Attic Upgrade Part 3 – Insulation

If you’re going to insulate your attic, you have to buy insulation. Seems like a pretty simple concept, until you have to decide how much you want to spend. The pallet on the left cost me $400 from Home Depot’s website, including delivery. The various bags on the right cost me $20 on Craigslist. The in-store price would have been $850 for the smaller bags, so I think I made out really well.

I have a total of 1500 pounds of cellulose – now I have to get it into the attic.

The delivery guys were great and put the pallet exactly where I wanted it in the garage. It just barely fit under the 7′ door. The pull-down staircase is toward the back of the garage, so the blower machine should fit in there just fine. I’m going to put a work-top at the height of the blower in-feed so it will be minimum of bending over for whoever I can bribe into doing the loading.

I have just a few more details to get done in the attic before I can start blowing the stuff in. I’m hoping to get all those complete tomorrow, then run the blower on Sunday. Home Depot said they have one I can use, but it’s first come, first serve – so we’ll see how that goes. If it’s not available, I’ll try to rent one.

With about $250 for the other materials besides the insulation, I’ll call this a $700 project.

I went to an online calculator to estimate the payback. Here are the results:

Image 2017-03-31 - 2754

It estimates I’ll save $250 per year, so the return is about 3 years – not bad. There are a number of places in the attic where the insulation is thin or non-existent, so I think I’m being conservative in my estimates. 

Fixing the air leaks – I had a couple of large ones around the fireplace – is probably the biggest improvement I could make. This calculator doesn’t take that into consideration. 

Finally, all the airflow I’m adding to the attic will keep the roof quite a bit cooler. This will add to the shingle life and also increase the solar panels output in the summer, as their efficiency drops somewhat with heat.

Update: I went back and read the fine print on the calculator, and it doesn’t take into account the reduction in cooling load in the summer. So probably the payback is less than 2 years. I’m now asking myself why I did do this before.

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