What do you think?

[debluvsken]

Under what "conditions" would you recommend a 125K btu gas furnace 90+ with a 3T a/c.???

[firecontrol]

If the load calculations called for this combination I'd look at reducing the heating load by addressing the building or conditions to lower the heat load. In other words, no, I wouldn't put that small of a/c coil on top of that large of a furnace.

[txcchbubba]

Only under the conditions where a load calculation called for that amount of heat and that amount of cooling (for a particular structure).

[debluvsken]

My contractor says I need this for a three story...he measured the area in the basement where the furnace is and has taken care of any issues for me for 20 yrs. but isn't this a LARGE furnace?

[dash]

My contractor says I need this for a three story...he measured the area in the basement where the furnace is and has taken care of any issues for me for 20 yrs. but isn't this a LARGE furnace?



Depends on your loction,type of construction ,etc.,etc,and the LOAD Calculation.

Manual J from www.accca.org

[debluvsken]

south central pa, brick (little insulation) working on it...n side...not much sun

[dash]

south central pa, brick (little insulation) working on it...n side...not much sun



You need all the construction details for the envelope and then you can have a Manual J done or do it yourself ,on this site for a small fee.


Check here; http://hvaccomputer.com/talkref.asp

[jpb2]

As others have mentioned get a load calculation. The north pole may be a match for that system. Plus i would bet the airflow will be an issue with this as well

[gonekuku]

The difference in BTU's sounds outrageous !!! But without load calcs, it's impossible to guess. So, lets theorize....

I picked Gettysburg, PA and it's average Lows for the coldest and average highs for the hottest months.

Jan avg Inside temp (F) 68
Jan Avg Low (F) 19
Difference (F) 49

Jul avg Inside temp (F) 74
Jul Avg High (F) 86
Difference (F) 12

BTU loss ratio 4.083333333
AC BTU 36000
AC BTU x Ratio 147000

Summer Duct loss 30%
Winter duct loss 15%

AC BTU - Duct loss 25200
Heat BTU - Duct Loss 124950

Your guy might be very close. These calculations are for entertainment value only.