Easy Way to Begin to Determine Adequacy of Insulation in a Attic Space

Just wanted to post a quick tip in case I could be useful for someone new to inspecting or for someone weak in this particular category.

Even though according to the SOP you don’t have to say much in relation to the attic insulation other than missing insulation or obvious shortage, the more you know and can comment on specific systems/components of a home makes you more valuable as an inspector and gives you more authority with clients/realtors. Especially more valuable in terms of annual maintenance inspections.

You can tell the inadequacy of insulation in a variety of ways. You can also show in your report the inadequacy in various ways (thermal imaging, rusted nails, etc.), but one of the easiest and most cost-effective ways to not only get an idea yourself but more importantly, show your client this evidence, is with an infrared thermometer.

Many inspectors use this cost-effective tool to make sure that the HVAC system is functioning properly by measuring the temperature coming out of the vents in the home when running the system.

However, you can also use this tool to take measurements of the temperature of the floors and ceilings in the living space and then in the attic itself to see how the temperature and air is moving through the home.

For example, it is currently winter. That means that homeowners will have their heat on because it is cold outside. Heat rises, so the ceiling should be a few degrees warmer on the ceiling of the living space. Compare that difference to the difference between the ceiling of the living space and the floor of the attic to get an idea of how much heat is being allowed though the insulation.

This, combined with the other things you will pick up along your inspection, can be very effective to not only determine for yourself that the insulation is inadequate but (after taking pictures of the reading on your thermometer) can also be physical evidence to provide a client.

So for all you who may not want to invest in thermal imaging or have the time to learn quite yet. This is a good and cost-effective way to start familiarizing yourself with insulation and heat/energy loss in a home.

Happy Inspecting!

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Merrick,
I do not agree with the information you posted.
Delta T from the interior ceiling to the attic floor is not enough information to determine if insulation is adequate. I’m curious what difference in temperature you would consider to be good.

For example if your ceiling temperature is 70°F and your attic floor temperature is 40°F. How do you determine if this is good or bad without knowing how many air changes per hour your attic has at that moment. Or the tightness of the housing envelope. Or the temperature outside. Or if it is a sunny or cloudy or rainy day. And what roofing material is used. There are so many things.
You can not measure the rate of energy loss simply by temperature delta of those two surfaces.

Example. I had a house one summer where the attic floor was over 150°F. Ceiling temperature was 80°F or more in areas.
that’s a 70° difference between the interior ceiling surface and the attic floor. That’s a huge delta T, so the insulation must be doing a lot of work, right? So Is this good insulation or poor insulation? There is no way to answer the question with only this information. In fact I would say this information is next to useless in answering the question “Do I have good insulation?”.

Insulation slows the rate of energy transfer. Not temperature transfer (which isn’t really a thing).

My quick tip- If you want to estimate the R-value of the insulation measure the thickness (I take an average of several locations) or in the case of Batt insulation it may be printed on the vapor retarder layer. Use a chart to convert your insulation thickness for they type of insulation you have to an estimated R-value. Compare that R-value to the Climate zone recommendations set by the DOE.

Like you do, I use a thermal imaging camera to look for anomalies such as gaps in insulation, missing insulation, displaced insulation batt, and other things. The thermal imager is a useful tool.

I have other tips, but they are not so quick.
.
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Here are some thermal pictures from that attic example I mentioned.
The surface of the blown fiberglass insulation was over 150°F
The interior rooms had ceiling temperatures much higher than the floor temperatures but way cooler than the attic.
Is this adequate insulation?

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"Insulation slows the rate of energy transfer. Not temperature transfer (which isn’t really a thing)." -the energy transfer that we are referring to in this instance is heat transfer. hence, me using the term temperature repeatedly. Technically still correct. Wasn’t going for college course material here.

"In fact I would say this information is next to useless in answering the question “Do I have good insulation?" - as a professional in the insulation industry I would strongly disagree with you. It is typically an extremely good way to get this information and at various companies I have worked for was commonly the very first step in our inspection process before measuring the insulation… unless you are in extreme circumstances. (like 150 degree summer days)

"If you want to estimate the R-value of the insulation measure the thickness (I take an average of several locations) or in the case of Batt insulation it may be printed on the vapor retarder layer." - since this will only provide you with an estimation, gauging the temperature loss in conjunction with the recommended value will help in determining the adequacy of your insulation.

