Air Leak Inspections and Home Energy Audits

A home energy audit is the first step to assess how much energy your home consumes, and to evaluate what measures you can take to make your home more energy-efficient. An audit will show you problems that may, when corrected, save you significant amounts of money over time. During the audit, we can pinpoint where your house is losing energy. Audits also determine the efficiency of your home's heating and cooling systems. An audit may also show you ways to conserve hot water.

We use a variety of techniques and equipment to determine the energy efficiency of a structure. Thorough audits often use equipment such as blower doors, which measure the extent of leaks in the building envelope, as well as infrared cameras, which reveal hard-to-detect areas of air infiltration and missing insulation.

1) Locating Air Leaks

First, we make a list of obvious air leaks (drafts). The potential energy savings draft reduction may range from 5% to 30% per year, and the home is generally much more comfortable afterwards. We check for indoor air leaks such as gaps along the baseboard or edge of the flooring, and at junctures of the walls and ceiling. We check to see if air can flow through electrical outlets, switch plates, window frames, baseboards, weather-stripping around doors, fireplace dampers, attic hatches, and wall- or window-mounted air conditioners. We look for gaps around pipes and wires, electrical outlets, foundation seals, and mail slots. We check to see if the caulking and weatherstripping are applied properly (no gaps or cracks), and are in good condition.

We inspect windows and doors for air leaks and rattle them, since movement means possible air leaks. If we can see daylight around door and window frames, then the door or window leaks. You can usually seal these leaks by caulking or weather stripping them. We check the storm windows to see if they fit and are not broken. You may also wish to consider replacing your old windows and doors with newer, high-performance ones. If new factory-made doors or windows are too costly, you can install low-cost plastic sheets over the windows.

If we are having difficulty locating leaks, we may want to conduct a basic building pressurization test. First, we close all exterior doors, windows, and fireplace flues. Turn off all combustion appliances such as gas burning furnaces and water heaters. We then turn on all exhaust fans (generally located in the kitchen and bathrooms) or use a large window fan to suck the air out of the rooms. This increases infiltration through cracks and leaks, making them easier to detect. We can use incense sticks to locate these leaks. Moving air causes the smoke to waver, and one will feel a draft.

On the outside of your house, we inspect all areas where two different building materials meet. For example: we inspect all exterior corners; where siding and chimneys meet; and areas where the foundation and the bottom of exterior brick or siding meet. You should plug and caulk holes or penetrations for faucets, pipes, electric outlets, and wiring. Look for cracks and holes in the mortar, foundation, and siding, and seal them with the appropriate material. We check the exterior caulking around doors and windows, and see whether exterior storm doors and primary doors seal tightly.

2) Insulation

Heat loss through the ceiling and walls in your home could be very large if the insulation levels are less than the recommended minimum. We check to see if the level of the attic and wall insulation of your home is at least at the minimum recommended amount. When your house was built, the insulation recommended at that time was installed. Given today's energy prices, and that future prices probably will be higher, the level might be inadequate, especially if you have an older home. In 1997, the U.S. Department of Energy updated its recommended insulation R-Values.

If the attic hatch is located above a conditioned space, we check to see if it is at least as heavily insulated as the attic, is weather-stripped, and closes tightly. In the attic, to determine whether openings for items such as pipes, ductwork, and chimneys are sealed. Any gaps should be sealed with an expanding foam caulk or some other permanent sealant. If you have recessed light fixtures, determine if they are IC rated fixtures. It is strongly recommended that only air tight-IC rated fixtures be used. Other types allow large amounts of your heating dollar to escape into the attic. If you do not wish to purchase new IC rated fixtures, be certain to allow a three-inch space around any recessed lights. This will prevent the recessed light from overheating.

While we are inspecting the attic, we check to see if there is a vapor barrier (retarder) under the attic insulation. The vapor barrier might be tar paper, kraft paper attached to fiberglass batts, or a plastic sheet. If there does not appear to be a vapor barrier, you might consider painting the interior ceilings with vapor barrier paint. This reduces the amount of water vapor that can pass through the ceiling. Large amounts of moisture can reduce the effectiveness of insulation and promote structural damage. Make sure that the attic vents are not blocked by insulation. You also should seal any electrical boxes in the ceiling with flexible caulk (from the living room side or attic side) and cover the entire attic floor with at least the recommended amount of insulation.

Checking a wall's insulation level.  We select an exterior wall and turn off the circuit breaker or unscrew the fuse for any outlets in the wall. We remove the cover plate from one of the outlets and gently probe into the wall with a thin, long stick or screwdriver. If we encounter a slight resistance, we have some insulation there. We can also make a small hole in a closet, behind a couch, or in some other unobtrusive place to see what, if anything, the wall cavity is filled with. Ideally, the wall cavity should be totally filled with some form of insulation material. Unfortunately, this method cannot tell you if the entire wall is insulated, or if the insulation has settled. Only a thermographic inspection (discussed below) can do this.

3) Heating/Cooling Equipment

We recommend inspecting heating and cooling equipment annually, or as recommended by the manufacturer. If you have a forced air furnace, check your filters and replace them as needed. Generally they should be changed about once every month or two, especially during periods of high usage. If the unit is more than 15 years old, you should consider replacing it with one of the newer, energy-efficient units. This would go far to reduce your energy consumption, especially if the existing equipment is in poor condition. Check your ductwork for dirt streaks, especially near seams. These indicate air leaks, and they should be sealed with a duct mastic. Insulate any ducts or pipes that travel through unheated spaces. An insulation R-Value of 6 is the recommended minimum.

4) Lighting

Energy for lighting accounts for about 10% of your electric bill. We examine the wattage size of the light bulbs in your house. You may have 100 watt (or larger) bulbs where 60 or 75 watts would do. You should also consider compact fluorescent lamps for areas where lights are on for hours at a time. Your electric utility may offer rebates or other incentives for purchasing energy-efficient lamps.

Professional Energy Audits

All professional energy audits should, at a minimum, include a "walk-through" similar to the one above and a blower door test (discussed below). Most will also include a thermographic scan (also discussed below). Professional audits generally go into great detail. We do a room-by-room examination of the residence, as well as a thorough examination of past utility bills.

Before we visit your house, make a list of any existing problems such as condensation and uncomfortable or drafty rooms. Have copies or a summary of the home's yearly energy bills. (Your utility can get these for you.) We use this information to establish what to look for during the audit.  We first examine the outside of the home to determine the size of the house and its features (i.e., wall area, number and size of windows).

Thermographic Inspection

We use Infrared Thermography to scan and detect thermal defects, water and air leakage in building envelopes. Thermography measures surface temperatures by using infrared video and still cameras. These tools see light that is in the heat spectrum. Images on the video or film record the temperature variations of the building components,  each having a unique temperature signature.  The resulting images help us determine whether repairs are needed. They also serve as a quality control tool, to ensure that insulation, reinforcing bars and other building components have been installed correctly.

A thermographic inspection is either an interior or exterior survey. We decide 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, interior surveys are generally more accurate, as they benefit from reduced air movement. Thermographic scans are also commonly used.

Another use of Infrared Thermography is to locate electrical hotspots, defects in electrical wiring, leaking water supply and drain lines.

Insurance companies are now mandating the use of Infrared Thermography to support water damage insurance claims.