Correct sizing

[fat bob]

Originally posted by martik

The energy test report says it was originally 10.85 ACH @50Pa which was equal to approx a 468 sq inch hole.
After the upgrades it went down to 4.5 [/B]

Never mind. Sounds like you had a blower door test. Tight houses can get well under 1 ACH, but that's without a blower forcing air out.

[fl1]

If 30,000 btus is correct,and you get the closet size to it,the cfms reqired ,for each room ,will not exceed the cfms of that unit,period.

More cfms will only be required if you need more btus.

Your ducts are larger than needed,so with VS fan no problem.Standard fan ,you may need a damper in the main trunk to raise the static,to keep the cfm down,so you get a proper temperature rise.

Main thing is to be sure the load calculation is correct,sounds like it could be.

Good idea to calculate the cooling and get a furnace that can handle the tonnage ,if someone ever wants to add cooling.