inadequate system design

[Kenton H. Shepard, CMI]

I inspected a home in which the air conditioning system is not adequate to cool the third floor of a home. Inadequate return air and register size.
I checked the registers during the inspection to ensure that they were putting out cold air but didn't wait to see if the whole house cooled down.

The seller did not disclose the indaequacy as required by law and the buyers, who now own the home, are unhappy.

Do I have liability here?

[Blaine Wiley]

Per the NACHI SOP:

II. The inspector is not required to:

A. Determine the uniformity, temperature, flow, balance, distribution, size, capacity, BTU, or supply adequacy of the cooling system.

[Patrick Bolliger]

That would fall under engineering. A process which home inspectors do not perform. Did you perform engineering work with regards to any other component of the building.. I hope not.. Did you calculate room volume /size, equipment, flow patterns and so on.. No, right?

Now if you are an engineer or in capacity to calculate ,analyze a building component and you disclose it prior to the inspection your taking on more responsibility and risk. There I can see the potential for problems.

[rwand1]

A home depending on size, layout, floors, et ceteras, the ambient temperature inside may take several hours to cool down. If its an older house the duct work maybe existing predating current industry standards. Also heat loss calculations to determine adequacy are outside the scope of inspection.

They maybe able to damper down the lower ducts and push more cold air up to the second and third floor, and or change the blower speed, but again that is all beyond your scope of inspection...It was working at time of inspection...so...

[David A. Andersen]

No.
That is engineering diagnostic. Not Home Inspection.

How many HVAC units did the house have?
Was it zoned?

[Jae Williams]

In my agreement:
The INSPECTOR does not perform engineering, architectural, plumbing, or any other job function requiring an occupational license in the jurisdiction where the inspection is taking place. The INSPECTOR holds no valid occupational license, and is therefore not qualified to perform repair nor function beyond this PREMIUM HOME INSPECTION.
In the report:
Typically, in a multi-level structure the temperature on the second floor may be noticeably warmer than on the first floor. Adjustment of the dampers, either in the duct pipes or in the registers, may frequently help to achieve an equal balance in temperature. This process, however, is mostly “trial and error” and may need to take place over an extended period of time.

The client knows beforehand there will be no technical work performed and that such a condition as you described may or may not be adequate.

Third floors, especially in older houses, can be very difficult to condition equally to the lower floors.

[Robert J. OConnor]

Originally Posted by kshepard

I inspected a home in which the air conditioning system is not adequate to cool the third floor of a home ... I checked the registers during the inspection to ensure that they were putting out cold air but didn't wait to see if the whole house cooled down.

Another reason why just taking temp split readings doesn't tell the whole story, and inspectors need to be aware of the limitations.

But as long as you didn't comment on the ability of the system to cool the house (including very dangerous comments like "cooling appears to be adequate") and had a good written agreement that included limitations on that and/or referenced an industry SOP you should be covered.

As an FYI you can also check things like if the return grille size is about 1 s.f. per ton of cooling as a general rule of thumb, although many would consider checking things like that beyond a typical home inspection.