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Back of the napkin basement heatloss

johns3km | Posted in General Questions on


I’m looking to get a rough ballpark for operating costs to renovate my basement. I thought I could just get away with a couple electric baseboards but my numbers must be wrong as it seems pretty expensive given the size of the space. 

1940s granite block foundation, Boston
7′ ceilings
110′ of walls, 50% above grade, R-15 closed cell
550sf of uninsulated slab
84sf of Harvey windows and 1 exterior door

Roughly 10,000 BTUs @ 9F

I have this costing $3k a year using electric baseboard set at 72F. Is that in the ballpark? I heat my 2000sf house with an old steam boiler for ~$2,000/year. 


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