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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
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2003-10-28          67377


No, this is not a scam.

In the current "Stickler" thread the issue of energy consumption for Mark's house came up. I wanted to offer up a tip that may help save some energy.

When we built our house we did everything we could to make it as tight as we could. When the house was complete an energy auditor came out and did a blower door test, certifying our house as a "super good cents" house which should mean low electric bills. The house had a 0.30 ACH (Air changes per hour) rate which is very good.

In spite of all this planning and certifying our bills were consistently a lot higher than projected.

We have over 60 recessed light fixtures in our house. These were all supposed to be Air-Loc fixtures to keep air exfiltration from occuring, but they instead installed Air-Loc READY fixtures. When I held a smoke stick near the fixture I could watch the smoke rise up through the fixture.

The manufacturer of our fixtures, Juno, sells gaskets that are made to seal Air-Loc ready fixtures and make them Air-Loc fixtures. These gaskets are dirt cheap - less than $2 each.

When I bought and installed these gaskets our electric bill dropped by 20%/month. That was like a two-month payback, and my wife has commented that the house feels a lot less drafty.

So, if you have recessed light fixtures this is something to look into.




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JAZAK5
Join Date: Jul 2003
Posts: 276 coxsackie,ny
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2003-10-28          67383


excellent tip!!!! are these lights incadecent or flourecent ....


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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
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2003-10-28          67384


These are mostly long-neck halogen fixtures. The only exceptions are the wet area fixtures in the bathrooms that are incandescent. I should mention that the wet area fixtures were a no-name brand so I just caulked those around the perimeter where the fixture pokes through the ceiling sheetrock. ....


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Chief
Join Date: Jul 2003
Posts: 4297 Southwest MiddleTennessee
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2003-10-28          67387


Laying an R-38 layer of insulation in the attic will make a big difference as well. Saved a bunch on my electric bill doing that. I also never use the heat pump when the outside temp. is below 35 degrees. I use the woodstove or kerosene heater downstairs. And the big tip for some free and easy heat is that I park my 4410 in the basement after several hours of hard running. Definitely puts out some heat. ;-) ....


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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
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2003-10-28          67388


Insulation is very important but it doesn't stop air movement. We have cellulose insulation, R21 in the walls and R43 in the attic so I was very surprised at the difference the air-loc fixture gaskets made. ....


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AC5ZO
Join Date: Jul 2003
Posts: 928 Rio Rancho, NM 87144
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2003-10-29          67401


Some recessed light fixtures require an airgap to the insulation or they will overheat. Some that I installed a few years ago required a clearance of 6" or so. Please check the types of fixtures that you have before you put any insulation over them or seal them up. ....


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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2003-10-29          67412


Around here most energy efficient buildings would have vapour barriers above the ceiling that I think would prevent the problem. Maybe it is a heat issue and codes require air space above fixtures. That might prevent vapour barrier from being laid on top of them unless structures were build above the fixtures. If I had a choice between paying carpenter hourly rates or buying 2-cent gaskets I'd likely go for the gaskets. Having much space for hot air to escape from the ceiling to the attic sure would run up the heating bill. ....


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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
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2003-10-29          67422


Our house has vapor barriers but that doesn't solve the problem. The heat loss is caused by air exfiltration through the penetrations cut in the sheetrock and vapor barrier for the fixture. You can't cut those penetrations tight enough to eliminate gaps through which air can leak.

AC brings up a good point. In my case the fixtures were all approved for direct contact with insulation, but if you're retrofitting you need to check this to prevent a fire. ....


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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2003-10-30          67519


I was trying to figure why the ceiling wouldn't have been built and vapour barrier laid over the whole thing rather than cutting panels out of the barrier for the lights. I can think of several reasons such as the barrier tending to tear where it goes over the lights or maybe disturbing overlap between widths. Just trying to fill in some gaps in my building technique knowledge here. I always thought having continuous barrier was desirable. ....


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kwschumm
Join Date: Feb 2003
Posts: 5764 NW Oregon
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2003-10-30          67558


Tom, are you thinking that they would build the ceiling and install all the light fixtures and then install the vapor barrier on top of the whole thing before insulating?

