Since some home inspectors come from the trades and may have been a specialist themselves, they will look at certain systems in much more detail and greatly exceed the SOP, and they may be qualified to do so in that area. But this can be confusing for a new guy. The technical dialogue surrounding this level of inspection is probably coming from guys with an HVAC background or who have been doing home inspections a long time and have learned a lot about HVAC.
I’m neither, so here’s my two cents: We’re talking about evaluating the heating and cooling as part of a general home inspection. If I bump the thermostat down, air that is cool to the touch comes out of the supply vents, and the temperature starts dropping in the home, then the cooling system is doing what it’s supposed to. Vice versa for heating. That’s what my client wants to know. If you’re qualified to do more than that, then great. You have a competitive advantage that many clients will value.
My advice to the OP is this: You felt you needed advice as to whether there actually was a problem or not. This shows you exceeded the SOP in an area that was beyond your personal limitations. And that’s okay. It’s good to try to learn more and not just stick with the basics. But in this case, consider taking a step back behind the SOP and keep moving with the inspection.
You shouldn’t. That’s a slippery slope. Imagine giving all of this data to a client and leaving him the impression that adequacy and balance were ok. Then the following summer his house is sweltering. He’d be pretty mad.
Now imagine a client who was given a report that stated the equipment was functional and free of scorching, leaks, etc., etc., at the time of the inspection, but per state standards of practice, thermal performance of the building and the adequacy and balance of the system were not measured, and further stated a recommendation for further analysis by a qualified HVAC contractor to determine adequacy and balance. That guy, had he not reached out to an HVAC contractor, would be kicking himself, and not you.
Hi all. Just seeing the lengthy thread this generated. Thanks, all, for your input. And if it matters / changes anything, I was specifically talking about the heating component (did not check AC due to outdoor temps). And the entire system had been running for about 10 min before I tested anything. The room with the lower temp (and what definitely felt like much lower air flow, with register fully open) was sort of “middle of the house” - i.e. not the furthest from the furnace. I went back and checked it again, as well as 2 of the other registers, just to see if there were any changes, and the temps were consistent. I get and appreciate what some have said in regard to this being a “slippery slope”, and I am most definitely not an HVAC specialist. But I also try to look at this as a homebuyer, and if I were buying a brand-new home, I’d want those kind of data to make sure the builder and subs did their work correctly, while it is still under some sort of warranty, then to wonder 2-3 years down the line why this bedroom is always so cold in winter. I worded it as simply an observed data point (the air from this register was about 10 degrees cooler than all other registers) and took Brian’s advice and added something how this may affect occupant comfort, etc. As for any recommendation, it seems like (unless I’m misreading some posts) some of you are saying that making recommendations that a given ‘subject area expert’ assess the noted issue is being alarmist? Again, I may be misreading intent, but to just note what may be an issue (possibly significant temp diff at a register) and to NOT give a recommendation for what to consider doing about this, would seem to do a disservice to the buyer, yes? In other words, shouldn’t we be at least advising them on which expert to consider consulting for a given problem? Whether they do it or not is on them. But if I note an issue, then make no recommendation, don’t you think the buyer would be much more inclined to ignore it? Or at the least, it seems like the inspector would be more legally ‘at risk’ to NOT make a recommendation if an issue is noted, and less at risk if a rec is made and the buyer chooses not to follow it (or they follow it and it was found to be ‘normal’ or not deficient). But again, thanks for all the input!
If you were buying a brand new home, you should be asking for copies of the Manual J and Manual D calculations for your system. In my area, you cannot construct a home or an addition and get permit approval without them. They exist somewhere. If the property is out in the hinterland somewhere where they play loose with the rules, then you should at least be getting an HVAC contractor out there to confirm adequacy and balance. The home buyer needs to be made aware in the home inspection report that adequacy and balance are not part of home inspection standards of practice.
With that said, if you’re a properly equipped HVAC contractor that does home inspections, you can certainly attest to your findings in the report.
It’s simple if you learn it, Psycrometrics.
Want to fix it, Thermodynamics.
Cold Air has to do with Temperature, not comfort. In my post above I gave a factual example of how you will have the same comfort level at both 64 and 80F.
An oversized unit creates a cave environment which is only comfortable when you enter it from 95F outdoors. Stay in there a while and you feel cold and wet.
When the majority of homeowners think if they turn down the thermostat to 50F, it will get colder, faster, you always will get those calls. Stick to the SOP and don’t even try to answer them.
I had an office building where the boss had the thermostat in her office that controlled the cubical offices outside of it. Everyone was bitching about comfort. Everything was operating as designed but the boss would have nothing to do with it.
My solution: I gave her, her own thermostat.
It was hooked up to a fart fan sitting above the ceiling tiles, going nowhere. Because she could hear the motor, she stopped complaining. There is such a thing as “psychological comfort”. Now try to make an accurate inspection test out of that one.
This is the ASHRAE psycrometric chart for ambient indoor air conditions that outline comfort zones. The range is 68F to 81F. Why would anyone not be comfortable at those temperatures? Maybe because of the 20-80% relative humidity that the thermometer can not measure.
I did make a spreadsheet when I was in school which I used when I started doing Home Inspections where it would calculate the apparent HVAC Btu/Hr output of the equipment compared to it’s rating. There were dozens of calculations that I didn’t want to have to do longhand over and over again in school. Just a few input measurements and it spit out the Btu/hr performance. No, there is no easy way, and the tools to to get the measurements are not cheap to just use for a HI. Never-mind the EPA Certification that is required.
Why would this happen when HI SOP says in several places that this is not your job?
Yup. Even in the stupid states that require Delta-T measurements, you are not qualified to make that determination.
Lets not get stupid here. You can tell if it’s working using the back of your hand (which by the way is more sensitive than a thermal camera and actually senses entalpy). When you pull out that stupid thermometer is when you start being wrong!
Amen brother…One of the topics at my presentation at the Inspector Pro Conference in Ontario, was why it is ridiculously beyond our SoP and capabilities (for 99% of us) to accurately measure Delta T. Pointing your $2000 Flir at the return air plenum and room register is just pretending to do something.
As I posted numerous times in the past, thermal cameras and thermal thermometers are about the worst test devices you can use (without lots of training).
A thermistor thermometer IS the device to measure fluids (air and water).
