The most important “Green Feature”, Not just a lot of hot air!

Many home owners ask me what the most important green feature would be to implement if funds were limited.  Is it solar thermal, photovoltaics, a green roof…  My answer is not the most exciting, and it is tough to show off to friends and family, but it is extremely important to any efficient building: controlling air infiltration.

Heat loss and heat gain are the leading contributors to increased utility bills and decreased building efficiencies.  When an HVAC system has to work harder to make up for these losses, then even the most efficient system will not operate as cost effectively as it should. The first step in any green building should be to stop the losses.

First, to stop the bleeding, we need to know where the wounds are.  I suggest anyone wanting to improve the efficiency of their home, to start with a simple energy analysis.  This can be done by hiring an energy inspector which performs a blower door test along with thermal imaging.  These tests are very affordable and have a very good return on investment.  A blower door test pressurizes the building so that if there are leaks, it will be forced to do so.  The thermal imaging helps define where these leaks are occurring.

Once the problem areas are isolated, it is important to come up with a strategy with your builder on how to address each issue. Solutions can be as simple as caulking around exterior windows, or insulating and installing seals on your attic access panels, or fixing a damaged fireplace flue. Sometimes more intrusive solutions may including adding insulation to an attic space or filling gaps within the wall assemblies.  A knowledgeable contractor can help you make your house air tight with the right planning.  It is important to re-test the home after the corrections are made to assure the problems have been fixed.  Ask your inspector about re-inspection charges, they usually have a reduced rate for the follow up inspection.

Another thing to consider when making a home airtight is indoor air quality.  If your house tests with a low ACH (air changes per hour), then an HRV (heat recovery ventilator) or ERV(Energy recovery ventilator) may be required to maintain proper fresh air ventilation. A balanced fresh air ventilation system will improve indoor air quality and comfort.  HRV’s and ERV’s increases or decreases incoming air temperature, depending on the time of year, to reduce HVAC load.  ERV’s also help maintain proper humidity of the home and is recommended in heavy heating areas.

Once the house is air tight, now it is time to focus on other green features like solar thermal or photovoltaics.  Otherwise, as may grandpa would say, “it’s like perfume on a pig”.