I have a question about a heat loss calculation done on our house and boiler sizing. We got a heat loss done on our home and it came to just under 50000. Now we were told by other companies that it would take a few hours and cost about 300$ to have it done. The company we went with, it took them about 15 minutes? Does that sound about right? Not sure about the cost. I'm sure they just used a computer program to estimate? About our home. We have a mid 80's garrison south of Boston. It is about 2500 sq feet. Windows are fairly new and it is very well insulated (we were told after an energy audit). We have 4 zones of heat. 2 on the main floor. 1 upstairs and 1 in the basement. The company suggested a Bosch 100 boiler and indirect water heater. Right now we have an old Burnham boiler 154000 btu and a 40 gallon water tank. We use gas and baseboard heating. Any input would be awesome.