How are you advising home owners on room temps

How are you advising home owners on room temps… See the images attached. I find this in homes with Concrete slab floors with Central heat from the ceilings. The lower half of the room indicated temps in the 60F. and the upper half is 70F. plus.

Ceiling fans, Better Ceiling Diffusers, Or ?

Thanks for your views…





IRC (R303.8 ) says, basically that the dwelling unit shall be provided with heating facilities capable of maintaining a minimum room temp of 68 degrees (F) at a point three feet above the floor and two feet from exterior walls in all habitable rooms. The installation of one or more portable space heaters shall not be used to achieve compliance with this section. When these temps cannot be maintained, the room is not considered habitable.

I don’t think that this can be determined with an infrared camera.

Wild ***** Guess (question) here - were there bushes around the exterior where the lower temps were?

No… Open exterior wall at about 11:00 AM.



Nice to see you can find the code… But you miss the point!



Is not the top half of a room…regardless of where the vents are placed…always warmer? Seems like “Mr. Wizard” taught us something in the '50s about how warm air rises…

Knowing that…and knowing that relevant temps are inside the wall space (and not the temp of the walls themselves) what is the point of the IR photos and question. You’re right…I missed it.

I would advise the Client that the floors may cause them
to feel cold (common to naked slabs), even though
the heater is running. If they understand why the feel
uncomfortable, then they are less likely to call you back
to complain.

In houses with high ceilings and lots of naked slab or cold
tile, I will advise my clients of this “possibility” in order to
head off any complaints before they arise.

I also advise them that we cannot verify if every room in
the house will “feel comfortable” to them during all the
seasons of the year (this is beyond the scope of our

Even if this house meets the “code” it may still cause
some people to feel uncomfortable at times… IMHO

This type of problem is a common issue that is also
overlooked during an energy audit. A cold slab is hard
for some people to get used to, especially as they get
older. They may not be aware of it until after they
get moved in.

When you recommend covering the floors with carpet
and padding, they whine. What can you do?

I think they will start installing more embedded heating
systems in slabs in the future… IMHO.

This is significant air stratification and is likely the result of improper duct design, not just because there is a slab.

If you do not remove the unconditioned air from the floor it cannot be treated at the equipment. Hot and cold fluids do not mix well, so blowing warm air into a cold room is not effective.

Air conditioning/heating systems are" suckers" not “blowers” as everyone precives.
The supply and return registers are probably both in the ceiling. (?)

This causes the conditioned air to short cycle back into the return register without affecting the air at the floor. This condition can get so bad that the furnace may shut off on high temperature sensors.

This is also an efficiency loss as the extremely high temperature difference at the ceiling and upper walls cause faster heat transfer to the outdoors.

This design will work fine in the air-conditioning mode because the cold air falls to the floor from the supply registers and the hot air is being removed from the ceiling where it rises to.

It should also be noted that you cannot design an air duct system to function efficiently in both the heating and cooling modes.

Adding a second return air register at the floor level and switching which register is being utilized between heating and cooling will correct the situation. If you have to pick one location over the other, supply at the ceiling and return at the floor is your best option.

Have fun with this one! You’ll have nothing but arguments from the HVAC and general contractor.

Wrong is wrong, no matter how often you do it, it still remains wrong.

Thanks David thats some very good info…




Just a question/observation - not meant as criticism. Had you run the heat significantly in a cold house immediately before taking the images?

I have found, personally that if I go into a home and run the heat for an extended period, particularly if the temperature when I arrived was low, and raise the indoor temperature too much to quickly - that I tend to see this pattern. I always attributed it to the normal heat rising and ceiling supplies and returns. As I do not see it when I only raise the temps by a degree or so or if the natural delta to outside is already very good.

Poor system design is almost a given around here and we have mostly slabs. And as David said, the systems are designed more with cooling in mind.

I kind of had the same thoughts that Kevin has. I noticed two hot spots in the images that look like the registers. Both are very near the walls.

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Sometimes this is true. You backed up what I said…:mrgreen:

Ron -

Is the duct system typical apt style (eonomy) with supply and returns both high up

Yes. this was an cheap low price home. with the returns up in the ceiling of the hallway. about 25 Feet away from the walls in view.

Please see the walls of this home. This was a high end home 5,000 SQ. The room in view is a slab floor with a 12’ ceiling with a bedroom above.
open exterior walls at about 10:00 AM East & north view. the heat was on for some time on this home. I think inspection was about 5 months back. but it had the same condition. low temps to the flooring with heat gathering at the ceiling. The returns were up high along with the registers.

My camera is a FLIR B2 160X120

Thanks for your views…





A couple of $30 ceiling fans would fix the whole thing

Back to your original question, I would not note anything about that in a report.

Kevin Why ? Is it not an issue? and can it be corrected ?

John McKenna

" I would advise the Client that the floors may cause them
to feel cold (common to naked slabs), even though
the heater is running. If they understand why the feel
uncomfortable, then they are less likely to call you back
to complain."




I just came from an inspection like this and yes, I report it every time I see it.

This may seem insignificant to you, but when the client becomes uncomfortable and eventually learns why, they are more than willing to put the blame on you" the inspector" .

This is a difficult situation to overcome but if you have invested in thermal imaging it is extremely easy to determine and document.

I used to argue for days with contractors about this situation which without any qualitative analysis I would point out. Now however, I can show exactly what is occurring in a visual scan. I have been discussing this problem for years, but until now I have not been able to document exactly what is going on.

If nothing more, the client needs to realize that the HVAC equipment is not at fault for their “discomfort”! The design is inadequate. You guys refer further investigation for all kinds of stuff. Try referring a testing, adjusting and balancing technician (TAB).

We don’t need to enforce any building code or standard, we just need to show that discomfort conditions exist. If you don’t want to become involved, just keep away from it.

When I have time, I will set up an example for this situation as a video to demonstrate fluid dynamics and psychometrics of fluids. Hot and cold fluids do not mix.

Yes, ceiling fans can improve the situation but are not a solution.

Good points.