Many homeowners experience energy loss in their homes due to gaps around windows and doors, hidden leaks in attics and basements or crawlspaces and a lack of insulation. A home energy audit can pinpoint the source.
Air leaks cause a lot of headaches for homeowners during the summer and winter months. Gaps around doorways and windows, cracks in the foundation and and a lack of insulation all contribute to drafty homes and high utility bills.
Common locations for air leaks
Some leaks are easy to find. For example, you can check for drafts by feeling around your window and door frames, light switches, recessed lighting and around the fireplace.
However, hidden air leaks are most likely responsible for most of the problems. Any holes or cracks in the structure of the house can cause warm air to spill out during the winter or hot air to enter during the summer. These leaks cause your HVAC system to work harder, which will increase your utility bills. Many ducted heating systems also have leaks that contribute to the problem.
Why hire a professional to locate the air leaks?
Although you may find a significant number of air leaks yourself, the best way to assess your home’s efficiency is to have a home energy audit conducted by a trained technician. BPTC will perform a thermographic scan, which makes weak spots visible and reveals over- or under-insulated areas, and the blower door test, where a doorway seal and fan are used to look for sources of drafts, heat loss or air infiltration.
Additionally, BPTC will pressure-test your ductwork to determine how much energy is wasted every time the furnace or air-conditioner runs.
If you’re buying a new home, consider having an audit performed as part of your home inspection.
The Blower Door Test
A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. The auditors may use a smoke pencil to detect air leaks. These tests determine the air infiltration rate of a building.
Blower doors consist of a frame and flexible panel that fit in a doorway, a variable-speed fan, a pressure gauge to measure the pressure differences inside and outside the home, and an airflow manometer and hoses for measuring airflow.
A duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct leakage tester consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow. The combination of pressure and fan flow measurements are used to determine the ductwork airtightness. The airtightness of ductwork is useful knowledge when trying to improve energy conservation.
A thermographic inspection aka Infrared Scan consists of either an interior or exterior survey. The energy auditor decides which method would give the best results under certain weather conditions. Interior scans are more common, because warm air escaping from a building does not always move through the walls in a straight line. Heat loss detected in one area of the outside wall might originate at some other location on the inside of the wall. Also, it is harder to detect temperature differences on the outside surface of the building during windy weather. Because of this difficulty, interior surveys are generally more accurate because they benefit from reduced air movement.
Thermographic scans are also commonly used with a blower door test running. The blower door helps exaggerate air leaking through defects in the building shell. Such air leaks appear as black streaks in the infrared camera’s viewfinder.
Thermography uses specially designed infrared video or still cameras to make images (called thermograms) that show surface heat variations. This technology has a number of applications. Thermograms of electrical systems can detect abnormally hot electrical connections or components. Thermograms of mechanical systems can detect the heat created by excessive friction. Energy auditors use thermography as a tool to help detect heat losses and air leakage in building envelopes.
Infrared scanning allows energy auditors to check the effectiveness of insulation in a building’s construction. The resulting thermograms help auditors determine whether a building needs insulation and where in the building it should go. Because wet insulation conducts heat faster than dry insulation, thermographic scans of roofs can often detect roof leaks.
In addition to using thermography during an energy assessment, you should have a scan done before purchasing a house; even new houses can have defects in their thermal envelopes.
Why A HERS Score?
If you consider purchasing or building a new home, consider a HERS Certificate. This is valuable information for any homeowner and a score of 70 or lower on the scale indicates a home that has been built or remodeled with optimum energy saving features. The HERS Index measures a home’s energy efficiency and there are a lot of great reasons to have a HERS rating performed on your home.
The short video on the right explains how it works!
Whether you are purchasing a new or existing home, BPTC has the experience and know-how to assist you in finding potential weaknesses in terms of energy consumption and mechanical equipment efficiencies of any size residential building. We can pinpoint shortcomings and recommend upgrades to transform your building into a healthy and comfortable home.