed up without it. This year I will do a better block as well as a hot air intake. I am still leaning towards a block heater because I doubt it takes as long to warm up the Insight's 1.0 L engine, 2.6 quarts of oil, etc. as a more teaditional auto. Even if it is energy neutral I will get a warmed car with less wear on internal parts, as well as fewer stops at the gas station. Plus I won't be freezing by butt off.

A lot of Prius owners use them in the colder states. It can make quite a difference if your morning commute is cold enough. Between the block heater and grille blocking I'm sure you'll see a gain. Now whether this enough to offset the electricity use or not is another issue. It's sort of like the plug-in hybrid debate as to which is cleaner as well but the idea that it may make your winter commutes more satisfying could trump every other concern.

What about a solar oven to heat it up, ok maybe not the most practical, and if you get up and use the car before the sun comes up then would be pointless. But in some cases where one gets up after the sun comes up and has a parking spot facing the rising sun with a homemade solar oven capturing the heat and directing it up towards the engine? Brainstorming here so might not even be doable.

I think im going to try a small block heater for this purpose, would be much easier to plug it in and leave it. If I use a 50watt heater ill use less than $4 a month in electricity.