Propane or Electric?

[hosspuller]

The method I used to compare propane/electric cost is the energy content.

propane = 91700 BTU per gallon

Electric = 3413 BTU per KWh

so it takes 91700 / 3413 or 26.8 KWh to equal a gallon propane at 100% efficiency. I figure electric to be 100 % while propane is about 90 - 95% since there is heat lost up the flue. (even ventless propane use requires a fresh air source, that's some heat loss)

 

[buickanddeere]

Tankless LP water heater with a water softener. Add a hot water heat exchanger in the furnace plenum for LP backup heat.
Never liked open flame in the kitchen, prefer an electric stove.

 

[tkappeler]

The method I used to compare propane/electric cost is the energy content.

propane = 91700 BTU per gallon

Electric = 3413 BTU per KWh

so it takes 91700 / 3413 or 26.8 KWh to equal a gallon propane at 100% efficiency. I figure electric to be 100 % while propane is about 90 - 95% since there is heat lost up the flue. (even ventless propane use requires a fresh air source, that's some heat loss)

Thanks! This is the kind of comparison I was hoping to find.

 

[JRobyn]

We went with propane for cooktop, a small space heater in the breakfast nook, and fireplace lighter. Solved the unsightly tank issue by using an underground tank (very nice; only a 2ft dia black plastic "lid" for filling). Also have a wood-fired furnace in series with the electric heatpump ducting. We'll only fire the wood furnace when it is very cold outside and we are there for more than just the weekend. The wood furnace has a supplemental domestic hot water coil in the firebox to help out the electric water heater. Many of the wood furnaces we looked at had this as a low-cost option.

 

[Pilot]

Go beyond cost. Consider convenience, reliability, cleanliness & labor.

We have wood, propane & a heat pump. Wood takes a fair amount of work--cut the trees, haul, split, store, haul into the house, clean the house more often due to smoke & ash and it heats the house unevenly, although not so bad if you have a wood stove in the basement. Or are you going to buy the wood? If so, I wouldn't bother with wood except to have a nice fire now and then. Propane prices vary with the price of gasoline so you may see really high prices at times. Price of propane has gone up a lot since we build 20 years ago, when we paid about $.75 per gallon--now it's around $3. And watch out for the supplier--some are real scumbags & I'll never go with Suburban, but that's another story. Heat pump is cheap if temps are in mid 40's or higher. House is more comfortable with heat pump--propane blows hotter air and makes the house feel too hot, then it cools down more before it kicks back on again. HP blows warm air, not as hot as propane, takes longer to heat the house, but it doesn't cool down as much before it kicks on again, so the house temp is more uniform.

If your area has a lot of power outages, get the biggest generator you can afford. We run our furnace fan, well pump and some lights on the generator. Most outages are in the winter, so I am going to rewire and take the freezer off the generator circuit and use that circuit for something else.

 

[kenmac]

House is more comfortable with heat pump--propane blows hotter air and makes the house feel too hot, then it cools down more before it kicks back on again. HP blows warm air, not as hot as propane, takes longer to heat the house, but it doesn't cool down as much before it kicks on again, so the house temp is more uniform.
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If your house gets to cold b-4 the propane faf kicks back on something is wrong ( t.stat or t.stat placement. You shouldn't see anymore than a 1-2 temp difference from (set temp.) B-4 the furnace switches back on.2 deg would be an old mercury style t.stat. Newer ones about 1 deg.

 

[grsthegreat]

Im an electrical contractotr. I live and work in the sticks of North Idaho. Here power outages are a way of life.

My house used to be 100% electric, now i have elect heat pump with propane backup heat source, propane water heaters (2 in series), gas clothes dryer , and propane cooktop.

Heres the reason why:

power outages..........


With the house on a standby generator, i can easily and cheaply power up all these appliances with a smaller generator. All i require is minor power for the ignition circuits and or fan circuits. all the heavy loads are eliminated and replaced with propane.

the size generator required to power the above if all were electric would be ridiculous to fathom.

