Gas vs electric cost calculation?
If you are paying for your own electric, when does it pay to use gas instead? Is there a formula? Thanks!
Forum Discussion
To do what?
If you are running some sort of resistance heater, as in the 120V option on a RV fridge, a water heater element, heat strips in your A/C, the conversion is 1 KWH = 3412 BTUs. LPG is 21,500 BTU's per pound, so a pound is equivalent to a little more than 6 KWH, but low efficiency in your appliance might make that 4 or 5 KWH. To convert that to cost, you need to know the cost of LPG per pound, the cost of electricity per KWH. The latter varies considerably with location.
Most places in the country, the cost of electric power is high enough that residential customers will opt for fossil fuels (natural gas, LPG, fuel oil) for heat, if locally available. For heating a residential space, a heat pump changes that. Heat pumps in the right operating conditions can provide five to nine times the BTU per KWH, compared to resistance heating. So if you have a heat pump, use it.
RVer's choice of energy source, particularly for space heating, is usually based on something other than cost.
First, the electricity may be "free" meaning you've paid for it with your site rental, whether you use it or not. That's when we start dragging in 1500 watt space heaters (A/C heat strip is usually the same size). Two of them represent 1/3 to 1/5 the useful output of a typical RV furnace, and if you leave them on 24/7 it might be about the same heat as you get from the furnace in a moderately cold conditions duty cycle. But if it is cold enough for the furnace to be running 100%, then space heaters might not be enough.
Second, a lot of RVers find dealing with LPG to be a hassle. Moving the RV to fill a permanently mounted 9 to 30 gallon tank, or wrestling with 20 to 40 pound portable bottles. I know one who went 15 years without filling his LPG tank, rigged the motorhome to use a 20 pound bottle of LPG and used it for cooking only. If it got cold enough to need the furnace, he didn't go.
Third, when it gets cold enough, only the furnace will do the whole job, which often includes heating utility spaces. It might be a LPG system, it might be oil fired, in which case the costs include paying road taxes on fuel oil bought as diesel fuel.
Fourth, using electricity for these heating tasks means hooking up to the power grid. Off the grid, you heat with fossil fuel, or you use a generator to get power, and that is a less efficient use of the fossil fuel, unless you are using the generated power to run a heat pump.
If you are running some sort of resistance heater, as in the 120V option on a RV fridge, a water heater element, heat strips in your A/C, the conversion is 1 KWH = 3412 BTUs. LPG is 21,500 BTU's per pound, so a pound is equivalent to a little more than 6 KWH, but low efficiency in your appliance might make that 4 or 5 KWH. To convert that to cost, you need to know the cost of LPG per pound, the cost of electricity per KWH. The latter varies considerably with location.
Most places in the country, the cost of electric power is high enough that residential customers will opt for fossil fuels (natural gas, LPG, fuel oil) for heat, if locally available. For heating a residential space, a heat pump changes that. Heat pumps in the right operating conditions can provide five to nine times the BTU per KWH, compared to resistance heating. So if you have a heat pump, use it.
RVer's choice of energy source, particularly for space heating, is usually based on something other than cost.
First, the electricity may be "free" meaning you've paid for it with your site rental, whether you use it or not. That's when we start dragging in 1500 watt space heaters (A/C heat strip is usually the same size). Two of them represent 1/3 to 1/5 the useful output of a typical RV furnace, and if you leave them on 24/7 it might be about the same heat as you get from the furnace in a moderately cold conditions duty cycle. But if it is cold enough for the furnace to be running 100%, then space heaters might not be enough.
Second, a lot of RVers find dealing with LPG to be a hassle. Moving the RV to fill a permanently mounted 9 to 30 gallon tank, or wrestling with 20 to 40 pound portable bottles. I know one who went 15 years without filling his LPG tank, rigged the motorhome to use a 20 pound bottle of LPG and used it for cooking only. If it got cold enough to need the furnace, he didn't go.
Third, when it gets cold enough, only the furnace will do the whole job, which often includes heating utility spaces. It might be a LPG system, it might be oil fired, in which case the costs include paying road taxes on fuel oil bought as diesel fuel.
Fourth, using electricity for these heating tasks means hooking up to the power grid. Off the grid, you heat with fossil fuel, or you use a generator to get power, and that is a less efficient use of the fossil fuel, unless you are using the generated power to run a heat pump.