That seems to make some sense and I'm not sure why they don't do it that way. One drawback may be an air gap between sheetrock and the vapor barrier that would lay on top of the ceiling joists, but I'm not sure if that would be a problem or not. Another problem may be the fact that putting 12-14" of insulation on top of vapor barrier may cause the vapor barrier to tear through, especially as it ages and becomes more brittle.

I know I wouldn't to work in attic built that way. ....


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AC5ZO
Join Date: Jul 2003
Posts: 928 Rio Rancho, NM 87144
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2003-10-30          67567


It sounds to me like there are significant differences in the construction methods. You guys live a lot further north than I do. Insulation on houses here is not taken as seriously, I suppose. Most of my houses have used roll insulation with an attached vapor barrier. But there are big gaps in the coverage.

For example in my former California residence, the recessed lights required an 6" airgap according to the installation instructions. With only about 8" of insulation in the attic in the first place, that amounts to a big hole in the insulation that is a square about the same size as the joist spacing. That section not only leaked air at the recessed fixture, but the only separation between the living space and the attic air was a 5/8" gypsum board. That same house had no insulation in the exterior walls.

In NM it gets a bit colder. More attention is paid to insulation, but there is still little finish or closure work done around recessed lighting fixtures. Ken is certainly right that using gaskets to seal up the airflow is a benefit. I have used caulking before, but that is a problem if you have to remove the fixture for some reason.

Another thing that I have done in the past to narrow the airgap around recessed fixtures is to cut a piece of 10" round steel duct and place that around the fixture. That provides about a 2" airgap and will keep insulation from closing onto the fixtures and overheating them. This also allowed me to have a much smaller uninsulated patch. Fixtures that are rated for direct insulation contact would solve all of these problems. But, it occurs to me that places like Lowe's and Home Depot may stock different types of fixtures for different areas and codes.

Recessed fixtures in my old house in NM had holes directly through the metal. Heat loss wasn't such a big problem but yellow jackets were. With holes about 5/16 through the metal and into the attic space, the bugs would come right through these fixtures and into the house. You could put gaskets on the rims, but the holes were for ventilation and were a real PITA. ....


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Murf
Join Date: Dec 1999
Posts: 7249 Toronto Area, Ontario, Canada
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2003-10-30          67573


Theres a local company up here that has a neat slant on home building, the houses are built in a factory in pieces small enough to be trucked down the road then bolted together on site.

The really different part about it though is that they build the house inside-out sort of, after the wall is framed the first thing they put on is the drywall, then they put in all the windows and electrical, from the outside, they they use a sprayed on vapour barrier, then they put in the insulation, then they put on the housewrap and finally the outer skin.

Apparently by doing it this way the structure is VERY well sealed since there are no perforations in the vapour barrier. Also, since the wood framing is on the inside of the vapour barrier it tends to swell and shrink less seasonally then if it was not sealed in.

Best of luck. ....


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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2003-10-31          67608


The link below goes to an article (.5M Acrobat) that describes some problems in Northern Climates. The problem is as much moisture from condensation as energy efficiency. Modern building techniques here go to a lot of trouble to ensure an intact barrier.

What can happen is that moisture still goes through some types of ceiling material or seams, and the air is warmer than the outside. It is trapped under vapour barrier but will migrate around and exit through any opening that isn't lower than the barrier. One problem is if it percolates through insulation it cools, moisture condenses in the insulation, rots wood structural members etc. I don't imagine there is this type problem in your area but that's what I was thinking of. What I am familiar with is intact barrier with wide overlap of the seams with insulation on top, and the edges are tucked around structures at the ends so the barrier goes down. Murf mentioned spray on barrier, which I think is the modern preferred method. But I'm just blabbing and it's easy for a person to sound like they know more than they do.

It's curious to note that the same government agency that provides the article had an energy efficiency grant program for older homes during the late 70's. The program subsidized contractors who did things like blow cellulose insulation into flat roof structures and put UF foam into wall cavities--on structures that lacked vapour barriers. Well, the victims of that program gassed themselves inside their houses; had their rafters rot and their property values crash to below 'handymans' specials.' Some program! ....


Link:   vapour barier article in Acrobat

 

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