Heating Up

Aluminum windows do a pretty good job of warming up a room… in the summer, it may be what some homeowners want, but I’d say most… don’t.

Attics in the triple digits already, Summer seems to be here already :shock: where’d spring go?



It is here in the northeast Tim. Having a nice string of 60 degree days.

Me <-- Jealous

I had my first hot attic Saturday at 129 degrees. I say we’ve crossed over :smiley:

Yep… a bit warm in both valleys. I’m hoping for at least one more cool down.

Already needing 3 pairs of changing clothes now :frowning:

Tim, do you always take your IR cam. in the attic?

Mostly and if paid to.

There are times that space is too limiting, but I’ve had more than a few air leaks @ ductwork and moisture/roof leaks, along with some overheated NM catch my eye to not try to take it where I can.

I don’t miss that Will…I was framing homes north of FM 1960 in the late 70’s, damn near killed me. Soaked from head to toe at 7:00 AM.

It has been at 100 degrees here the last couple days, I’m not looking forward to the extreme heat again anymore than you guys.

Nice images, Tim…!

Those scans are good examples of radiant heat transfer!

In the first scan, the heat transfer is primarily from radiation not from conduction through aluminum windows. Radiant energy is trapped between the window and the draperies causing convection which is escaping at the top (and subsequently drawing in air from the floor).

This is the same type of thing that happens when Fiberglas Batt insulation on a vertical wall is not properly installed. If you have a gap between the insulation in the sheet rock you will create a convection just like this and cause significant energy loss/gain through the wall, even though insulation is present.

They don’t staple insulation to the wall anymore and they frequently will fall back allowing this to occur.

In the second scan we can dig a little deeper as to what is going on with the camera measurement. The air nor the roof deck is 124°. There are examples of conduction, convection as well as radiation visible in this scan. A little more fine-tuning with another program can pull these occurrences out as being more obvious. There’s a lot going on in this scan!

Remember: if we want to measure something in these conditions we must adjust the camera to isolate the target area and remove the outside affects producing the camera measurement such as incident radiation. For example, the highest temperature in the scan is where the rafter connects to the roof deck. Why is this? Geometry, mass, convective cooling, emissivity, reflectivity or all of the above? A: All of the above.

One of the reasons that it is taught that thermal imaging should not be conducted under solar loads is that there are multiple conditions affecting the camera measurement that are difficult to isolate and remove to obtain a proper corrected temperature.

Not that these dramatic thermal scans cannot be used for building analysis, but careful consideration should be given to what we are actually focusing on within the scan. For example, solar energy eventually makes it to the inside of the house by numerous cycles of radiation conduction and convection as it passes from the exterior to the interior. This scan can be used to identify the ratio of radiant heat transfer to conducted heat transfer. If there is a problem with indoor air temperatures in this area the first thing most contractors will do would be to add more insulation. For the most part there isn’t enough room in the attic for enough insulation. The most effective remediation indicated by this thermal scan is obviously a reflective thermal barrier in association with conductive ventilation systems.

Thanks for sharing your scans Tim.

That was a pretty impressive assessment David. I guess I will need at least a Level II to understand the theory that you have laid out. I am curious about the air gap between the insulation and the drywall…I thought that was always a benefit in total R value.

Chicago was mid eighties today.
That sun is staying up late now.

Excellent observation… I’ll be sure to share some others as well.

Nice work David. I appreciate you sharing your expertise.

If it weren’t for the high humidity it’d be ok. At least we are not up to the triple digits but the attics are still killers.