We've been staying long-term in an RV park near our old sticks&bricks while I finish out my employment (I retire TODAY!!! ).
While here our electricity is metered. Our first couple of bills were up there, around $150. So we've been working on conserving.
Which leads me to my question. It's about 40 degrees outside. Which is more economical, our propane heater or the heat pumps in the AC units? We've just about run ourselves out of propane again (it's lasting about a month) and it costs around $100 to fill the tank. Plus we need to break camp and drive our MH a few miles to the propane fill up place. So, beginning this morning we are using the heat pumps. Does anyone know which is cheaper or should we just run on the heat pumps for a month and see what that does to our electric bill?
thx...
-- jcw
bjoyce said
03:10 PM Jan 25, 2008
Propane and electricity costs vary all over. Propane can be anywhere from about $1.40 to $4.00 a gallon (4.2lbs per gallon) and those little 1lb cylinders are about $2.25 each at Wal-Mart for a price of close to $10/gallon with tax. Electricity is sold in kilowatt-hours from about 8c to 25c each. Some places it might make sense to use electricity over propane, other places the other way. The BTU ratio of propane to electricity is 1 gallon of propane has about the same amount of heat as 22 kilowatt hours of electricity at 100% efficiency. People find that for an electric space heater compared to an RV furnace this is about right. But a heat pump at 40 degrees should put out about 11,000 btus using 12amps or so, which I saw quoted somewhere. A space heater puts out 5000 btus for about 12 amps so the ratio for a heat pump is probably more like 11 kilowatt hours to one gallon of propane. But if the outside temps go below 38 degrees a heat pump has to do work harder and do periodic de-ice cycles and will be less efficient, but probably will still beat a space heater. Example: Propane is $2.75/gallon at your campground and electricity is 16c/kilowatt-hour. Propane wins for a space heater since it would take $3.52 of electricity to match, but a heat pump would heat the same for $1.76. How much motor fuel does it take for you to get propane? How much hassle? If you have to drive a motorhome ten miles to get propane, what did that cost you in money and hassle? If you have to drive a 12mpg truck round trip with a 40lb bottle it adds to the propane cost. Run it for a month using heat pumps.
jcw said
04:54 PM Jan 25, 2008
bjoyce wrote:
Propane and electricity costs vary all over. Propane can be anywhere from about $1.40 to $4.00 a gallon (4.2lbs per gallon) and those little 1lb cylinders are about $2.25 each at Wal-Mart for a price of close to $10/gallon with tax. Electricity is sold in kilowatt-hours from about 8c to 25c each. Some places it might make sense to use electricity over propane, other places the other way. The BTU ratio of propane to electricity is 1 gallon of propane has about the same amount of heat as 22 kilowatt hours of electricity at 100% efficiency. People find that for an electric space heater compared to an RV furnace this is about right. But a heat pump at 40 degrees should put out about 11,000 btus using 12amps or so, which I saw quoted somewhere. A space heater puts out 5000 btus for about 12 amps so the ratio for a heat pump is probably more like 11 kilowatt hours to one gallon of propane. But if the outside temps go below 38 degrees a heat pump has to do work harder and do periodic de-ice cycles and will be less efficient, but probably will still beat a space heater. Example: Propane is $2.75/gallon at your campground and electricity is 16c/kilowatt-hour. Propane wins for a space heater since it would take $3.52 of electricity to match, but a heat pump would heat the same for $1.76. How much motor fuel does it take for you to get propane? How much hassle? If you have to drive a motorhome ten miles to get propane, what did that cost you in money and hassle? If you have to drive a 12mpg truck round trip with a 40lb bottle it adds to the propane cost. Run it for a month using heat pumps.
That was an EXTREMELY detailed reply. I'm impressed. I realize that many of your figures are ball-park, examles, and guestimates (along with some specific factoids). I really appreciate the effort. Using these examples I can probably now do some back-of-the-napkin calculations.
But I'll also probably take your last suggestion and try the heat pumps for a month.
thx... -- jcw
bjoyce said
05:40 PM Jan 25, 2008
Propane versus electricity costs comes up a lot on forums and I have a good memory. The problem is people want an either/or answer not "it depends". Many do not realize that electricity and propane costs vary a lot by campground and location. If you are going to be long term you can use propane more efficiently with a catalytic or blue flame propane heater. You would need to put in an internal propane connection, with shut off, and buy a $50 Atwood digital carbon monoxide detector. You will be out real money but will save on propane and battery usage when boondocking. You also need to find a place to put the heater while traveling and when not in use. If you are not moving you can add insulation like skirting, bubble-wrap on inside of the windshield (it works!), plugs in the fans (sold at Camping World), etc., to help keep that heat in. Of course now that you are not working, why not head south?
The BTU ratio of propane to electricity is 1 gallon of propane has about the same amount of heat as 22 kilowatt hours of electricity at 100% efficiency. People find that for an electric space heater compared to an RV furnace this is about right.
But a heat pump at 40 degrees should put out about 11,000 btus using 12amps or so, which I saw quoted somewhere. A space heater puts out 5000 btus for about 12 amps so the ratio for a heat pump is probably more like 11 kilowatt hours to one gallon of propane. But if the outside temps go below 38 degrees a heat pump has to do work harder and do periodic de-ice cycles and will be less efficient, but probably will still beat a space heater.
Example: Propane is $2.75/gallon at your campground and electricity is 16c/kilowatt-hour. Propane wins for a space heater since it would take $3.52 of electricity to match, but a heat pump would heat the same for $1.76.
How much motor fuel does it take for you to get propane? How much hassle? If you have to drive a motorhome ten miles to get propane, what did that cost you in money and hassle? If you have to drive a 12mpg truck round trip with a 40lb bottle it adds to the propane cost.
Run it for a month using heat pumps.
That was an EXTREMELY detailed reply. I'm impressed. I realize that many of your figures are ball-park, examles, and guestimates (along with some specific factoids). I really appreciate the effort. Using these examples I can probably now do some back-of-the-napkin calculations.
But I'll also probably take your last suggestion and try the heat pumps for a month.
thx...
-- jcw
If you are going to be long term you can use propane more efficiently with a catalytic or blue flame propane heater. You would need to put in an internal propane connection, with shut off, and buy a $50 Atwood digital carbon monoxide detector. You will be out real money but will save on propane and battery usage when boondocking. You also need to find a place to put the heater while traveling and when not in use.
If you are not moving you can add insulation like skirting, bubble-wrap on inside of the windshield (it works!), plugs in the fans (sold at Camping World), etc., to help keep that heat in.
Of course now that you are not working, why not head south?