DIY air sealing equipment
FrankFulton
| Posted in General Questions on
Other than a blower door, which is impractical for this application, what specifc products do you recommend for a homeowner interested in air sealing? What is the best homeowner-grade thermal imager (if there is one), smoke pencil, etc?
Our moderate retrofit reduced a very leaky, large house from 7330cfm to approx 5000cfm, and I want to keep going.
Thank you.
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Replies
You could build your own blower door - http://www.nlcpr.com/Pressuretesting.php
Or you could just seal all the typical penetrations and hope for the best. A home-owner grade thermal imager won't have a high enough resolution to help you find really small air leaks.
I just turn on the range hood, bathroom fan, and clothes dryer (on air dry mode). This produces a pretty noticeable breeze at every leak point.
I have a Seek Thermal and it is kind of frustratingly blurry, given its low resolution. But it does help. It can highlight the coldest and hottest points on the screen, and this really helps highlight where outdoor air is leaking in. Then you can verify with smoke pencil, incense, or just a wet finger.
I have not used one but FLIR has several kits to make your smart phone into an IR camera. Or you can rent them from some Home depot’s $53 for 4 hours or $75 a day.
https://www.homedepot.com/tool-truck-rental/Thermal-Camera/FLIR-i7/
Nick’s plan with the fans does work. If you have an attic fan, that will move a lot of air.
For smoke I like incense stick from Walmart.
https://www.walmart.com/ip/Gonesh-Extra-Rich-Lavender-Incense-Sticks-20-ct/24864649
Walt
Emerson,
If you don't have a range hood fan vented to the exterior, and your bath fans are wimpy, you can depressurize your house with one or two box fans mounted in an open window. Seal around the box fans with cardboard and duct tape.
Thoughts on the Flir E8? You can actually buy an E4 and hack it to turn it into an E8. Best bang for the buck certainly (up to you if you are comfortable doing so). Still around a $1k investment.
The FLIR One Pro can be found on Ebay for less than $400 and you can probably resell it once done for a net cost of a rental one or less.
To close the loop:
1. I rented a nice FLIR camera from HD ($75).
2. I also purchased a snake LED camera for my iphone ($40).
I am much better able to assess my house.
Thanks for the input.
I disagree completely that consumer grade IR cameras are not useful for air sealing. I have a FLIR One for my phone and between the 160x120 IR image and MSX (edges superimposed from visible light camera) there is MORE than enough information available to be very useful in finding air leaks.
An air gap in a building envelope might itself only be tiny, but the air passing through it affects all of the adjacent material. When looking for air leaks you're looking at relatively large areas that have been cooled by incoming air. From there it's pretty easy to determine where the actual leak is.
Professional level cameras will surely be better, but are absolutely not necessary. Consider the OP's situation. He has 5000 CFM worth of infiltration! With that kind of air movement you'd be able to see leak sources with a FLIR one very easily.
If your business is professional air sealing and you spend your days chasing leaks in very tight homes when the outdoor air is not too far off the indoor conditions, yes, a professional IR camera is for you. If it's cold outside, warm inside, and you just want to see where your normal house is leaking, buy a FLIR One and have some fun!
Here's an example from when I air sealed the rim joist area below my kitchen. Notice in the before picture the large cold spot along the wall to the right, and how it's gone in the after picture. This was a large gap in the rim joist the builders made no effort to block that was handily eliminated with some spray foam. The whole area benefited.
I should mention that I made my own blower door with a box fan sealed into the man-door into the garage with plastic drop sheet. It only took about 20 minutes to set up.
I got nowhere near 50 Pascals of depressurization though; box fans do not do well at creating static pressure. I think I estimated about 10-15 Pa based on the low resolution gauge I was using. This was enough to create easily detectable drafts using my FLIR and a stick of incense (as suggested above).
Make sure you turn off all combustion appliances ahead of doing this! Neither my gas furnace or water heater are sealed combustion units, both use room air as a source.
"A home-owner grade thermal imager won't have a high enough resolution to help you find really small air leaks."
The "really small" is the key. Once you tackle the big, obvious leaks, I haven't found the consumer grade IR cameras to be much use for catching those last air leaks, the ones that an IR camera would be particularly useful for finding. If you aren't trying to find the really small air leaks, just follow all the usual advice for air sealing and you'll get most of them without any IR. And if you want to use a camera to find the big ones, by all means go for it! It's fun to visualize!
Yupster, I need to add one more thing. I would imagine the pro grade cameras offer some functional options which make them easier to use, like being able to specify and lock the displayed temperature range. The phone app is always auto-ranging, which can make finding small temperature gradients more difficult; you need to get closer, not because the resolution is lacking, but because you need to eliminate any objects with varying temperatures from the image. The app allows you to vary the temperature range in post processing, but that's not much help when you're actively looking for things.
I would think the professional cameras would have IR sensors with greater dynamic range as well, allowing the display of greater gradients within an image and giving more flexibility in post processing the images. Ii IR sensors are anything like digital camera sensors, there can be quite a difference in dynamic range from one sensor to the next.
I still must say, I'm BLOWN AWAY by this FLIR One and the fact that this is real pocketable technology that anyone can purchase for a few hundred dollars. If thermal home improvement is something you'll be getting into it's invaluable, and for the cost of a few days rental of a more expensive IR camera you could own this one, even if it's only 80% as good at finding leaks in a building.
Here's a FLIR One picture from outside our town house on a cold night. It was dark out but the phone app lets you use the phone's camera flash as a weak source of illumination. This is showing the first floor wall and kitchen hood vent, 2nd floor rim joist, and the master bedroom wall above it. This clearly shows thermal bridging, possible air leaks, as well as several areas where the fiberglass insulation batts are very poorly installed. Ever wonder where your heat gets out? Here's the answer, and from a pocket sized wonder that would have cost many thousands of dollars ten years ago.
Lance,
The resolution is surprising. Yupster probably has a good point as to it's use in air-sealing, but as a general guide to where heat is escaping it looks fairly useful.
In the late 80's the cameras were so expensive and bulky we used to borrow them from the National Research Council in Ottawa. They resembled the ones you see on the sidelines of professional sports games. At that point we really didn't know what to do when we did get the results - the distinction between heat escaping through different mechanisms not being generally well understood.
The robustness alone would make the pro cameras worth the investment for people in the field. This FLIR One is literally just a dongle that plugs into the bottom of a phone, not very robust at all. Between that and the more customizable user interface, a camera like the E8 would be a FAR better choice for the working professional.
On the opposite end of the scale, I think this little "toy" is perfect for the homeowner interested in doing some upgrades, and maybe a contractor who just wants to have an IR imager to use every now and then. It's definitely better than not having one.
A co-worker who was going through some home improvements for an energy audit/rebate program ran out and bought this same camera the day after I showed him mine. He absolutely loves it.
Yes, it wasn't that long ago that IR imagers were a thing of research and technology development. I assume that the cost of professional level imagers will drop considerably over the next few years.