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Chimney & Fireplaces/replace 1 furnace 1 hot water tank with 4


I have a 4-family house with 1 furnace and 1 100 gal hot water tank. I would like each tenant to have their own furnace and hot water (and pay for them). My question is: will the existing chimney handle the upgrade?

the details:

furnace: economite 3400N02 code 80 max input 400,000 min input 120,000.
hot water: AO Smith 100 gal pcg 100 230. input 75,000

chimney: round approx 10" inside diameter goes from the basement for two stories. A metal extension (which fits on the outside of my chimney - there is a 3 story house attached to mine) goes up one story and has a diameter about 13 inches.

three apartments are about 800 sq feet the fourth is about 700 sq feet.

Hello David, I ran some quick numbers for a 30' tall chimney 10" round and 8 units, and you should be able to get 4-40,000 but hot water heaters and 4-70,000 but boilers, into an 9" round liner (will hold 470,000 but's) so total input of all units 440,000 input btu's, so it should work (this is with out seeing it),  now in most cases to run individuale hot water and heat to each unit requires re piping each unit so you would need to speak to a heating contractor. I would have a local Certified Chimney Sweep, (there you can look up by zip code to find one near you) take a first hand look at what you have, they should be able to help.
Hope this helps
Happy Holidays

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James Ball


I am a chimney sweep with over 22 years of experience, CSIA certified and member of the NCSG, I can answer questions about smoky fire places, wood stoves, and heating units (boiler and furnace chimneys) do you need a relining? A cap? And much more


over 22 years

Chimney Safety Institute of America, National Chimney Sweep Guild

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