Spray foam vs fiberglass batts
Is there anyone here that might be able to give me a direction on price in regards to spray foam vs fiberglass batts for the house my wife & I are building?
We live in South Jersey & we do have cold winters from time to time, but it’s not like we live in Minnesota or anything. I’ve framed it w/ 2×6 walls to get some extra insulation to begin with, but a friend of mine suggested foam insulation to be real energy efficient.
Anyway, I’m trying to determine how feaible it would be to use foam vs batts. I know foam is more expensive, but I have no clue how much more & I know how much you pros love people calling up for free quotes 😉
Should I be expecting to pay double or triple (or more) what it would cost for 6″ batts – and given the climate here, is that extra expenditure worth it?
Replies
A general rule for fiberglass vs. icynene is that icynene will be about 2x the price of fiberglass. In south Jersey, I think some of the benefits of foam will be less. The foam material is expensive but also there are extra labor costs such as cutting the expanded foam off from stud bays. Where you are using 2x6's, you might be able to avoid that. One thing that I really like about the foam is being able to do a conditioned attic by spraying on the underside of the sheathing. I assume you'll be doing A/C and having a conditioned attic will certainly help the efficiency of that system, and the heat if your running air for heat too. If you do a conditioned attic then you can lose all the soffit vents which cleans up the exterior.
go to icynene's website http://www.icynene.com and find some installers in your area and show them some plans and go to some fiberglass guys. They might not give you an absolute price until they see the framing but you'll get a number that is pretty close to what it will be.
If you have not started yet, you could always use structural insulated panels, SIPS.
I can't comment on your costs because I don't have estimates for the installation labour for fibreglass batts. Icynene prices include labour, so comparing materials cost alone will give you the wrong impression unless you're doing the work yourself and count your labour as a zero cost, in which case of course Icynene is over 5x as expensive. The other poster's estimate of 2x the installed cost for Icynene versus FG batts is believable.
As to the energy benefits, if you run the calcs, air infiltration heatloss is more significant than conductive loss through intact walls, and there's no comparison between foam and fibreglass for stopping inward air leakage. The real thermal performance and comfort level of a foam-insulated house would be very hard to duplicate with fibreglass for this reason.
As to the monetary payback period, that depends on lots of factors like the design and siting of your house. But energy prices are going nowhere but up and you only insulate your house once- think of it that way.
One of the big benefits that both foam and dense-packed cellulose share is the ease with which you can minimize/eliminate thermal bridging through framing members. This bridging can account for as much as half the heatloss in a 2x6 wall and can be dramatically reduced with methods like the Mooney wall. The only way to mimic this with FG batts is to use rigid foam either on the exterior or interior, which reduces the price differential quite a bit.
I recently priced the two for the house my wife and I are building for ourselves. It's about 3000 sq.ft. two story.
The price from our usual fiberglass installer was $3900.00. R-19 walls R-38 ceilings
The price from a foam installer was $11300.00. we've never used foam in any of our houses yet because no one seems to want to spend the extra. We're still considering it.
Just to follow up on the last post. You should look into energy star homes programs, on a new construction that could save you enough money to make the foam price easier to consider. They will also give you some free stuff like duct mastic, expanding foam guns similar to the hilti ones, etc. To pass their program you need to be a tight house, fiberglass is possible but foam is much easier.
2300 sq ft in Northern Maine
FG installed was 9150.00
Iso foam bids were 17000 (I think) and 28000. both installed as well.
The balance will buy us a lot of heat.
The balance will buy us a lot of heat.
It's not just the heat, it's the comfort level that is a whole nother level.
FG is wasted money, wasted once when installed and paid for forever over & over.
Joe H
"The balance will buy us a lot of heat."
But with the foam you will only have to buy it once. Look at what has happened to heating costs in the past year!
One of my friends is building a log cabin in northern Minnesota and had insulated the basement walls with the pink stuff. Last summer it came down and foam went up. Talk about a difference, all the heat ducts in the basement are closed and it is still warmer. Also the sound proofing is another benefit, we park the snowmobiles next to the walkout and really notice the difference.
Save the fiberglass for your next boat.
"One of my friends is building a log cabin in northern Minnesota and had insulated the basement walls with the pink stuff. Last summer it came down and foam went up. Talk about a difference, all the heat ducts in the basement are closed and it is still warmer. Also the sound proofing is another benefit, we park the snowmobiles next to the walkout and really notice the difference."
