Floyd Avenue Energy Audit Results
Renovating a historic home comes with many challenges.
In our recent Museum District historic overhaul, we blogged about the challenges of demolition, salvaging original materials, rethinking old layouts and choosing finishes that honor the home’s history. Today we’re going to discuss the challenge of upgrading an old home with efficient and sustainable energy practices.
The first step to upgrading a home’s energy system is to find your baseline and see the current efficiency (or lack of efficiency) in the home. To do this, we do a blower door test to see how much air is getting in and out of the home. This give us the ability to re-test after the renovations to get accurate results.
Once we’ve done this, we have to start making decisions about the upgrades and methods we use. Again, historic homes and renovations force you to work around existing structures and materials, so it’s not a free-for-all like it would be in new construction. We consider the historic charm of the home and how to maintain that as well when we make energy decisions. We also have to consider cost and the return on investment.
This home had exposed brick walls both upstairs and in the basement. In a case like this, we look to spray foam insulation, because it adheres to the brick texture better than other kinds of insulation such as cellulose. We insulated all of the exterior walls of the basement in order to finish off this rom and expand the home’s square footage. Previously this unfinished basement had been used only for storage and laundry.
On the first and second floors, we had to open up all the walls for our new layout, so while we were doing that, we went ahead and put in spray foam insulation on all exterior walls as well. Generally, if you don’t have to open up an exterior wall, the return on investment to do so just for new insulation is negligible, but because we were inside the walls anyways, we went ahead and made the investment for long-term comfort.
In the home’s attic we used blown-in cellulose insulation, which has a good performance to cost ratio. Because we weren’t dealing with exposed brick in the attic, cellulose performs just as well.
One of the biggest energy losses we allowed in this home was to keep and restore the original windows. Again, when renovating a historic home, you have to weigh the historic charm with efficiency. In this case, we felt using the existing windows was the better decision and instead allocated dollars to other areas of the home that we thought would benefit.
Because of our door testing, we were able to compare the energy efficiency of the home before and after the renovations. On the table on the left you can see the “before” results and on the right are the “after” results. We brought the home’s annual energy use down by 11,000 kilowatts/year. That’s a huge improvement! The average home in Virginia uses 32,000 kilowatts, and this home uses just 18,000 and is nearly 100 years old!
This reduction in energy use is even more impressive when you consider that we expanded the livable space of the house from 1,400 square feet to 2,100 square feet by finishing off the basement. More square footage and less energy usage? That’s a win all around!