3.5 ton for 2100sf house

M Kelekci · 09-23-2007, 12:55 PM

House got high ceilings, 2100sf. HVAC unit 3.5 ton. I don't think it is big enough to cool the heat load in the house. How would you all word it out on the report?

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**Bruce King** · 09-23-2007, 01:07 PM

Sounds like this is beyond the scope of an inspection but if you want to try to figure it "partially"......

Need to know SEER rating of unit.
1 or 2 story house?
1 or 2 thermostats zoning system present?
Siding material, foundation material, window ratings, number of windows and sizes, attic insulation type and thickness, wall thickness..

See where this is headed?

M Kelekci · 09-23-2007, 01:55 PM

What does SEER have to do with the heat load and tonnage calculations?

**Rick Hurst** · 09-23-2007, 01:56 PM

Matt,

Being in the Houston area, it is probably considered undersized.

In the Dallas area, most HVAC contractors figure about a 1 ton per 1K of square footage.

With the humidity and heat in Houston, I would expect the same.

Most homes I see of that square footage here would have at least a 4-ton and most would have a 5 ton.

rick

M Kelekci · 09-23-2007, 01:59 PM

Originally Posted by Rick Hurst

Matt,

Being in the Houston area, it is probably considered undersized.

In the Dallas area, most HVAC contractors figure about a 1/2 ton per 1K of square footage.

With the humidity and heat in Houston, I would expect the same.

Most homes I see of that square footage here would have at least a 4-ton and most would have a 5 ton.

rick

Did you mean 1 ton per 500 sf?

M Kelekci · 09-23-2007, 02:01 PM

Originally Posted by Fritz Kelly

I make no determination as to whether the unit is sized adequately for the square footage of the home. Consider having the unit evaluated for proper sizing by a licensed HVAC contractor.

If you are calling for a HVAC contractor evaluation, aren't you kind of making a determination that unit is not sufficient?

**Rick Hurst** · 09-23-2007, 02:09 PM

Matt,

Yes I did, and I edited my comment.

**BARRY ADAIR** · 09-23-2007, 02:20 PM

Originally Posted by M Kelekci

If you are calling for a HVAC contractor evaluation, aren't you kind of making a determination that unit is not sufficient?

What checks/tests did you do during your inspection?
You obviously found some other issues, I'd hope.
While the HVAC guy is out there have him size the system and let him make the call.

**Jack Feldmann** · 09-23-2007, 02:49 PM

I guess it really depends on your area. In Knoxville, that would probably be fine.
JF

william siegel · 09-23-2007, 03:16 PM

Air conditioning sizes are done by calculations. I believe it is a Manual J calculation. Rule of thumb is 500 to 600 square feet per ton, but that is only a rule of thumb and may not always be correct. I have, on occassion (once or twice), informed my client that I was not sure if the unit was sized right, and told them that it is done by equasion, and leave them with the option to have a licensed AC company verify the proper size.

Seth Hughes · 09-23-2007, 03:44 PM

A home inspection does not involve the calculations of heat gain necessary to decide if the cooling capacity on a building is adequate, but the inspector is expected to examine and report on the rated system capacity (such as "36,000 BTUH") and on the presence or absence of cooling sources in the habitable rooms of the building.
A simple rule of thumb for relatively cool climates such as the Northeastern United States: one ton per 400 sq.ft. (Commercial) or one ton per 500 to 1000 sq.ft. (Residential) or one ton per 400 to 800 sq.ft. (Space Pak Systems). . Or a 3000 sq.ft. house may require a 5-ton unit. Or count the supply outlets: 10 outlets @ 100 cfm (estimated) = 1,000 cfm = 2.5 tons needed.