air intake on oil burning furnace

Old 04-19-03, 10:16 AM
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air intake on oil burning furnace

i have an old home without heat upstairs. i am remodeling a room on the first floor and using that opportunity to run some duct work through the open walls. i have an oil burning furnace distributing forced hot air.

i had a contractor come and give me a very high estimate to do some work, and he had mentioned that the air intake needed to be larger than it is currently. will increasing the size of the air intake to the furnace help to heat the upstairs more efficiently? it seems to me that the more air the furnace takes in, the more it can distribute, is that the case?

also, one other related question. there are 2 rooms that are right next to each other that i am plannig on running duct work into (a bedroom and bathroom). where is the best place to put a tee to split the duct for the 2 rooms, closer to the main duct in the basement where the new duct connects to the starting collar, or closer to where the registers will be installed in the 2 rooms?


Last edited by havab; 04-19-03 at 10:56 AM.
Old 04-19-03, 05:40 PM
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If you are asking about the return air duct to the furnace, you need almost the same amount as the supply ducts. It is difficult to estimate without being able to see it or have dimensions to work with. If you starve the blower, you will have poor air supply to the registers.

I would not suggest splitting a duct after it leaves the trunk. It would be possible to split an 8" into 2 6" ducts but it is poor practice.

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