I recently replaced several bathroom exhaust fans in my house. During the numerous trips to the attic the blown-in insulation was compressed in several areas. I tried fluffing it back to original when done, but not with much success.
Any suggestions on how to restore the full insulation value? The house is only two years old so all of the other insulation is still in good shape. The areas that are compressed are pretty small in comparison the entire area of the attic.
Thanks
Replies
Rocky, Hope that wasn't fg insulation you were trying to fluff.
Suggest some bags of cellulose from HD or other big box store.Depending on over all depth, R-value of what you have, and energy bills, you may want to blow a layer over all of the insulation, burying floor joists and duct work.
Did you foam or caulk in the new exhaust fan housings to insure air tight fit? Do you have any recessed can lights?
Where do you live, what is R-value of current insulation? Reason I ask is that if you are going to go to the trouble of making some insulation corrections, might as well do it right and end up with an efficient attic energy wise. Hope this is helpful, Paul
Thanks Paul
I have never looked into purchasing cellulose insulation so was not sure HD carried it. The reason so much time was spent in the attic was that I sealed all of the exhaust fan with a mastic. I live just north of Portland OR, so the weather is not extreme, but does get cold once in awhile.
We do have recessed lights upstairs. I have not pulled any insulation back from them to see how they are installed. We always ASSUMED the builder put in the right material correctly, but have been disappointed a few times now.
Rocky, be sure the light cans are IC rated if you have insulation touching them. Re attic fan box, suggest a collar and good lid over box, with weather strip foam around mating surface of collar. You want air tight between attic and conditioned air. Also, I would examine all seams of duct system, boots, air handler etc. PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
Hi Paul and Rocky,
Rocky, I'm doing kind of what you did, 'cept I'm redoing a whole bathroom with fans and recessed cans. I was wondering Paul, if you suggest sealing all penetrations into living space with Great Stuff foam, or maybe a type of caulk for things like the lights and fan? My attic isn't nearly as tight as I'd like, it's always a few degress colder upstairs than in the rest of the house. I've got to go around and do a through check for air coming through. Rocky, good luck...
Erich
Erich,
First, the light cans have to be IC rated, meaning insulation contact is ok. Then, yes, seal the sheet rock to can seam, fan housings etc with Great Stuff, or if you want a less messy foam, there is a latex water clean up type at the box stores. I prefer it for indoor use. All penetrations should be sealed. Humidity in an attic from leakage below is bad news as well as an indication of wasted heat.
Look at the attic access, door seal, lid, pull down. All can be sealed with the right weather stripping. Pull downs are especially leaky, and need a hinged lid with a layer of foam board for insulation.
If you have forced air supply grilles in the ceiling, pull the diffuser ring down and see how large the gap is between sheet rock and duct.These need to be sealed with aluminum tape or caulk, before replacing the grille. Follow the same reasoning through out the house, ie., floor ducts over crawl spaces may have a large gap as well.
If your up stairs is noticeably colder, and you are heating it, then you may need more or better insulation...after sealing.
Also, if you have ceiling supply grilles, and ceiling return grilles, you can make the upstairs far more comfortable by installing a low on the wall return grille. This will pull the cold air off the floor, and help the warm mix better. We live in the lower 48" of our houses most of the time. Since heat rises, high supplies feeding high returns is kind of stupid, if you follow my logic. Hope this is helpful. PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
Paul,
Yes, very helpful, thanks for the time. I've got IC rated housings and, in fact, they're "Air Tight", a product from Progressive Lighting. I've got to figure out how to Air-Tight them though, the directions are a bit unclear, it involves silicone caulking some portion of the housing on the inside. Anyway, once the bathroom is done [taking for-bleaking-ever, the mantra of a lone amatuer remodeler] and things warm up a bit I'm thinking of taking all the insulation out and doing a through check for air leaks and then replacing it with better insulation. I've got FG pellets - tufts might be a better word - now and I don't think they do a very good job. Definately colder upstairs. Anyway, thanks for the input, it's really much appreciated.
Erich
paul could you explain to me what a "low" is on the return grill?? I have two, one on the upstairs ceiling and one downstairs in my living room about 3 ft or so off the floor. Can i block off all or part of the upstairs in the winter? thanks Frank
I only use my gun whenever kindness fails...
Frank, I don't know if you have two systems or one. However, here is a common situation. In the upstairs, the supplies are in the ceiling, and the return is also in the ceiling. The hot air enters a bedroom, moves across the ceiling (hot air rises) flows under the top of the doorway, and heads for the ceiling mounted return, usually in the hall. This procedure continues until the blanket of warm air finally satisfies the thermostat, which is about 5' from the floor. We live lower than that, unless walking. We sleep, bathe, watch tv etc. in the lower portion of the room, and our feet stay cold compared to the air 6-7' up. This is one of the drawbacks of a forced air ceiling supplied system.
Another problem is the efficiency of heating the air. It is easier for the transfer of heat into cold air than into warm air.With the return grille in the ceiling, we constantly send the warmest air back to the heat exchanger in the air handler, not the coldest air.
An improvement can be made to the system by installing another return, close to the floor in the upstairs, perhaps in a hollow wall or side wall/ceiling of closet. This lets the return pick up a lot of cold air from the floor, and send it to be heated. It also helps pull some of the hot air flow down to where we "live".
I used a closet wall in the hall, cut into the top of the closet through the ceiling and ducted over 2' to the main return in the attic. I put a false sheet rock ceiling about 10" below the original one, taped, mud, and painted. I put a filter grille low in the wall for the duct. Now, a very nice flow of cold air from the floor returns to the air handler, and the difference in temperature from floor to ceiling changed from 8 deg to about one deg difference. The run time to satisfy the thermostat is shorter since the air is better mixed.
re: your question of blocking off one grille. First, you should not restrict the return sq inches of the system. You can add more sq in. of return, but don't reduce the area. There are systems with hi/lo returns that have louvered returns the are adjustable. They are designed to operate with one season "hi" being open, and the other season with the "low" being opened. Did this clear it up for you? PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
I agree with the benefits of the lower air return.
In my situation, the return for the upstairs system was in the 3rd floor kneewall. Air from the 2nd floor ceiling vents cruised across the ceiling, up the stairwell to the return. The third floor was way too warm at the expense of the second floor. Installing a stairwell door with large open return grates at the bottom solved the problem by forcing the warm air layer further down on the second floor. Saw a big improvement in efficiency as well since I was now heating the cooler air near the floor, and the temp of the air in the ducting was also now much cooler so there was less loss.
Also, one could improve the situation by putting air vents at the bottom of bedroom doors and then keeping the doors closed.
You accomplished a "low" return with the door, and I bet the comfort level jumped immediately. Also, the low return acts as a trap for the hot air.Without the system on, the hot does not fall to the floor to go through the door vent to then rise to the third floor. Well done. PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
I have only one unit but two returns. are you saying i should move the upstairs one to a lower level? on the second floor? i see exactly what your saying about the returns and air moving from the vent to the return and not reallly heating the air... since they are the same height... thanks a bunch..
Frank
I only use my gun whenever kindness fails...
Frank, our Q and A's may be out of sequence, in any event, I think you have made the improvements suggested. Hope your family feels the difference in both air comfort and cost wise. PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
If it's just a few areas, either rake a little insulation in from other areas (I use a child's garden rake), or buy a bag of cellulose and distribute it over the area by hand.