How an Energy Audit, Some Caulk and Insulation (Total Cost $1175) is Saving Me $1000... Per Year.
This is the story of how an $1175 investment in improving the energy efficiency of my home is saving me about $1000 per year in energy costs, and has made my home much warmer and more comfortable in the process.
Last May I had a home energy audit conducted by Flemming Lund of Infrared Diagnostics in Sudbury, MA. The results weren't entirely surprising; I didn't expect my aging suburban home to be completely leak-free and perfectly insulated. Nonetheless, the energy audit was extremely useful in pointing out several actionable, high-ROI steps that I could take to increase the energy efficiency of my home.
Next step, equally important: I got down to it. I installed blown in cellulose insulation in areas where it was deficient, air sealed cracks and gaps, replaced old weather stripping, and then had a follow up energy audit to assess what kind of progress I had made. The pictures below are from the two audits, and show just how much of a difference the work I had done made -- you can almost feel the increased warmth and comfort of the house where blue spots turned to red on the infrared images.
Although Flemming calibrated the infrared camera to account for temperature differences between the two audits, It's worth noting that the outside temperature during the first audit was 50 degrees Fahrenheit and 38 degrees Fahrenheit during the second audit.
The following photos will take you through the steps that I took to improve the air sealing and insulation of our house. Blown in insulation was all installed by hired contractors, as was much of the air sealing work. However, many of the most significant improvements were made by myself -- looking back over the initial audit report, I simply retraced the steps on a cold day, found air leaks by hand (literally) and sealed them with a caulking gun. We'll start there.
Here are just a few examples of where I did air sealing work:
Aside from the very cool infrared images of improved insulation (posted below), perhaps the most valuable information gained from my follow-up audit was that these simple air sealing measures reduced my home's air infiltration from 0.87 NACH (natural air changes per hour) during the heating season to 0.42 NACH, and I have continued to make improvements since the second audit.
My air sealing work and the benefits it reaped confirmed my long-held belief that air sealing should be step one in improving a home's energy efficiency. It's cheaper and easier than an insulation upgrade, and helps to ensure that insulation will remain effective (if air is permitted to move through insulation, it loses r-value). It also goes to show that simply hiring a contractor to get the job done may not be the right course -- in my case, I think as much of the benefit came from simple things I did as from what the insulator did.
Still, once air sealing is done, improving insulation makes sense and can add to the benefit by helping your house retain heat. I'll let the following images speak for themselves:
Although insulation isn't necessarily the first step you need to take, we notice that there are no longer cold spots on the walls that create uncomfortable areas in the house. As a result of our upgraded insulation, in addition to our air sealing work, the house is more comfortable, takes less time in the morning to heat up when the programmable thermostat kicks in, and our utility bills are much, much lower.
Having taken these steps, we've also come to realize that there is no silver bullet: improving the energy efficiency of our house is an ongoing process -- there is still much to be done. The follow-up audit showed that there was still much room for improvement, and we have since taken steps in that direction. Some examples of where we initially fell short:
Although the follow-up audit pointed out some problems that I missed during the upgrade, as well as some new ones that were overlooked during the first audit, it was also helpful in confirming that much progress had been made.
So what's the payback time for these improvements?
I will note that my gas utility, National Grid, had a program that paid a rebate of 75% of the cost of the air sealing and insulation, which made something of a difference.
That said, the numbers are staggering: