Air Infiltration Inside Your HVAC Closet

Much of our home’s heating, cooling and overall comfort is lost through infiltration; air leaking into our conditioned space (the area we live in). These frequently unseen holes add to your HVAC system load while increasing your power bill. Many areas are easy to find, such as around windows, doors, plumbing, electrical penetrations, light switches and wall outlets and are simple to seal with some caulk or foam sealant. Unfortunately, this is not the case with all air leaks.

According to a report by the Oak Ridge National Laboratory and Pacific Northwest National Laboratory, a homeowner can save 10 – 20 percent on heating and cooling costs just by sealing up all those air leaks.

Some homes have HVAC systems located inside an indoor cabinet or closet (see picture). While this may be a convenient place, it’s also an ideal place for air infiltration. A large hole is created when contractors run the ductwork during installation, leaving a gap that can be 3-5 inches wide and the length of the four sides of your ductwork.

Once the hole is exposed, attic air can go directly into the unit causing it to run inefficiently. Also, your return air grille (a connection to ductwork that allows air to return to a heating and cooling system) is often located directly under your unit cabinet and will pull unconditioned instead of conditioned air into your home. Additionally, your thermostat is typically located near your cabinet and the temperature around it will be closer to the attic temperature instead of the rest of your home, resulting in your unit running longer.

An easy fix to this problem is to cover this gap with commonly used materials such as plywood or foam board. Sealing the hole with one of these options and adding insulation is the best way to help close off air infiltration.

To identify problem areas in your home, take advantage of our energy audit program. The Advanced Audit is $100 and the Basic Audit, which includes everything except the blower door test (which is a great way to identify air leaks in your home), is $75. Either audit cost is refundable after the member makes the suggested improvements identified by our Energy Services Representative and presents receipts. Members have up to one year to complete the recommendations in order to be eligible for the refund.