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Discussion Starter #1
I have these slanted wall/ceiling segments all around the perimeter of house


Under a thermal camera, they appear to be much less insulated than my walls or ceilings.


Fireplace


Probably fire code to not to have insulation around a fireplace?


I have 3 bathroom vents, they are all about 115f.




Master bathroom has several hot spots for some reason.


outdoors it is 95f right now


my attic is around 125f
 

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Ouch, reminds me of the first few times I went out to play with my infrared camera, a real shocker. What do you have for a camera, I see Flir but no other temp indicators that I can read? You definitely have some work ahead of you and that camera will pay for itself big time.

I'll skim through these so I don't write a book. We can go back as needed.

Slopes are always a challenge to get enough insulation into the cavities along with ventilation, however the bright hot areas are from the framing not a lack of insulation. We will need to figure that out.

No, fire codes don't limit the insulation where you are seeing hot areas, I suspect the builder did.

Attic temp is what we would expect. Vents are hot because they are probably not well insulated up there.

I'll stop there and note, I hate doing IR work during hot summer months. Cold weather provides a much better indicator (at least for me) so fall and winter will be even more revealing.

Bud

Also, what climate region are you in?
 

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Discussion Starter #3
It's a Flir one pro I picked up for some electronic work,
Was playing around with it and noticed all the hot spots in my house lol.

I'm in Dallas, Texas.

Trying to do some very rough math so get an idea what the A/C cost might be...
135ft of perimeter, 2ft high, total surface area=25m^2
15f above indoor ambient at the hottest points,
but i'm putting the average temp at maybe 5f above indoor ambient
that works out to r4-ish
25m^2 R4 should be something like 700W at peak texas temps.

The bathroom vents are going to be harder to guess, because air can flow though them.
 

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Doesn't sound like you will be getting a lot of the cool temps I like, like zero outside and 70° inside.

When viewing those slopes you need to consider if the sun is directly heating those rafters while you are viewing the inside. Note your fireplace image is reversed, hot in the cavity between studs and cool at the stud as the wall cavities have no ventilation, just insulation.

As for calculating the cost of a single area it is difficult. I use the equations from "Residential Energy" and BTUh is U x A x delta T. That's BTU per hour
U = 1/R A = area in ft² and delta T is in F°

Do you know what is up there, 2x? with how much insulation and ventilation space above it. Even once you know, the improvement is difficult, like remove the drywall, increase the depth, add some rigid for a thermal break, and when it is all done calculate how much you would save vs the cost. Payback is usually off the chart.

But those vents if they are accessible could be easier to fix with a worthwhile payback.

Bud
 
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