Propane or Electric back up?

grsthegreat · Feb 27, 2011

i too live in north idaho...athol idaho to be exact. we have a wood fireplace for backup heat source. The primary heater is an electric heat pump with a gas back up (when outside temp is below 20F). Since our electric prices are only $0.06/KWH, electric heat pump seemed the best way to go. I also have a propane backup generator to assist if all else fails. were on a community well system, so i dont have to worry about powering up a well. It helps that im an electrical contractor, so i pre-wired my house for the backup generator. Alot of people up here do plan on using a generator, and i wire alot of houses with that in mind. Also keep in mind that a large instant hot water heater in the electric model takes alot of energy to run., ive hooked up some that need three (3) 60 AMP CIRCUITS TO OPERATE THEM.

Heat pump systems are not complicated, and work very efficiently down to say...+25 F, then either electric or gas backup kicks in raising the cost. I have a 4200 SF house, new construction, heavy on insulation. Not counting initial start up load, ive tested my heat pump while running and it only draws about 32 amps.....remember, a 2000 watt baseboard heater can draw 15-20 amps, and heat 1 room. im heating the entire house for this.

Now, usually when its super cold outside, im burning wood in the fireplace so it really doesnt matter. One further bonus of the heat pump system.....You get air conditioning for no additional cost of equipment. The equipment simply reverses flow. I do like A/C on some of those hot days in the summer. Now i dont have to leave windows open, and dont get a house full of dirt moving with the air.

My 50 Amp propane backup generator cant power up the heat pump, but my backup heat for the heat pump is propane. So my backup genset powers up the gas furnace, most of the lights, refer, freezer, microwave, master bath, entertainment system, and for some reason....my xmas lights. Im not sure why i did that..probably to piss off the neighbors when power fails and my xmas lights are on .:laughing:

:thumbsup:

LD1 · Feb 27, 2011

If my water heater ever craps out, I will be looking at the hep-pump type as well.

But mine is an 85 gallon marathon. Lifetime warrenty and one of the mose efficent electric heaters, so I doubt it will be anytime soon.

But to answer the basic question you asked, propane is ~91,000BTU PER gallon. SO assuming 100% efficency, $2.90 will buy you 91,000BTU's.

At your super low rate of .064 per kwh (mine has been .08 for the last 5 years but just went up to .10

), you can buy ~45000 watts of electricity for the same $2.90. And their is 3.41 BTU's in each watt.

SO...2.90 buys you either 91000BTU's with propane OR 153,000 BTU's of electric. AND since electric is easier to install, and you already have electricity obviously, it would be a no brainer.

Propane would require a tank, you would have to keep an eye on it so you dont run out, and plumbing it in is going to be more $$$ than an electric.

But keep in mind that the HP types are about 3x's more efficent than the electric resistance. So that would be like getting ~450,000BTU's for every $2.90. The only drawback I can see to them is that in the winter, they will cool the room their in unless you vent them to the outside. Kinda the same way a refridgerator puts out heat. But other than that, they are still more efficent and as another poster mentioned, they are not any different than a fridge or freezer.

techman · Feb 27, 2011

At your prices, electric is the way to go. Remember that the heat pump will make heat efficiently down to 0 deg or less. Problem is that it does not make enough heat at very low temps, so a supplement (backup) is needed. At anything but the lowest temps, the electric backup is not on continuously, but only cycles at add heat as needed.

paul

_RaT_ · Feb 27, 2011

Interesting your rates are so low. Are they still that low when you exceed so many KWH aka tiered rates? I cannot help but think that rates will go up on everything electricity especially if the demand for it continues to rise. Also, does 6 cents include transmission and distribution costs? Often time the more KWH you use, the higher the distribution and transmission rates. I can see where solar electricity will never be viable from an economical point of view where your at. Where I am, solar does pay for it self WHEN you include the Federal and State rebates.

PS, are you supplied with electric power by a private utility or a public utility?

grsthegreat · Feb 27, 2011

_RaT_ said:
Interesting your rates are so low. Are they still that low when you exceed so many KWH aka tiered rates? I cannot help but think that rates will go up on everything electricity especially if the demand for it continues to rise. Also, does 6 cents include transmission and distribution costs? Often time the more KWH you use, the higher the distribution and transmission rates. I can see where solar electricity will never be viable from an economical point of view where your at. Where I am, solar does pay for it self WHEN you include the Federal and State rebates.

PS, are you supplied with electric power by a private utility or a public utility?

private utility....no tier is used. we run hydroelectric power here.....the cheepest way to go.no mater how much elect we use....6 cents per kwh