Not an exact science I know, but I am really confused about what to do for my situation. My house was built 4 years ago and it is well insulated with a two story great room with a wall of windows facing south -- great heat in the winter. The total heated square footage is nearly 6,000 so you would think that I would need a huge outdoor wood boiler. However, the house is currently heated with a 100,000 BTU propane furnace and a 24,000 BTU heat pump. That's it! We live in Virginia by the way. So, should I size based upon square footage or the BTUs of my current system? Thanks for the info.
Sizing an OWB
- Thread starter Chris D.
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What type are you thinking about? In our area(Mich) you do not want to undersize them or your draft will be on all the time and you will be loading it a lot more often.
Gary
Gary
Gooserider
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Chris D. said:
First off, I'd ask if you really want an OWB? I would strongly suggest going with a modern gasifying type boiler with storage, or possibly a Garn, either of which can be put in an outbuilding if you don't want it in the house. You will burn less wood, and make a lot less pollution... This is especially the case in an area like VA that has to be able to handle pretty severe cold, but most of the time has relatively mild temps and low heat loads...
That said, what you should really do is a proper "Manual J" heat load type calculation and figure out exactly what your heat load is. A short-form version of this calculation is at http://www.refined-home.com/knowledge/plumbing/hloadcalc.htm it will at least give you a rough estimate. You should then size to fit the heat load.
The square footage rules for sizing are at best a bad shortcut used by lazy contractors that can't be bothered to do a proper Manual J... Your current system capacity may give you a good approximation, if you do a heat load calc, and come up with an answer that is way different than the current system, that may be a sign that you made an error.
Gooserider
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