replacing Furnace with added space

Old 09-24-08, 10:47 AM
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replacing Furnace with added space

I am wrapping up a reasonably large addition to my older home.

Origional home was a cabin, approx. 700 sf with an old lowboy furnace. First floor I added approxamately 600 sf , cut through old foundation wall and put new registers on the old system.

The new second story is on a new independant system.
I want to remove the old system and the 60 year old duct.

I need to determine the sizing of the replacement furnace and the trunk line serving the area of replaced duct.

The old portion of the house is approximately 20 w x 35 L
there will be 5 registers max. on the 35' run.

any ideas or good ways to calculate would be helpfull.

gross combined area will be floor space of 1300.

Old 09-24-08, 06:25 PM
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Just like all the other post you need to do a heat load manuel J and a duct size manuel D to get this right.

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