Posted By NRT.Rob on 01 Apr 2011 10:33 AM
bad day morgen? seems a little unnecessarily snarky.
Mike, you got anything to relate that info to degree days? that's the real "money" comparison. though what you have there is obvious enough to make a good case for your particular situation at least.
True-dat! BTUs/year can change with the weather that year...
...and the weatherization upgrades to the building- was this the ONLY efficiency upgrade to take place during the relevant time periods?
Many 50-70 year old heating systems were overdesigned by 100-200% for the actual heat load of the building when installed, and now that the place has been tightened up, insulation & better windows installed they end up being 400% oversized or more.
It wouldn't be a surprise to find a 5x oversized antique steam heating plant would be running at only ~50% efficiency even on design day, and that a right-sized low temp system running near it's AFUE would cut fuel use by more than half. My niece's place uses slightly less than half the fuel that it did with the almost-right-sized 85.5% AFUE cast-iron boiler + 140F baseboard system than it did with the 1920s vintage coal fired steam boiler with a 1980s vintage gas retrofit burner, but her basement is no longer 75-80F all winter keeping the mice all warm & cozy.
Radiant and condensing would have been nice, but impossible on her budget. Getting the burner sized correctly is huge, modulating load & condensing is the frosting on the cake when looking at replacing these ancient beasts. Yet 150-200% oversizing is still rampant, even with mod-con installations (out of fear that during a cold snap it might actually get down to -120F or something?).