Part 2: Air Sealing and Insulation Improvements to SACE’s Asheville Office

Guest Blog | January 15, 2014 | Energy Efficiency, Energy Policy

This is the second post in a three-part series detailing energy efficiency upgrades to SACE’s new Asheville office. Read the rest of the series here or watch this video for a virtual tour!

A GO team member trims air sealing foam around a duct supply vent before replacing the vent cover.

The audit at our new building revealed plenty of opportunities to save energy at our new Asheville office. The final two posts in this series detail how we addressed recommendations from our audit…and then some! These upgrades have drastically reduced the amount of energy used  and improved indoor air quality in the office. We’ve already seen a decrease in our monthly utility bills in our first two months, which we will continue to track.

Heating and cooling account for between 32-52% of building energy use, and we already knew our building was leaky and under-insulated, so air sealing and insulating were our top priorities.

Air Sealing

Before installing insulation, we first had to seal air leaks. While insulation works like a heavy winter coat, stopping energy loss through conduction, it doesn’t stop air flowing through gaps, cracks and holes (or convection). Both of these techniques work together to reduce the amount of energy needed for heating and cooling. The Green Opportunities team found air leaks around doors and windows, holes drilled for plumbing and wiring, outlet boxes and duct returns, and anywhere that two systems joined (like corners and where walls and floors meet). Luckily, air sealing is one of the easiest energy efficiency upgrades to do—using air sealing foam and caulk to fill in any holes and cracks.

Newly installed insulation, its a beautiful thing!


After air sealing was complete, it was time to insulate the basement and attic.  Rolls of fiberglass insulation were installed in the floor above the basement to an R-value of 19 and several inches of cellulose were blown into the attic bringing it up from an R-10 to R-48. A radiant barrier was installed in the attic to keep heat from radiating into the attic from a hot roof in summer. The barrier looks a lot like aluminum foil and is stapled to rafters so dust can’t collect and ruin its reflective qualities. This made a huge difference immediately, dropping the ambient air temperature in the attic from 124 degrees to a tolerable 90. A simple hatch cover built from rigid insulation board air seals and insulates the attic stair opening, another inexpensive and easy way to save energy in the attic.

A fresh coat of mastic seals all seams on our air handler cabinet.

HVAC Air Sealing and Insulation

The same process of air sealing first, then insulating, was carried out on all heating ventilation and air conditioning (HVAC) systems and duct work. Poorly sealed ducts leak conditioned air and pull unconditioned air (from the attic or basement) into the building. Most of our ductwork had insulation, but wasn’t air sealed at connections with mastic, the gooey, non-hardening material that effectively air seals ducts over time unlike duct tape. A licensed HVAC professional tuned all air conditioning and handling systems ensuring they were running well and changed all the filters. Malfunctioning air handlers and filters clogged with dirt and dust can waste a lot of energy, so make sure to have your systems tuned every year and change your filters at least every three months. We also insulated the water heater tank and first five feet of hot water piping.

In our next post we’ll talk about going beyond the basics of air sealing and insulation to the advanced energy efficiency upgrades we undertook at our Asheville office, so stay tuned!


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