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Heat loss calculation for rooms with high base temperature
A quick thank you to all who are a part of this website. It has really helped me learn a lot about my home HVAC needs.
TLDR: can I get a more accurate heating loss calculation if I know the outside temperature and the coldest temperature a room reaches when the heating system I intend to replace is left off?
I actually have three rooms I'd like to get an accurate heat loss calculation for, two of which are directly connected to the rest of the home (no closed doors) and each take on quite a bit of heat from the rest of the home. Example: my kitchen, even when it was -9 over night and I had the heat in that room OFF all night, never dipped below 53 degrees. It seems like there should be a way to use this information to know- given the size of the kitchen- nearly exactly how much heat that room needs.
Even more details:
I bought a large (5000 SQ ft) place- originally built in 1890- in Dayton Ohio this past June. I knew my heating bills were going to be "bad" this first winter and I've not been disappointed. Nearly $700 total gas and electric bills in December and January so far. Anticipate ticking just above the $700 mark in February.
As one might imagine, with this size and age house there is a lot of room for improvement. This will be a process, and some steps in this process I have identified are air sealing, bringing insulation up to snuff, and replacement of windows (all windows are still original; none can be opened, and rehabbing is not desirable).
The biggest thing at this point, though, is to get away from the electrical heat coming on when it gets too cold for the heat pump to be efficient. Which is basically 2/3 or so of the entire winter.
I will be adding hot water radiators and/or hot water radiant floor heat to three rooms in my house that currently heat using a heat pump; but it supplements using electrical heat (kitchen, family room, and a rear bedroom) when it gets too cold out. The rest of the house has original hot water radiators and they work great.
The heat pump worked great for cooling this past summer BTW, so I don't intend to replace it entirely.