Letters: March/April 2012
Diagnosing an IAQ Problem
I read about the problem of a reader in the Jan/Feb ’12 Home Energy (“Diagnosing an IAQ Problem,” p. 3). I also read Tamasin Sterner’s reply. I would like to say that I know and have worked with Tamasin and believe she is one of the best building scientists around and I think her reply is sound and right on.
Locating the source of a smell is often very difficult. In your situation, where new insulation, drywall, and paint have been installed, it would be difficult to identify which is the culprit.
The wall orientation is also an important factor. If one of the walls faces south, then the drying and heat and moisture movement could be to the inside of your home. Of course this is only a factor if the wall experiences a lot of sun or solar loading.
This is a method I’ve used to help identify the source and products that are causing odors. It is not hi tech but it works and is cheap and effective.
Cut out a small section of drywall and place in a zip lock bag. I use gallon size slider freezer bags with write-on strips. Take just the insulation from the wall cavity and place in a second zip lock bag, and finally take a piece of drywall and insulation and place in a third zip lock bag. Let the bags sit for a few days or weeks and open and smell each bag to see which one smells like the odor in the room. It is possible that it is a combination of products interacting with each other. Either way, you should know which is causing the odor.
Another benefit of opening the wall is to identify if moisture is inside the wall cavity as Tamasin mentioned.
Therma-View Infrared and Energy Consultants
The Upside of Downlights
I would like to offer another idea for fixing the overheating recessed-light påroblem that editor Jim Gunshinan mentioned in his response to the questioner in “The Down-Low on Downlights” letter (Jan/Feb ’12, p. 4). This is how I handled the problem in my home.
About five years ago I purchased a home that was built in 1976. It had inadequate insulation in the attic and 11 non-IC-rated recessed lights in the ceiling. I wanted to insulate the attic to R-49, but I couldn’t safely cover the recessed lights, since they were not IC (insulation coverage) rated. I considered building a foam box over each one, but knew that this could overheat the fixtures.
I had decided to install kits to convert them to pendant lights to get the lamps outside of the fixtures. I went to Lowe's to purchase the kits, when by a stroke of good luck, I ran into an electrician friend of mine. I told him what I was planning, and he had a better idea. He informed me that recessed lights come in two different types, new construction and remodel. He told me that I could install IC-rated remodel kits and then I would be able to insulate over them without fear of overheating. I took his advice, and even though I am not a skilled electrician by any means, I was able to change out all of the recessed fixtures myself and I did it without going into the attic. It was pretty easy, and at the time, I was able to complete the project for under $300.
Editor Jim Gunshinan replies:
I didn’t like the CFL floods that we first installed in our downlights either, even though they solved our overheating problem. And we couldn’t find a good dimming CFL flood. Our local Home Depot had a sale on Cree LED downlight kits ($39 each, still high). As you mentioned in your e-mail, these are for retrofits. After a little sweating and finagling, I replaced five of our recessed-can lights with the LED kits, and we are very happy with the dimming zability and the light quality.
The contractor who did our energy retrofit installed foam board boxes over the downlights from the attic side and blew cellulose over them. In our case, most of the air leaks in our house were happening though the old, inefficient can lights, so we wanted to air seal as much as possible; plenty of fresh air is getting through in other places.
This is a matter of personal taste. I wanted to use CFL lamps and have never liked the flood-style CFLs, so I installed white trim packages into the recessed cans to get good reflectance and then just used regular 23W CFL twisters. Since I have flat 8-foot ceilings, they look good, because you really don’t see the bulbs unless you are directly below the fixture looking up. And they do a pretty good job of lighting the areas they are in. Any screw-in lamp could be installed safely into these fixtures. For example, if I ever wanted to install a dimmer, I could use incandescent, dimmable CFL, or LED flood lamps.
After the new light fixtures were installed, I was very comfortable installing the R-49 insulation over them. I didn’t air seal the lights for two reasons. The IC-rated cans that I installed were very tight, not full of holes like many recessed cans. Also, believe it or not, my house is very tight; well below minimum ventilation level. So I didn’t want to make it any tighter. I don’t have mechanical ventilation in the house. I need to crack a window now and then as it is.
Benton PUD, Energy Efficiency Advisor II
Jim Gunshinan replies:
I have been inspired to replace my CFL downlights with LED kits from Cree. I discovered the wing nut adjustment option, and a few metal screws, to adjust the can to accept the new light kit. It was easy after the first one. Now I have five LED downlights and four CFLs. The LED kits were $39, though; a bit much, but not for energy geeks like us.
More Downlights …
I just read Jim Gunshinan’s response to a reader who asked a question about different lamps in recessed lights (“The Down-Low on Downlights,” Jan/Feb ’12, p. 4). I would like to add that on the inside portion of the recess housing there should be a sticker showing acceptable lamp/trim combinations, and there should also be wing nut that will allow the lamp socket to be positioned correctly for the lamp. Few people consult the information that is available to them right on the fixture. Many manufacturers also make trims that can replace the existing trim to make the fixture airtight. Homeowners can easily increase the energy efficiency of their home as well as update the look of their lighting. As always, consult the manufacturer’s instructions.
—Robert De Vries Technical Services
Nu-Wool Co., Incorporated
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