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Should I add more insulation to my attic?


LinuxGuy's Avatar
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11-03-09, 07:27 PM   #1  
Should I add more insulation to my attic?

I posted some pictures taken from my attic here:

Pictures by theattic565 - Photobucket

The room directly under it is the coldest room in the house in the winter and the warmest in the summer. It might be due to poor ventilation, but maybe it could also be due to not enough insulation. The temperature in my attic was about the same as the outdoor temperature. Should I add insulation to my attic or is there anything else I should do? I live in Portland, Oregon and it does not get too cold or too hot here most of the time. But I plan to stay here a while (> 5 years) it it might make sense to beef up the insulation now if it will lower my heating costs.

 
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GBR in WA's Avatar
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11-03-09, 09:38 PM   #2  
I cannot read the thickness of the cellulose insulation chart. So I cannot tell the R-value to compare to your locale. I would change the flex ductwork to smooth rigid pipe with foil tapped joints and insulate and vapor barrier it. Do you have soffit supply air vents and ridge exhaust vents?
Be safe, Gary

 
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11-04-09, 10:04 AM   #3  
The thickness of the cellulose averaged between 10 and 16. I guess they did not do a good job of smoothing it out. Is cellulose as affective as the tradition pink fiberglass insulation? It's basically mulched newspaper and fiber right? I could buy the pink fiberglass insulation that comes in rolls and put that underneath the cellulose. Would that make any noticeable difference? Also, why would R-Value vary by location? Why should a house in Portland, Oregon have any less insulation than a house in Fairbanks, Alaska?

That ductwork you see, I believe is for the exhaust fans in the bathrooms, microwave oven, gas furnace / water heater exhaust, and clothes dryer exhaust. I would like to install a bigger clothes dryer exhaust because I believe the airflow is somewhat restricted, probably partially clogged with lint. Anyway, if all those pipes are for exhaust, why replace with more insulated pipe? Alternatively, would there be an insulation blanket that I can wrap around the pipes to better insulate?

Thanks for the advice!

 
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11-04-09, 10:46 AM   #4  
Hi LinuxGuy, several issues here so I'll just number them.
1. Cellulose is about the same r-value as fiberglass and a lot better at blocking air leakage. That is when installed properly and left alone. If it has been disturbed, it looses a lot of it's insulating properties, so you wouldn't want to install fiberglass under it and if it has been raked out and moved for other construction purposes it isn't doing as good of a job as it should. R-3.5 per inch when dense packed. Give it R-2 per inch where not. Bottom line, even with the insulation fluffed up, you still have some insulation up there, so adding more will not make a big difference.

2. Recommended R-values vary by location based upon heat or ac loads. Beyond a certain point they calculate the insulation costs more than you save. They are supposed to be projecting 10 or 20 years down the road, but who knows.

3. The ducts are a concern and you have several types. In a cold attic, a duct handling warm moist air will condense out water like mad. Add a bunch of lint from a dryer and you have an obstructed duct. Smooth metal ducts will collect less. Basically, you need to reevaluate what you have for ducts for each purpose to make sure they meet codes and and function properly. I don't have enough information to comment beyond that, but there are others on the board that may be able to help.

4. Last is, there is still a reason for that room being cold and I don't think the ceiling is the only issue. #1 for making affordable improvements is air sealing. Air leaks around chimneys, plumbing, electrical wiring and those fans or recessed lights is lost heat, plus it caused an equal amount of cold air to enter somewhere else. More details on the rest of the house will help us suggest other target areas.

Bud

 
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11-04-09, 04:41 PM   #5  
"I would change the flex ductwork to smooth rigid pipe with foil tapped joints and insulate and vapor barrier it. " --- because the accordion pipe is double the surface area inside to trap moisture as it blows by, causing mold inside the pipe. Especially if there is no insulation and vapor barrier to temper the different temperatures as the air goes through. Hot, moist air, plus cold, corrugated pipe = water in pipe. The water heater and gas furnace can share a double pipe duct (B-vent) where they go through the attic. These would not be insulated. The range needs it's own duct, smooth wall metal usually 6" or 7". The dryer need smooth wall metal, alone, and insulated and v.b., same reasons as the fan ducts. Except the first 8' can be metal flex, extra special type. The first 7" of insulation gets you 97% of maximum: http://www.enersavesystems.com/pdf/E...Insulation.pdf
Be safe, Gary

 
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11-05-09, 01:22 PM   #6  
Good point about the ductwork. The cold air outside the duct combined with hot air inside the duct would mean water in the pipes. I never use the indoor exhaust fans though so I might just replace the dryer duct for now. I guess I probably have enough insulation in the attic, there's definitely at least 7" in most places, but as soon as I get a ladder to go into the attic, I will ensure that the insulation is spread evenly.

Background on my condo, it was built in 1996 so it's not too old. The bathroom is still the coldest room in the winter and warmest in the summer -- not by much, but it is noticeable. I'll feel around and try to determine where most of the cold air is entering the room from. I have a feeling that the biggest source of heat loss in my house is the windows. But would the cost of replacing them ever pay off in energy savings? My worst heating bill in the winter from last year was around $50 gas + $50 electric (I run my house cold in winter, around 63 at night and 66 during the day and I shut off the furnace or A/C while at work). This year's gas rates are lowest in past 5 years. So no need to get too crazy with the insulation, but I want to cut my costs where possible without sacrificing too much comfort. Guess I like having an efficient home.

 
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11-05-09, 01:42 PM   #7  
Well, I'm over above the other Portland and you could have trouble heating for a week on those numbers. I've worked on homes that IF they turned the stat up to 65, in the deep of the winter they could shell out over $1,000 in a single week. Most of those homes the occupants have retreated to just a few rooms to survive.

With a cold bathroom check, as best you can, the pipes under the sink or if you have access the pipes under the tub or shower. When you look at these areas during construction, you realize that the framing allows air to move freely behind the walls, from basement to attic. That's the reduce energy solution to making the bathroom warmer. There is always adding more heat, but that goes the other way. Not sure how the room is constructed, but a quick fix is the shrink wrap plastic over the window. It may not be what you want in the long run, but it will help you decide if a new window will help. Most often, windows are the last thing to be changes as they have the longest payback.

Bud

 
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11-05-09, 06:01 PM   #8  
Turn on the bath fan, light an insense punk to find the air coming in. Use a rolled towel under the door when checking. As Bud said, anywhere a pipe enters or leaves the room- around bath fan/ceiling, light switch, box, shower head, lights above mirror, etc.
Be safe, Gary

 
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