sizing question for btu on new furnace

[djrocketodd]

Hey Everyone,

I got a couple quotes and different opinions on sizing for new furnaces. I am replacing 2x25 year old 90,000 btu lennox furnaces.

I am looking at 2 95% efficient furnaces with ECM motors.
My house has the upstairs which is 850 sq ft, the main is 950 sq ft

one furnace runs the upstairs the other runs the main floor and 2 vents in the basement. (not need much heat down there)

one quote said a armstrong air 90,000 for main floor and a 70,000 for upper.

the other quote said 2x 60,000 goodman furnaces. and told me a 90,000 is way to much for the size of the house.

Can anyone chime in and let me know what they feel would be good sizing for the 95% efficiency furnaces for the sizes of my house.

Cheers,

djrocketodd

[beenthere]

90,000 sounds grossly over sized for a house of your size.

[Tommy knocker]

180,000 on 1800 sqft a bit much. Resizing both will probably require more then just replacing the units. Should be able to handle that space with much less but it's really not that easy to get there from here.

[turkey]

Do you live in Alaska with paper walls. I've done 1800 sq feet with one 60,000 furnace in northern central Ontario do you self a favor and get a heat loss calc done on your house

[OldSchoolMech]

Where is this house located. ???

Sounds very very over sized to me

[BaldLoonie]

In our cold climate for a house of that size we would have 1 70,000 BTU furnace typical construction. So I can't imagine meeting anywhere near what those dealers are suggesting.

Find a good dealer who will do a heat loss calculation.

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[djrocketodd]

I live in Calgary Alberta, so it does get a little cold and the house was built in 1986. I want to keep the split of main and upstairs separate since there is no zoning in the house. Thanks for the input, i felt 90k was a bit overkill as well.

[2old2rock]

2 - 40,000 btu units sound just about right.

[54regcab]

2 - 40,000 btu units sound just about right.

+1

[martyinlincoln]

Might even want to go to the next level and get a pair of 2 stage 40-45,000 furnaces. There's not much cost difference and quite a bit more comfort. The upstairs unit will probably never go to high fire.

[Tommy knocker]

Might even want to go to the next level and get a pair of 2 stage 40-45,000 furnaces. There's not much cost difference and quite a bit more comfort. The upstairs unit will probably never go to high fire.

Ya. What he said.

[dan sw fl]

2 - 40,000 btu units sound just about right.

Ditto

[tedkidd]

Love Calgary, awesome town.

pair of 2 stage 40-45,000 furnaces.

x3. Nice suggestion.

Look for turn-down to 20-24k. Then the equipment will only be over sized 20% of the time instead of 90%.

Get a load calc and blower door. Please share cfm50 number, and make sure they use that leakage in the calc.