: : Are the baseboard heaters hot water, fed from an oil-fired boiler, or : something else? CY: Think that's it.
: : >My question is when should I use the gas fireplace in order to : >maximize heat and minimize cost? : : Answering that requires more information than you've provided. Here's : how you might go about it: : : - Look up the energy content of the propane, in BTU/gal. CY: I had that figure awhile back. It's 21,500 BTU per pound.
: : - Multiply by the efficiency of the fireplace to determine how many of : those BTUs end up in your house. This number can vary widely - some : fireplaces look pretty but send most of the heat up the chimney, while : others have a heat exchanger to put most of the heat into the room. The : result will be in useful BTU/gal. CY: Figure about 0.80 is a good SWAG.
: : - Divide by the fuel price to get useful BTU per dollar. CY: I'd think you'd want to get the dollars per BTU. After all, we price gasoline by $ per galon. Though, BTU per dollar is also useful.
: : - Do the same calculation with oil. The efficiency of the system : depends on both the efficiency of the boiler and how much of the heat in : the water makes it into your rooms. CY: Fuel oil, I remember is about 140,000 BTU per galon.
: : When you're done, you should know whether it's cheaper to get raw BTUs : from propane or oil. Then you have to take localization into account. : If you're in the room with the fireplace, it's likely cheaper to use the : fireplace to warm just than room than it is to use the boiler to warm : the whole house, because the fireplace *isn't* warming the whole house. : On the other hand, trying to use the fireplace to warm rooms other than : the one it is in is likely pointless. The fireplace just isn't going to : warm the whole house. CY: Excellent advice.
: : Dave