That's in Minnesota though. We don't have nearly the winters as up there. That's why I wondered if anyone from South Jersey (or familiar with it) had any insight.
How about dense-pack or wet spray fiberglass instead?
The cost-benefit analysis is better.
I use Corbond poly foam rather than the icy everyone else is quoting. It has nearly twice the R-value per inch of thickness at about the same price which runds close to three times the coist of FG batts. Depending on the hosue and your living styuler, the foam products when properly installed will let you spend only 60-80% as much on heat as the FG btts and allow you a far better comfort level. Another benefit most homeowners like is that the house is much more quiet.
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I can't speak to you regarding costs becuase foam is becoming much more standardhere in Minnesota.. It's not unusual to have bids within 50% of each other... Fiberglas is probably the worst insulator on the market but it can be a do-it-yourself project and that is attractive to those who only consider first cost..
Spray in foam does require equipment beyond the reach of do-it- yourselfers so there is labor involved that might not be needed in a do-it-yourself project.
Having said that fiberglas will freely allow air to flow thru the walls.. (after all it's used in furnace filters) thus you are requiring that the walls themselves are secure enough to prevent the loss of heat from pumping losses.. The exterior house wrap must be perfect. Sooner or later the tape used to seal the edges will give up. When it does count on a dramatic increase in heating costs.
Foam will seal the house nicely. Thus air flow thru the walls will not happen.. In addition it dramatically strengthens the walls.. The typical racking and creaking of wood that happens in wind gusts will not happen when you foam a house..In addition you will be amazed at how much quieter the foam house is than a comparable fiberglas house will be.. Sound just doesn't want to travel through foam.
Finally If you use a digital thermometer and compare the wall tempurature between the two insulation mediums,, assuming verything is properly done both ways there will be a dramatic differance between wall temps..
In my case the differance on a zero degree day was 15 degrees.
Last year with 1/2 of the house foam and 1/2 fibergas heating bills were over $500. per month during Jan. and Dec. this year it was $380/$360 in a mostly all foam house.. (this in spite of the increased costs of energy...)
Here in Minnesota I expect when everything is done that foam will easily save me well over $1000 per heating season..
Here's a tidbit to figure into your heat loss calcs - the DOE figures that in typical construction, 30% of heatloss is due to air infiltration, which foam can nearly eliminate.
Other questions I would ask:
How big is the house? (if your wall area is small in relation to your heated area, you may never recover the expense of foam...diminishing returns...)
How many years is the payoff?
Would this max out the budget?
What are the other advantages of foam?
Will I always be wondering what life would be like with foam?
Now take 2 weeks and think on it...and don't believe everything you read from people with something to sell.
I recently built a house in NW indiana and used the Icynene and couldn't be happier. It was considerably more expensive, at least 2x, but the results are impressive i.e. energy cost, quiet and overall comfort. If this is your own house, it is definitely worth the extra expense. If it's a spec home you'll have trouble recouping the cost. Good luck! -Dan
Has anyone ever heard of spraying in an inch of foam to seal everything up and then insulating the rest of the cavity with fiberglass?
My fiberglass installer told me about this option. I had never heard of such a thing before.
EJC,
I've heard and even on rare occasion seen it..
To me it's a band-aide approach. done to save a few dollars at the cost of higher heating bills later.. Yes it is better than no foam and no it's not as good as all foam..
If you watch the process then you'll quickly see how little is really saved in using that approach.
They Still have to suit up and get the equipment in and laid out so the intial set-up fee still applies. They use slightly less foam and that is the only real savings. (however now they need to buy fiberglas and thus any potential savings has long gone) The labor in spraying an inch or so of foam versis spraying the bay full maybe amounts to an hour on a whole job..
yes now they have to trim off the overspray (but chances are unless they are really meticulous and experianced they will have some that will need triming later anyway).
The time used to Trim off the excesss and bag it up is much less than the time it will take to go back and install the fiberglas so there is no labor savings that way..
Usually the reason it's done is the contractor doesn't have a place that will accept the foam trimings and thus he will be forced to haul them to a disposal place..
You might offer to let the insulation contractor use your dumpster and find out that the price becomes much better..
I have a foam recycling place about 20 minutes from my home so it isn't a problem.. Check into that option yourself.
If you haven't already started to build look into the SIP option.. far superior and actually cheaper!