I heat the home under normal circumstances with wood from my 20 acres of trees; however on those days or weeks where im too lazy or busy to stoke the fires, the propane heater heats it very nicely. its a 95% efficient unit, so the bills really arn't too high. the house if over-insulated, and that's a plus.

 

[charlz]

Both are expensive options.

I primarily heat with wood pellets with a propane furnace as back up. Wood pellets are about 45% the cost of propane on a btu<->btu basis for me. Pellet stove paid for itself in the first 4.5 years I owned it. My kitchen stove/oven is propane, my water heater is electric.

Pellet stove is cleaner than wood but requires electricity same as the propane furnace which is probably the biggest downside if you have many power outages. We don't get very many power outages here and when we do they don't last more than a few hours. Another downside is I have to fill it twice a day. If we are going to be out of town I switch over to the propane furnace. I didn’t know much about geothermal when I installed my pellet stove but if I had to do it all over again I would really give that a hard look.

I didn't build this house but if I ever do build one I will keep an eye to the future. My water heater is centrally located under some stairs. If natural gas does become available in my area I will not be able to change water heater types without relocating the water heater and re-doing some plumbing. I wish they had at least plumbed in the option to put a solar thermal panel on the roof. My house is two stories and it would require some major work to run plumbing up to the attic. With two kids I believe hot water is a major user of electricity so if I had the option I would have added solar thermal system to at least supplement. I still may do this with a panel located out in the yard and running lines under the house in the crawl space but a lot harder to convince the wife versus a roof mount. The propane furnace can easily be converted to natural gas; the parts are hanging on the wall next to it. I think the lines under the house would have to be replaced in order to carry enough volume but easy access in the crawl space. Future availability of natural gas may be something to consider.

I had not been following your build thread and it looks like you are pretty far along. At this stage I would pay great attention to making the house air tight. Conservation is always going to be cheaper in the long run. I don't know what you are doing for insulation but one of my friends had a quick coat of spray foam put over the inside of all the walls before conventional fiberglass was installed. I think that would really make a difference in a house especially if you get any winter winds. If you are going to put in a wood or maybe pellet stove I would be sure to set it up to use outside air. I finally got around to hooking my pellet stove up to outside air year before last and it really made a difference. My pellet consumption has gone down quite a bit and the house is a lot more comfortable, it doesn’t have those cold spots where air was being pulled in around doors, windows etc. We had an unseasonably cold period this winter where we were 10-20 degrees under average temps and I could really tell the difference.

 

[Pilot]

kenmac,

As I said, the propane blows hotter hair--check it at the outlet, it will be about 15 degrees hotter than heat pump air. That is what makes the house feel too warm, the warm air blowing around your face. Also, the thermostat is usually placed in a hallway where no air is blowing so the hallway is slower to heat, but other rooms have outlets blowing warm air around and people feel too warm before the thermostat senses the warmer temp. With a HP, the air blowing around isn't as warm, so you don't feel as hot before the stat says the house is warm enough.

 

[dave1949]

When we switched from a propane water heater to electric, it raised our electric usage by 100-110 Kwh/month. Just the two of us, both retired and no kids here, so we don't use as much hot water as a working couple/family. Maybe your hot water usage would be 2 to 2.5 times ours? Just a WAG.

If your electric rates is 0.18/Kwh, then say, 300 Kwh would cost $54 per month for an electric water heater. At $3.25/gal. propane, that is 17 gal. worth per month.

I'm pretty sure our old water heater used more than that, but it wasn't a very efficient set-up. It was an indirect-fired type and the boiler was 30 feet away feeding the heat exchange coil through under slab PEX. Our year-round average propane use was 26.25 gal/month, and the only other propane appliance is the range cook top. Heating up a can of soup can't take that much propane. :laughing:

If you do use significant propane, most people can get a better price by owning their own large tank and filling it during the off season.