Guidance on HVAC inspections

Hi Folks,

I’m looking for some input. About a month ago I performed an inspection on a modular home. Did my normal thing when it comes to the AC. As part of the inspection I was taught to check the temperature differential (temperature going in v. temperature coming out). It checked out fine, I think the differential was around 18 degrees. The condenser was installed in 01. Yesterday I received a call from the client stating that she as been having problems with the unit. Her home warranty took care of the repairs but the service tech said the unit is too small for the home.

Do you folks look at the tonnage of the unit and compare it to the sf of the home? For a few reasons, I was told that is better left to an HVAC tech.

Basically, I want to know if I’m not providing as thorough of an inspection to my clients as could be but, also, leaving myself open to liability.



Check out your Standards of Practice (Which one do you use?):

3.5. Cooling

I. The inspector shall inspect:
the cooling system using normal operating controls.

II. The inspector shall describe:
the location of the thermostat for the cooling system; and
the cooling method.

III. The inspector shall report as in need of correction:
any cooling system that did not operate; and
if the cooling system was deemed inaccessible.

IV. The inspector is not required to:
determine the uniformity, temperature, flow, balance, distribution, size, capacity, BTU, or supply adequacy of the cooling system.

inspect portable window units, through-wall units, or electronic air filters.
operate equipment or systems if the exterior temperature is below 65° Fahrenheit, or when other circumstances are not conducive to safe operation or may damage the equipment.
inspect or determine thermostat calibration, cooling anticipation, or automatic setbacks or clocks.
examine electrical current, coolant fluids or gases, or coolant leakage.

Sure he did the dirt bag was trying to sell a new system because he did not know how to repair the one that she was using. Was the A-coil stopped up with lint or do you know

Sure, trust a HVAC tech who’s motivation is to squeeze more money out of you.

I love how we assume the HVAC guy is a snake.

It was working the day of the inspection. Sometimes mechanical things will break. Welcome to home ownership.

Did you miss the bus tire tracks on the OP’s back;-) you just assumed it was working properly the day of inspection

The OP stated the homeowner was having problems with the unit prior to calling the HVAC tech. Those problems would be key information to post here in order to get a better answer.

“Too small” sounds a little bit suspect.


Commenting on the appropriate size of the A/C could pose a problem for you. In many states only a licensed HVAC contractor or engineer can size a unit. Without a thorough energy evaluation and the use of an approved load calculation program you could get an incorrect and unsupporatble answer. Sizing cannot be based totally on square footage.

Was the 18 degrees the difference before and after the coil or at the diffuser and return grill?

Thanks for the info so far.

Totally agree that making a comment on the size of the unit versus the sf of the home is beyond the SOP and a setup for disaster. Glad to see I’m on par with the industry standard.

Because of the configuration of the system I was not able to see the evaporator coil. No idea if it was clean or not. Likely it was dirty. The filter did not seal properly and I informed the buyer that dust was bypassing the filter and this can cause problems.

The 18 degrees was measured between the return and a near by register with a digital thermometer.

To be honest I’m not sure what “problems” the home warranty fixed. The client was a little agitated, which is understandable, and didn’t want to start at the beginning. She kept coming back to the fact that the tech said the unit was too small for the home and she wanted to know why I didn’t catch that.

My assumption here is she’s expecting me to pay for an upgrade. But as has been discussed sizing the system to the home is more involved that simply knowing the tonnage and sf of the home, thus, beyond the scope of the inspection. Sounds like my inspection process is appropriate… I think :wink:

Don’t Think and Don’t Assume, you did the right thing by asking a question now you have answers now go look and confirm what everyone just said and say I know before you talk to the client.

When the return air filters are bypassing or are not present at all you don’t have to see the evaporator coil just remove the front cover on the blower section of the furnace and if the blower motor and the blower wheel is matted with lint you can rest assured the A-coil is in the same condition and that is what you should report

I think; not.

  1. The HVAC guy likely used the same WAG (wild *** guess) load calculation as you mentioned. So you both would be entitled to your “Opinion”. You have a 33% chance of being right.

  2. When you do WAG testing on things outside Home Inspection Standards (“standards” not everyone else’s practices) you put your name on the equipment you assessed and your client has every right to expect you to correct the situation.

Which Industry? Niether from what I can see.

You can not size equipment by s.f. any more than you can determine the proper operation by Delta-T.

Now this is something you as a Home Inspector SHOULD be inspecting. If it’s dirty, the Delta T measurements are “CRAP Information”. So how about checking that first?

This would be one of those reasons.

Don’t know about the sizing of the unit or not but a simple thing to think about is the air filter. A lot of people go with a high efficiency air filter which impedes the air flow to the HVAC system, which in winter with the furnace may not be a big deal but in the summer with the A/C it can be. The A/C needs more air flow to function properly than the furnace does. So Betty homeowner throws that cheap low efficiency filter away and replaces it with a high efficiency one thinking her allergies will be better this year. Not knowing she is actually causing her A/C system to be starved for air, in turn causing it not to properly cool her house down. Could be a simple fix and the HVAC furnace does little to nothing for IAQ it is mainly to keep the dirt and lint down to a minimum in the coil and blower. Also it could be the balance of the system caused by how the duct system is run. It really could be a lot of things none of which is probably part of the home inspection. Balance size layout so on and so forth. The only thing is the filter and if it wasn’t the right size when you where there it has probably been replaced by now.

Sometimes it is the simplest things that make the biggest impact.

May or may not help but it is at-least worth what you paid for it.

Hi All,

This has been some great info! And like most posts on these forums, more information than I needed. Really, I just wanted to make sure I was doing my inspection properly and that my understanding of the limitations is correct. Sounds like it is.

Based on the responses it sounds like I did what I needed to do during the inspection. It is beyond the scope of the inspection to make judgments about the size, layout, balancing and so on, of the system. I had concerns with the equipment (the filter and the dirt bypassing it), I made that clear to the client during the walk thru and in the report. It is unfortunate that she is having problems with the unit but somethings are out of our control.

Thanks again for the advice. It’s very helpful to have this forum and you all to bounce questions off of.

A cracked heat exchanger is not a big deal?

Just gave him another thing to think about. I didn’t say it was the answer to his problem and said nothing about a heat exchanger.

Impeding the airflow can overheat and crack the heat exchanger. You unknowingly mentioned it by mentioning the filter. It’s the end result of the filter issue which you said was not a big deal.

Thanks for the information. I was told it is not AS big of deal as in the winter with the performance of the furnace, but yes impeding the air flow should never be done I agree.