Wednesday, January 04, 2012

Insulation

Despite our new heat system our gas bills continue to climb. Montana is not known for its mild winters and the worst is yet to come. We've already put plastic over the windows and used great stuff on every gap and crack we can find, but the real problem is our lack of insulation. The insulation in the walls and attic is thin, only R7. The energy company recommends attic insulation of R49 for this part of the country. So yeah, we're losing a lot of heat up there.
Our energy bill is already up $100 over last month so we know it's going to be an expensive winter unless we do something, and soon. After doing some research we drove to Helena and bought ninety rolls of insulation. Total cost $920.

Our existing insulation did not come close to the recommended 16" deep
We used rolls of R13 to fill the bays then rolled R30 in the opposite direction
Insulating our attic was nothing like they show on This Old House. There were no smiling faces as someone cheerfully rolled out insulation in a spacious, well lit attic. We spent most of the time on our bellies stretching as far as we could into the eves of the house. Conversation is kept to a minimum because it's hard to understand each other with respirators on. The weather may be unseasonably warm for Butte, but that means it's fifteen degrees. Only a fool would be in our attic all day without base layer. No wonder we don't have our own tv show.

The attic now has a total R value of 50 which should greatly reduce our heating expenses. But the best part is that Northwestern Energy is offering a substantial rebate on upgrading our insulation. After their rebate and a tax rebate our out of pocked expense is only $330. The insulation should pay for itself in the first year.
Our energy audit also indicated that we were losing almost as much heat through the crawlspaces as we were through the attic. The energy company recommended R19 for the crawlspace walls and rim joists but since R30 was the same price per square foot we decided to go with the thicker insulation.
The west crawlspace is under the two bedrooms added on in the 70's. It's only 14" tall so it's a challenge to work in.
The height actually worked to our advantage because we did not have to run the insulation vertically. It fit perfectly when run horizontally. Per manufacturer' instructions we insulated not only the wall but also the floor 24" away from the wall so cold air can't seep under the wall insulation.

The larger crawlspace was easier to access but required a lot more cutting and furring strips to hold everything in place.
All this work has greatly decreased the draftiness of this leaky old house and I'm sure it will make our heat bill much more affordable. But it has also has convinced us to replace the wall insulation. We'll be tearing the sheetrock off the exterior walls, replacing the insulation and putting up vapor barrier.

But we will worry about that later. We'll be starting a fun project next.



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