How many BTU do I need

[Vermontster]

I am not a stove builder, salesman or affiliated with the stove business other than as a consumer. So, I am no expert, but I grew up in Northern Vermont in a house about 2600+ square feet. We had a combination oil/wood furnace in the basement. It rocked, I mean kicked a$$. We had to open windows often to cool down, My father fitted it with a hot water heater and we came home one day to find the hot water had melted the washers in the faucets. Crazy. If I could put one in my house, this what I would have. http://www.yukon-eagle.com/FURNACES/EAGLEIHUSKY/tabid/55/Default.aspx

 

[Nofossil]

At this point, I don't know if you feel like your question has been answered or not. I do think that you're right to consider the thermal mass that you will want to warm up quickly. When I built our house, I neglected to take that into account when sizing the oil hot-water baseboards. I painstakingly modeled every heat loss in the house and determined that we needed 52' of baseboard for our 3500 sq ft house, which works out to about 34000 btu/hr. That turns out to be almost exactly right (I can maintain 72 degrees inside at -30 outside) but it takes nearly forever to change the temperature of the house even one degree.

When I added the wood boiler, I had more problems as it doesn't always provide hot water at 180 degrees. At lower temps, the baseboards don't put out as much heat.

As with many things in life, a little overkill is a good thing.