Hi all!
As summer has gone, and the furnace needs to run again, I find myself aware of how often the furnace is kicking on and it's only mildly cold compared to what will be coming to us here in NH. I know I have drafty windows that I have yet to seal, and need to check the make-shift seal around my poorly made attic hatch. And thoughts of how much heat gets wasted up the ceiling vent in the bathroom even though we keep it turned off most all the time... and then wonder how well the walls were actually insulated on the pre-fab house, especially given the quality of the window installation...
This left me wondering, and then searching the internet to no avail,... how long SHOULD my house hold heat? Searching that out leads right into some very complicated mathematical calculations regarding BTU's ,sizes, efficiencies, blah blah blah, which is all great stuff for calculating but I am interested in something far simpler. Specifically, rate at which a home should drop in temperature when the heat is off. The purpose of which would be to determine if there is a problem with insulation or drafts, based on ACTUAL heat loss instead of calculating, extrapolating,... and then just wondering and waiting for the heat bills to add up!
I'm picturing a chart (or calculator) that assumes a house that has been kept at say 68 degrees for a long enough time so that heat loss isn't just from the air at the thermometer into other interior objects. From there, it would be nice to know degree drop per unit time with heat off, for determining the homes ability to hold the heat. With such information, one could easily determine if they need to make improvements or not! The variable would be outside temperature. Additional variable could include wind-chill, otherwise you'd have to test on a calm day! Sunlight would be very significant, so this would have to be a night testing only. But the point here would be to eliminate all the house size and BTU's, which really just muddies the situation when just trying to determine if draft and insulation is actually sufficient. I.E. all the calculations in the world don't really determine if the insulation in that wall is really sufficient, or if those windows were really installed correctly (mine are energy efficient but some were Z'd when installed so I have to seal around them every year). The closest I find to what I'm looking for is when someone has been timing their furnace cycles. But that leads to furnace efficiency complications, on to BTU's, and well... just seems it would be so much easier to just be able to watch the inside temperature with a timer, and log the drop over time along with the outside conditions, and determine the buildings ability to hold the heat.
I would think this information exists somewhere, but I have yet to find it. If you made it this far, thanks for reading! Meanwhile, I'll just go do what I can in the "draft" department and hope propane prices don't break me this year!