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September 26, 2008
blown-in insulation savings
hey all,
I'm considering having blown-in fiberglass insulation put in the crawlspace below my townhouse roof. It's a standard 20x50 flat roof, and currently there is nothing there but dead space. I've gotten estimates of around $2100 for a 12-inch layer of insulation and two vents installed. This is supposed to give an R-38 rating. Anyway, has anyone who has had this done (Dave in Bed Stuy, I see you've posted on this) seen demonstrably lower heating bills? How long should I expect for the insulation to pay for itself? Any before and after numbers would be welcome. Also: the insulation guy I spoke with said a vapor barrier (i.e. plastic sheeting laid below the insulation) is unnecessary. Is that the case? Thanks to all!
Comments
Sounds like you had done exactly what I did...and yes, no vapor barrier needed. Maybe at some point I'll get around to comparing this year's heat bills with last to see how much gas I've used but I had mine done during the winter and I could feel an immediate difference in the top floor heat retention.
Posted by: daveinbedstuy at September 26, 2008 11:09 AM
hey DIBS, haven't had it done yet, was trying to decide if it's worth it. But you could feel the difference right away?
And why is no vapor barrier needed? Thanks!
Posted by: Frederick Law Homestead at September 26, 2008 11:24 AM
Would love to do the same thing myself. Can you give me the name of your roofer/insulation person?
thx
K
Posted by: HurricaneKate at September 26, 2008 11:49 AM
DIBS, do you know of any issues involved in using fiberglass as opposed to cellulose or rock wool? . One of my neighbors insulated their roof with cellulose and used Federal Conservation to do the work. They seemed satisfied with the work. What company did you use? FLH, which company gave you the bid? Thanks.
Posted by: kidbklyn at September 26, 2008 11:52 AM
I used Federal Conservation..$2.00 psf plus $200 each for the vents if I remember correctly. No vapor barrier because its not "packed" against the roof like batts would be
Posted by: daveinbedstuy at September 26, 2008 12:17 PM
I haven't had it done yet, that's why I'm trying to get some opinions. Federal Conservation as well, but they only do insulsafe blown-in fiberglass, not cellulose.
Posted by: Frederick Law Homestead at September 26, 2008 12:55 PM
FLH...why are you interested in the cellulose instead of the insulsafe? It may be cheaper, I'll grant you that.
Posted by: daveinbedstuy at September 26, 2008 1:30 PM
the guy at federal conservation said they don't use cellulose, that it wasn't as good. But I've read mixed reports, some saying cellulose is better. I'm inclined to go with fiberglass. No chemicals, lasts forever.
Posted by: Frederick Law Homestead at September 26, 2008 1:34 PM
No chemicals in fiberglas? Don't get any on your skin or you'll be scratching a while.
Posted by: denton at September 26, 2008 1:58 PM
I had this done in my house over 30 years ago. The Brooklyn Union Gas contractor was supposed to use fiber glass, but ended up using cellulose because fiber glass wasn't available.[Many people were installing insulation at the timed and there was a shortage]. I can't give you figures, but my heating bill went down a lot. I was told that two mushroom vents would be enough to avoid condensation problems and that a vapor barrier wasn't needed. As far as I can tell, that was correct--no condensation problems are noticeable. I was a bit concerned because cellulose isn't inherently fire retardant like fiber glass, it 's treated, but I thought that might eventually dissipate. However, when I had some holes made in my top floor ceiling several months ago, I took the handful of cellulose insulation that fell out and tested it (by trying to set it on fire). As far as I could tell,the fire proofing still works fine.
Posted by: Bob Marvin at September 26, 2008 2:35 PM
I had to attend a NYSerta class on insulation/weatherproofing for my job a few years back and they set up a little demo using different kinds of insulation in boxes set up around a light bulb with a thermometer in each box and we measured the differences in temperature over time. The box with cellulose in it came in first by a fairly clear margin. The test was low tech enough that it would be very difficult to rig.
I have never used cellulose for a multitude of reasons, most of them having to do with installing insulation in new construction, but if I were going to have someone retro-fit my own home, after what I saw, I would go with cellulose.
Posted by: Bond at September 26, 2008 6:27 PM
I did it. Used Federal. One issue is do you have any insulation up there already ?? If you do its a problem. To blow fiberglass on top on bats creates air channels and decreases R value of the insulation and creates air leaks. Its better to pull it all out and blow into a clear space so it packs better. (I found out the hard way. I have bats)
Federal did a good job but its very hard to get in touch with the guy. He finally came after many calls. He came back when I found a void in the ceiling of a room and blew more insulation at no charge. Good job overall once he came. I have no specific figures for you but my gut seems to say that the top floor is warmer in the winter and not as hot in the summer.
Have you thought about getting any energy audit w/ a blower door test ? Its around $400 and its part of a NYS program so the fee is refundable if you use a certified contractor. In addition, there are also other programs w/ more savings and financing available through NYS if you do more work. Its not bad takes a few hrs and includes check your furnace/water heater for efficiency and CO. The blower is the best part looks for air leakage in your home's envelope. Holes equal drafts and lots heat and AC loss.
Good luck,
Posted by: divemd at September 28, 2008 9:58 AM
Divemd - I had an energy audit performed by CEC but they only use cellulose and I'm leaning toward fiberglass (no termite concerns, no mold concerns, etc.).
Do you have any info about this NYS refund program and would it apply to my CEC audit if I have another company install the insulation or is it only applied toward the installation by the contractor you use for the audit?
Daveinbedstuy - you mentioned Air-Krete in a past post - I'm also considering this as well as my front wall is quite drafty (I can feel the wind in my living room in the winter).
Do you know anything about the costs and energy benefits of having it installed?
Posted by: hansdieter at September 29, 2008 12:50 AM
A few years back, I laid down rolls of fiberglass insulation in the crawl space of my 1900 row house. I want to mention that whatever I am saving in heat, I am sure I am paying in air conditioning. I am no longer drafty in the winter but I am hot as hell the rest of the year. Just something to keep in mind when figuring the costs/benefits of insulation if you personally utilize (aren't renting out) the top floor of your brownstone.
Posted by: bqe1970 at September 30, 2008 10:42 PM
I don't have the specifics. The program is called the High Performance w/ Energy Star Program. I am planning on doing a foam job in my basement in Dec. The contractor sent me a bunch of work sheets from this program w/ the incentives. Try the new york state energy star program web site it may all be there.
http://www.getenergysmart.org/SingleFamilyHomes/ExistingBuilding/HomeOwner/Participate.aspx
My contractor said that he has to submit the paper work to NYS and get the job approved before he starts the job.
Posted by: divemd at October 22, 2008 8:17 PM
bqe1970, you mentioned laying rolls of fiberglass. May I ask about the technique you used? I tried to get fiberglass from the roll in the roof space of my row house. And it was incredibly difficult. I am pretty fit guy, but moving about that space is tearsome. I could not back up at all. Maybe I will need a helper who would unroll the roll and I will just pull it into the position.
I also considered to take a radio controlled car from my kid and use it to pull rolls. :)
Posted by: bobjohn at December 29, 2008 1:40 PM
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