Air Infiltration, Proper Ventilation, and Air Sealing

Infiltration

Air Infiltration can be one of the main causes of energy loss and higher utility bills in existing homes.  A leaky home allows winter cold or summer heat a way into your home and the climate controlled air from you HVAC system a way out.  This causes your HVAC equipment to work overtime in order to keep your home at your prefered thermostat set temperature.  AEA auditors use a blower door (pictured below) to measure the leakage rate of your home. 

The home is depressurized by the blower fan to accelerate the leaks so they are easily detectable.  Depressurization pulls outside and attic air through infiltration points giving a flow that you can feel coming through cracks, holes, etc.  The auditor will calculate the Building Tightness Limit of your home to see how close or far your home is away from the acceptable tightness.  By using the infiltration rate and the volume of your conditioned space AEA can determine the natural air changes of your home.  If the home is leaky then air sealing is a simple way to save on your energy bills.   

 Proper Ventilation

A home that is too tight can be a health and safety issue, as well as an energy waster!  A home that does not have proper ventilation can have issues with humidity, moisture, stale air, and your HVAC equipment may cycle on and off more often than necessary.  This constant cycling on and off of your air conditioner or furnace not only increases energy bills, but will also prevent your home from attaining proper comfort levels.  In this case, installation of mechanical ventilation (for example an air cycler, ERV, or HRV) will give your home proper and controlled ventilation according to its size.

Air Sealing

When a home is leaky, air sealing infiltration points is a necessary and simple fix.  Air sealing can be a do-it-yourself project in most circumstances.  If you are not comfortable doing the improvements or your home is extremely leaky and some infiltration points will require a contractor to fix, make sure you find a contractor that is experienced in air sealing and weatherization.  An air sealing contractor should have a blower door set up while doing the improvements to make sure they do enough sealing to reach appropriate ventilation rates and also so they do not tighten the home to levels that may be unsafe. 

Common Air Sealing Areas