For the block heater type I looked at a few before calling Honda, just to see about cost. Decided to go with the Honda OEM, about $160 installed - not cheap but it's a nice setup, goes in the engine block coolant drain hole. Looked up specs on wattage and couldn't really find anything, and nothing in the owners manual. Initial thought was 3-4 hrs for time on the block heater, but sounds like it shouldn't take near that long. If instructions aren't provided by Honda will play with it and see what works - maybe 15 min or so and see how it does.
Block heater screenshot below.
View attachment 343075
I prefer the block mounted ones, and these today seem pretty quick - guessing that shroud may help convection circulation.
An hour might be enough - perhaps closer to 2 hrs at -40C. Assuming adequate coolant levels, left ON overnight should not be a problem (other than the utility bill, if paying) - an OE Honda heater should be tested for continuous duty use.
Using that heater for short trips this winter means that engine =
I haven't used one, but I'm pretty sure I've seen a block heater extension cord with a built in thermostat - nice for those nights that start out (Canuck) warm, then drop like crazy.
I went looking for an external cord, but found this instead, (Even better, as it senses the coolant hose temperature):
Temro Block Heater Extension Cord 5 Feet GM Chevrolet Accessory Part New | eBay
Purchased new at GM parts counter for block heater, GM accessory part.
Made in Canada by Temro, Part Number 2900009.
Item is New, never used.
They make an energy save plug. The unit has a tem senser in it that attaches to the outlet hose to the heater core . If the hose is 20 degrees or colder the unit will turn the block heater and then turn it off when the hose get to 40 degrees. The receptacle end has a curved spot on it to go on heater hose.
In that search, also came across this tester, useful for someone who can't/won't/shouldn't be using a multimeter:
Plug Alive Block Heater/Outlet Tester | Canadian Tire
Nice that it is smart enough to distinguish if the heater is drawing power.
Rgds, D.