Improving the Thermal Envelope

I can tell that the hours I've spent in my attic have made a difference in the temperature of my house. For example, 2 nights ago the temperature dropped to 28 F. Normally on a night like that with the heat set low (set on 58F - I like to sleep cool under my blankets and comforter) the temperature will drop 10 degrees overnight. This time it only dropped 4 degrees and I haven't finished with my first layer of insulation yet. I've got about 15 joist bays to go.

The photos from my infrared camera also show the difference. This way you can actually SEE the difference.

Infrared photo of my stairway ceiling before air sealing around the sun tunnel. 

Now look at the difference afterwards. I have not put down a layer of insulation in front of the Sun Tunnel yet because I just foamed it. The camera in both photos is not calibrated to the same temperature, but you can still see where the warmth escapes. And you can see that the area around the Sun Tunnel no longer transmits heat.

The center circle is the Sun Tunnel itself which is not insulated at all. It is basically a transparent dome surrounded by a tube of very shiny aluminum to transmit light to dark areas.

This photo shows a soffit in my kitchen before and after insulation.  Again, the camera is not calibrated the same because I don't know how to do that. But you can still see that there is much less heat transfer in this area.

Tangled Up in Blue - Blue Jean Insulation, that is

Stacks of UltraTouch Denim Insulation from Bonded Logic

I've been working a little bit each day on the insulating my attic before it gets too hot to work up there. If you have been reading my blog, you would know that my absolute favorite insulation is mineral wool insulation, the two main brands are Roxul and Thermafiber. It's made from either melted volcanic rock - basalt, specifically, or from slag, a by-product of making steel so you could imagine it is fire-resistant. It is also relatively dense insulation and reduces transmission of sound. BUT if you are going to spend hours and hours crawling around in the attic with this type insulation, you have to be prepared to ITCH. I just could not face that. I had enough of it last year on John's house.

So I picked denim insulation. The best deal I could find was from Home Depot online. I ordered 2 pallets for 24 bales of UltraTouch insulation. Each bale covers 48 sq ft. It's 5.5 inches thick for an R-value of 21. It took about 2-3 weeks to arrive and was delivered to my home for a charge of $55 which I thought was a bargain. It has been a delight to work with. It's easy to tear and install, doesn't itch at all, but it is very dusty. Despite wearing a mask when I am up there, I still sneeze some blue fibers out afterwards.

Here's the current state of insulation.

You can see that insulating at the far end of the rafters will be a serious pain. I need to install some baffles so the insulation won't get into the soffits. That I dread as well.

To show you the effectiveness of this layer of insulation look at the before and after infrared photos of the ceiling fan in one of the bedrooms.

Before air-sealing and insulation above the ceiling fan

After air-sealing and insulation above the ceiling fan

I think the purple area (the cooler temperature) on the ceiling after the insulation was installed is where a beam crosses the ceiling joists. I thought I stuffed the insulation underneath there, but apparently not. I will go back and get it. That's a significant advantage of having my Flir One infrared camera. It is nice to be able to check of your work.