Update on insulation

My insulation piece yesterday generated some questions so I thought perhaps I would get more detailed here. There are a ton of great resources available on the web and I’ll try to compile a few here as well as inform you from my experience.

First things first-rebates

One rebate I mention is a sale that Lowe’s is having currently where they will give you a $100 gift card if you spend $300 on insulation. Each household is eligible for 2 gift cards. The sale goes on until 11/29. (Their site is down so I can’t provide you a link to their site but it was in their adsheet.)

I also mention the energy tax credits. This is part of the recent energy bill that was passed into being and exists for 2006 and 2007. The cost of your energy efficient upgrades can count on your income tax statement as a tax credit. (This credit doesn’t approach the billions that oil companies get while they are extracting billions in profits from consumers, but it’s a start) It applies to energy star rated items, like insulation, windows, doors, etc. Click here for more info and make sure to ask your tax person.

One other place you can check for rebates on energy efficiency upgrades is your local utility. My local utilities give out plenty of rebates, which I have used plenty of times. Check with your local company to see what they offer.

The thing to remember is which company will appreciate your efficiency gains and check with that company. A new natural gas furnace or water heater would be the gas company. But a new A/C or fridge would be the electric company. For things like windows, doors and insulation you’ll have to check each to see who covers it, if you have more than one company like we do here in Iowa.

Second things second–installation

I had a plethora of questions asked about installing the insulation. I hadn’t thought about installation questions in my previous post because I’ve seen so many This Old House, HomeTime and other home improvement shows that this is old hat to me. (Between those shows and the History Channel it’s a wonder I got any studying done in college) But it’s not old hat to everyone and I should remember that. So here goes. This is what I know about insulation, which may or may not be right, because I’m no expert, that is for sure. But I did stay at a Holiday Inn last night. (Sorry, couldn’t resist the chance to slid that in there)

Vapor Barrier
If you are insulating a room you need to pay attention to the vapor barrier issue. If you are insulating a space that doesn’t have any insulation currently then you want to buy insulation that has a vapor barrier. Install the vapor barrier towards the living space portion of the house. The vapor barrier is supposed to keep the moisture in the house to prevent water from condensing in the insulation and ruining it, and your walls.

If you are placing additional insulation into a space (like an attic) where insulation already exists you want to use unfaced insulation because adding an additional vapor barrier to the insulation is unnecessary (the original insulation should have a barrier). If for some reason the original insulation doesn’t have a barrier you don’t want to install new stuff on top with a barrier that will cause water to condense at the barrier on the new insulation. Water is bad news for just about everything related to a house.

Installing insulation
If you want to add more insulation to existing insulation you can buy unfaced insulation and just put it over the top of the old insulation. There is no need to remove the old stuff. It’s that simple.

Additionally, you want to make sure to buy insulation that fits the space you are placing it in. If you are doing an attic this isn’t as critical because, in theory, you have unlimited space towards the attic space and you can buy the thickest you want. But for a wall it is critical because you don’t want to compress the insulation. If you compress the insulation it will lose it’s insulating properties. So if you have a 2×4 wall use R-11 or R-13. If it’s 2×6 use R-19. Don’t shove R-19 into a 2×4 space because you’re just wasting your money. The airiness of insulation is what causes it to be insulating and if you compress the insulation it won’t be airy anymore.

For example, check out the picture to the right. This is a picture of our upstairs living space. We have a story and a half house and when we bought it we ripped down the wallboard to insulate this space. (Unfortunately we ran out of money for dr10-30-06.jpgywall…but that worked out well for this picture…2 years later…)

What you see here is R-13 (white stuff) installed in the areas that are 2x4s, basically the walls and the ceiling. The brown paper insulation is R-39 which is installed in the kneewall areas where there is sufficient room available for the insulation. Behind the kneewall is the attic space that acts as the ceiling for the downstairs living areas. Between the joists I installed R-39 as well.

All the home improvement stores have huge charts up that will show you want to use for your area of the country and for the type of space you are trying to fill.

Another thing to remember is air flow. If you are installing insulation into a cavity that is on the underside of a roof you want to either install baffles for air to flow behind the insulation, or leave the insulation out far enough that air can flow under the roof between the insulation and the bottom of the roof. This air flow cools the roof and keeps your shingles from getting cooked on hot days. It extends the life of your shingles by at least twice what you can expect with no air flow. Here is an example of what I mean.


Air infiltration
You can insulate until the cows come home, but if you don’t keep the warm and cold air where you want them you aren’t going to get ahead much. So, when you are insulating a space make sure to look for any holes that poke through the area and fill the holes with caulk or insulating spray foam to stop the air leaks. Plumbing pipes, electrical pipes and vent pipes are common culprits. Insulate (or caulk) around the pipe first to stop the air leak by plugging the gap between the wood and the pipe. Then cover the area with insulation to stop the temperature passage from the outside wall.
(Click here for example pics from the manufacturer)

They call this stuff Great Stuff and it really is great stuff.


Honestly, that’s all there is to know. Installing insulation is easy. Usually people try to make it seem harder than it is, which is a normal human tendency, but the basics aren’t hard at all.

I have some links below that can help you out even more.

This Old House (great site)


Simply Insulate (also great)


3 responses to “Update on insulation

  1. Pingback: GroovyGreen.com - Start Today :: Save Tomorrow : Blog Archive : Bob Vila ain’t got nothing on me

  2. You are a man of many talents – while I on the other hand have only now found the time to update your blog address on my site.
    Happy homeworking!

  3. Tuco–

    Your too nice t me. Anyone can do it. It’s almost as easy as riding a bike!

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