Foam house insulation

I’m considering having foam insulation installed in a house built in 1955 without insulation in the walls. Has anyone done this? Did you save enough money on heating and cooling bills to make it pay?

I have to ask: Do you mean the blow-in type? Or putting in rolled goods behind the sheetrock? Or Rigid foam? There are a lot of products.

My parents had this done to their house decades ago, after the 1970s oil crisis. The contractor pulled shingles off the sides of the house, drilled two- or three-inch diameter holes and blew insulation of some sort into the wall cavity. This was in Connecticut, so they definitely saved money in the long run by doing so. I can’t say whether it makes sense for you in Arkansas to do the same thing.

Assuming you’re talking about spray foam, there are two basic types: open cell and closed cell. Open cell is cheaper but has a lower R-value and may require a vapor barrier depending on your climate. Closed cell is very expensive but extremely energy efficient and it serves as its own vapor barrier. IMO closed cell is an excellent value for attic insulation but may not be worth it for walls.

That said, if you truly have zero insulation in your walls, anything is better than the status quo. Even stuffing them with old newspapers will show a dramatic improvement in your home’s energy efficiency. (Note: don’t actually stuff your walls with newspaper.)

Given the age of your house, I recommend you ask your local utility company if they do energy audits. Many of them will give you a discount or even do them for free. It’s important that you take care of any air sealing issues before you insulate. A mile of foam won’t make a difference if you’ve got big holes in your house and gigantic single-glazed windows.

We did this many (guessing 20+) years ago, in conjunction with having the house re-sided. Our house was built in1926, and had no insulation in the walls.

I have often remarked that doing this is one of our best purchases. Our house holds its temperature very well, meaning that if we open up at night when it’s cooler and then close up in the morning, it’s often afternoon before we have to turn the AC on. When at neighborhood get-togethers others would complain about how high their heating bills were, I’d not participate. All the houses in the area were built at about the same time, and while we keep the house fairly cool in the winter, our bills were often half of what the neighbor across the street was paying, and her house was half the size of ours.

I had cellulose blown in to my 1969 home (1080 sq. ft), and also in my attic. There had previously been nothing. I have aluminum siding so they poked holes about every 16 inches at the top of the siding, and covered the holes with caps that they painted using my house paint. I think with vinyl siding they pull off a row of siding and snap it back on after. The caps look fine and are hardly noticeable.

I had it done I think 4 years ago. Cost I think $3000.

I made the decision to do it because there was ice forming on the inside of my bedroom wall (which is an outer wall). That was ridiculous.

I don’t know that it has caused my bills to go down significantly. We’ve had much more mild winters since the “ice wall” winter so it’s hard to tell. I doubt it has paid for itself yet, but it might pay for itself over a longer period.

My monthly gas (I have gas heat) and electric bills have not gone UP in that time. I use the budget billing (same cost each month regardless of use).

One thing you’ll want to do is compare cellulose vs. foam if you can. Have the salespeople give you a pitch for each. My guy gave me a great pitch for cellulose so I went with him right away.

Also, hopefully they advise you to do the work in the winter. If it’s cold out they can use infrared imaging to see cold spots and check their work. My guy advised this, and it really did work - once they did their initial pass he took me around with the infrared camera and showed me cold spots and had his team fix it.

Also friedo’s advice about the energy audit is spot-on.

One thing to check into is whether your walls are built with horizontal blocking, which may result in twice as many holes (one to fill the bay above the blocking and one to fill the bay below it).

You should check with your electric utility (and natural gas utility if you have that) to see what kind kind of energy efficiency incentives or rebates they have that might apply to insulation. Probably only applies if you use electric (or gas) heat, but in some places, those kinds of programs could pay a very significant part (as in, possibly up to 100%) of the cost of retro-insulating a house.

I’d love to do this, but my 1904 house has knob and tube wiring at least partially in the walls. Which would probably require rewiring the house, which would probably require tearing out a lot of the plaster and lath walls, etc. etc. etc.

Foam pumped into the walls through holes the installer drills. My MIL worked for a company that did this in the a980s, and had her house done, put they did not note the difference in utility bills.

We have a 70 year old double-brick walled home with interior plaster walls. I’d seen contractors using the low expansion foam injected through the interior on shows like This Old House and was interested.

I contacted three in my area, none would do the foam injection into my walls. Each one said that that “low” expansion foam is not “no” expansion foam and +40 year old plaster walls are typically brittle and there is good risk of them cracking. They did not want the liability to repair the walls if that happened.

It will be interesting to hear if you find someone and if so what guarantees do they give you if the walls crack?

The other variable you should weigh off is the cost savings (heating & cooling) versus the cost. I’m not saying it’s the case where you live, but in a northern climate (like Canada) +80% of the heat loss is through the roof. Doing things like walls and even windows don’t make sense from a cost savings perspective.

They do add perceived value for resale and maybe soundproofing etc, but from a strictly energy savings payback perspective they don’t (unless you’re getting a subsidy through your local utility). Meanwhile, the blown in attic insulation I did in paid for itself the first winter.

My FIL put 12" of fiberglass batts in the attic. We have sheet rock on the inside walls.

When I was considering my options I found a few websites that had “cost savings calculators” for thing like insulation, windows etc. to give you an idea of what’s worth it. You input your climate zone, your specific heating / cooling costs and they tell you the cost savings. They’re probably still around if you need help.

The big payback is definitely the attic. I had a contractor do it through Costco. It was the lowest cost option for me and took less than two hours. I think it was in the few hundred dollar range versus the $3000+ to have the walls done (or the $20,000+ to replace all the windows.)

I forgot to tell my wife I’d had it done, that winter she was paying the bills and spotted the comparison they show versus the same period for the previous year. She said “I think they made a mistake on the gas bill, look how much it’s dropped.” I told her about the insulation and we were both shocked at our decrease in consumption. Should have done it years ago :smack:

Yep, I’m blowing insulation in the attic this fall over the loose cellulose that’s already there. It’s less than 8" thick.

The walls are a poorly insulated as well. Old (60+year) faced fiberglass that’s basically useless. I doubt I’ll have the walls blown, but next year I’m going to tear off the crappy looking shakes and reside. When I do, I’ll wrap the house and then either use insulated vinyl siding, or put foam board under engineered panels.

The windows are awful. Shittiest vinyl replacement windows possible, and they were installed by idiots and/or assholes. The big rectangular window in my living room is actually slightly trapezoid enough that the sliding pans on either side don’t sit flush. How the hell you can make a rectangular window a trapezoid is beyond me.

I’ll probably either replace the siding in stages, or wait an extra year so I can replace all the windows at the same time.

I forgot to add, when we got blown-in insulation, the change in heating bills wasn’t super-obvious (after normal weather variation), but it did seem to really eliminate the cold spots in the corners and odd places.

Foam sprayed into walls makes future repairs and changes difficult. Is all your wiring up to date? Planning on adding, replacing doors, windows, etc? Blown in insulation doesn’t get in the way like that. However, it does settle over time in walls, you may have to top it off after a year to be fully insulated.

Whatever you do will save you money on utility bills in the long run, or maybe the short run if you’re in a cold area with no insulation in your walls.