Is foam insulation worth the cost?
 

I just purchased a new home that is more than double the sq footage of my current. One of the things the inspector noted was my attic insulation was a little under the recommended amount for the location its in. My mortgage is already going to be $300/month more than I'm currently paying and since the house is so much bigger obviously the electric will be a lot higher as well.

I have already gone through the entire house and changed all bulbs to LED. Ive checked all doors and windows and they all have good seals. My next step is to replace the loose insulation in the attic with foam. Or keep it and have the top of the attic sealed with foam, whichever would work best.

Has anyone had this done to an existing home and if so how much did it cost? Was the utility savings noticeable and worth it?

Company I work for builds modular homes (not the same as manufactured/mobile)... We rarely use spray foam in any application. Usually build with 12" energy heel trusses and R-39 in the attic. If you don't have energy heels, just make sure the ends are as well insulated as you can get them.

You're talking about the roof, but you probably don't know the exact condition of your walls either. I'd highly recommend first getting a blower door test done to see where you are leaking.

I'd use the test results and focus on a better envelope by getting proper exterior air tightness/sealing.

Once you know you're airtight, then you can focus your efforts. You may find you need to add rigid insulation to the exterior walls as well.

If you are looking to have a well insulated home, you should install a good air exchange system with a heat recovery ventilator, etc because not only will it improve the air quality, it will help with heating and cooling costs.

If you do insist on spray foam, it can be better provided those steps are performed above. I say "can be," because spray foam installers don't always fill every crevice either and an air gap is an air gap. You have to be well-sealed one way or the other.

You'll probably spend 3-4 times as much on the insulation, but ROI in modern applications is much better at around 5 years. If there were any place I'd absolutely consider spray foam personally, it is in the attic.

I sell new homes and condos that use spray foam insulation and solar panels.

If done right (thick walls, on the rafters in the attic), your home will act like a cooler.

2000 sq ft home has ~ $20 electric bill... in Austin Tx which is hot as hell.

I just had 8” of insulation added in our attic last week. 2100sq ft home cost us $1250. It wasn’t spray foam though. It’s some kind of cotton candy type material.

My house is close to yours, a little over 2300 sq ft. If you'd be willing I'd love to hear how much (if any) you notice in your utility bill the next couple months.

Tell me more..

I wonder if that application would have the same effect in a more humid environment, say Florida?

50% of doing it right has absolutely nothing to do with the insulation itself and much more to do with the prep in proper sealing. You get the benefit, like me, of having a new home to work with where everything can be sealed, checked, sealed in missed areas, then sprayd. He isn't getting that benefit in an old home just by spraying some foam upstairs, but he can get closer if he takes the proper steps.

Just use asbestos.

Don’t forget to top it off with fine lead based paints

Smart.

I started throwing my crusty jizz socks in the attic. Don't know if it helps with the bills but the whole house always smells like mushrooms. So that's nice.

Make sure to coat it with antifreeze first, so it doesn't freeze and lose its power in the winter.

And apply with tongue

Yuck

The best and only method I would recommend

It had 2” of old insulation in it when we bought it. Unfortunately, we have only been in this house since April 1st so won’t be able to compare previous months.