In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Question regarding boiler sizing and IDW
I am replacing my old (1960’s era) Peerless Boiler with a WM Ultra 3.
I did a heat loss calculation (using Slanted Fin software) on my modest house (1600 ft2) and came up 57MBH (outside temp 0F).
We have only one zone in the house (but will be adding a second for the hot water)
My own research suggested the smaller WM boiler (80 MBH).
My installer suggested that I go to the next higher size boiler (105 MBH) due to the indirect HW tank.
Not ssure if it matters but it is a 1 bath home with a 5 gpm showerhead and 4 people living here.
I don’t want to second guess my installer, but I was under the impression (based on what I’ve seen discussed here) that an IDW set up as a priority zone doesn’t get included in the heat loss calc. I could be wrong on that as much of what you folks discuss is over my head.
My question: Are there any drawbacks (other than the small additional cost for the larger boiler) to use the larger size (105 MBH) boiler?
Am I correct in assuming that, since it is a modulating boiler, if I oversized it a bit the “modulating” aspect would help me minimize some of the lost efficiencies (due to an oversized boiler).
Any advice/comments would be much appreciated.