Interpreting HVAC-CALC Results

[wrldruler]

I am converting my garage into a family room. Trying to figure out whether I can tap into my existing central air or if I need to go with a ductless mini-split.

Did a HVAC-CALC tonight.

Existing: 10,000 Gain, 29,000 Loss

Garage: 6,500 Gain, 13,500 Loss

Total: 16,500 Gain, 42,500 Loss

I have a 1.5 ton 10 SEER A/C, and a 40,000 BTU furnace.

So I am close. But is it too close? Any advice?

Thanks,

Chris

[super_tech_1]

1.5 ton is 18000 btu's of cooling so if you did your numbers right then it looks good. Although mini splits are nice too.

[m kilgore]

Depending on the match between the indoor and outdoor unit you may not be getting close to 18000 BTU's. You would need to find out by posting indoor and outdoor model numbers and see if we could tell you. Is your furnace 80%, 90%? I woud say you are really close but it may work.

[beenthere]

Is that total gain, or sensible gain.

[wrldruler]

Is that total gain, or sensible gain.

12.5K Sensible + 4K Latent = 16.5 Total

[beenthere]

If your OD design is 95, and you did your ID design at 70.
The average 1.5 ton won't have a 12,500 BTU sensible capacity.

So on those 95 degree days it would lose temp a little.

[mark beiser]

In addition to the possibly undersized AC, if your furnace is 80% efficient, you only have 32,000 btu of output, at best.

[wrldruler]

Depending on the match between the indoor and outdoor unit you may not be getting close to 18000 BTU's. You would need to find out by posting indoor and outdoor model numbers and see if we could tell you. Is your furnace 80%, 90%? I woud say you are really close but it may work.

Armstrong Concept 10
SCU10A18A-3A
S/N: 8496B13894

Contractor told me the 18 in the model # means 1.5 ton. Can someone verify that.

Armstrong Ultra II 97
EG6E40DC13-6
S/N: A18170KMA
Natural Gas

Furnance clearly says 40K BTU.

Thanks for your help,

Chris

[beenthere]

Its a nominal 1.5 ton A/C.
Weather its true capacity is 18,000 BTU's or not, that I can't tell you.

[RyanHughes]

Your furnace output won't be 40k btu, as Mark said.

[dash]

I am converting my garage into a family room. Trying to figure out whether I can tap into my existing central air or if I need to go with a ductless mini-split.

Did a HVAC-CALC tonight.

Existing: 10,000 Gain, 29,000 Loss

Garage: 6,500 Gain, 13,500 Loss

Total: 16,500 Gain, 42,500 Loss

I have a 1.5 ton 10 SEER A/C, and a 40,000 BTU furnace.

So I am close. But is it too close? Any advice?

Thanks,

Chris

Was the wall between the home and the garage ,treated as an inside wall in both calculations??

If not the load would be reduced.

[wrldruler]

Was the wall between the home and the garage ,treated as an inside wall in both calculations??

If not the load would be reduced.

I ignored the wall between the garage house. It was not in the calc. Thanks

[Richard Kletty]

Put the mini split in the garage.

Yes the 18 in the serial means 1.5 ton. Total capacity sensible and latent. I doubt it has 18k sensible capacity.