While obviously you are correct, that this is not the end all be all to determining complete energy loss, this is meant to be just another tool in the arsenal (One that even members of the insulation specialty use). Of which you can never have to many.
Next to useless is simply incorrect.

[quote=“mtovey, post:3, topic:189189, full:true”]

As a mechanical engineer and a professional in the insulation industry, I would strongly disagree with you, too. I own InsulationBoss

And I’m sorry, but I HAVE taken the college courses.

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You own an insulation company and have a college degree and don’t know that heat transfer is a type of energy transfer?

We will just have to agree to disagree. Only trying to help. With information that can easily be looked up and validated. If its not for you then don’t follow it.

When did I say that?

I disagree with your “easy way to determine if insulation is adequate” as described in your original post.

" if your ceiling temperature is 70°F and your attic floor temperature is 40°F, how do you determine if this is good or bad without knowing how many air changes per hour your attic has at that moment? Or the tightness of the housing envelope. Or the temperature outside. Or if it is a sunny or cloudy or rainy day. And what roofing material is used. There are so many things.
You can not measure the rate of energy loss simply by temperature delta of those two surfaces."

I agree that thermal imaging can be used by a home inspector to help find a variety of insulation defects.

Temperature and heat transfer are not the same thing.

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As I have said, I was speaking not as a college professor. This was meant to help very beginners. The terminology was mean to be simple to understand. And if you ACTUALLY read the entire thing. I also said multiple time that it was supposed to be used IN CONJUNCTION with other methods. How are you not understanding this?

I have however, learned my lesson on posting in the forum. I am an inspector. Not a writer. So you’ll have to forgive me for being loose with wording. This post is not meant for someone like you who knows the terminology. Its for the greenest of green. Just enough to understand what I’m saying. If you start talking about Delta-T and the envelope of the structure and ALL of the different factors of energy loss in a home then someone who is just starting is going to have NO IDEA what you are talking about. Plus InterNACHI has a ton of courses to take for all the exact science of everything that needs to be done if thats the info you are after.

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And furthermore, heat transfer is the exchange of heat between physical systems. So by me saying that I am taking temperature of each side of a physical system (floor of attic, top of ceiling). I am then, by definition, measuring the heat transfer in that system. Once again, I don’t understand how this is even debatable.

And then what?

I need more information to come to any real conclusion that would be a benefit for my client’s.

What temperature differential would be acceptable?

How would you use the difference in temperature to determine the insulation R-value at the attic floor?

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(keep in mind that thermal imaging is superior and this would be for those who either don’t want to or cant afford to implement thermal)

With this method, an ideal scenario would be that you have evidence that makes you want check in the first place such as rusted nails in the trusses, fungal growth on the wood, condensation, etc.

With the temperature you really are only looking for pretty major changes. Something that lets you know for sure that the hot/cold air from inside is moving to freely through that insulation. That is it.

For me personally, after testing it out in my area (North Georgia) on homes with an absence of insulation and homes that had the recommended depth (In our case the code says R38). I typically start to raise an eyebrow around a 10-15 degree difference. You can confirm suspicions however with some math and some conversion charts.

Always measure the depth if possible. You are not doing this to determine R-Value. The depth will give you the most accurate range. I use this in conjunction with the depth to:

  1. Make sure that while scanning there are no dips/hikes in temp (much like a thermal camera)

  2. See a major temperature changes. (If its 20 degrees outside, It should raise an eyebrow if the attic is 40) you are heating the attic.

What information? How to step right into legal peril?

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Good morning, Merrick.
Hope this post finds you well.

I think the hypotheses you are trying to put forth is, ‘determining the adequacy’ of insulation in an attic space.
Confront your attorney with your SoP and the conjecture. 'for someone new to inspecting or weak in SoP. Tell the members what he/she determines based upon your advice.

Best regards.
Robert Young

Wha? Conduction, convection, and radiation are types of heat transfer, not energy.

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image

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The floor of the attic the top of the insulation. Is there a ratio that determines if it is adequate or not ? If the hatch isn’t insulated that will make a difference in temp. What does proper or improper ventilation do to the temperature? If it’s 20 Degrees outside and the attic is 40 degrees and the ceiling is 78 degrees how much more insulation should we suggest they add?

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Now that’s getting ready for a show.
Didn’t know they sold popcorn in that size?

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