Energy Audits/Energy Assessments offered by Green Planet Building.Green Planet Building offers in-home energy audits that do much more for your family than just save you money. Our energy assessments help protect your family against harmful in-door air pollutants, threats from off-gassing and chemical fumes known as VOC's (volatile organic compounds). What is an energy audit?An energy audit is an evaluation of energy consumption, as in a home or a business, to determine ways in which energy can be conserved. A home energy audit and/or assessment is the first step taken to assess a structure's energy consumption. At this point we can evaluate the steps to making the home/building more energy efficient. The energy assessment can bring to light the issues your home is having with efficiency, saving a significant amount of money over time. What do we learn from an energy assessment/audit?An energy audit reveals where your home is losing energy and how to make changes to correct the issue. At Green Planet Building our auditors are BPI certified and they carry the necessary equipment to determine the energy efficiency of a structure. For example Blower Doors-which measure the extent of leaks in the building envelope (structure) and Infrared Cameras-which reveal hard to detect areas of air infiltration and missing insulation. Start saving today with a BPI Certified Energy Audit/Assessment for your residential or commercial application SaveNow! Blower Door TestsProfessional energy auditors use blower door tests to help determine a home's air tightness. These are some reasons for establishing the proper building tightness: Reducing energy consumption due to air leakage. Avoiding moisture condensation problems. Avoiding uncomfortable drafts caused by cold air leaking in from the outdoors Making sure that the home's air quality is not too contaminated by indoor air pollution. How They WorkA 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.  There are two types of blower doors: calibrated and uncalibrated. It is important that auditors use a calibrated door. This type of blower door has several gauges that measure the amount of air pulled out of the house by the fan. Uncalibrated blower doors can only locate leaks in homes. They provide no method for determining the overall tightness of a building. The calibrated blower door's data allow the auditor to quantify the amount of air leakage and the effectiveness of any air-sealing job. Preparing for a Blower Door TestTake the following steps to prepare your home for a blower door test: Close windows and open interior doors Turn down the thermostats on heaters and water heaters Cover ashes in wood stoves and fireplaces with damp newspapers Shut fireplace dampers, fireplace doors, and wood stove air intakes. Thermographic InspectionsEnergy auditors may use thermography—or infrared scanning—to detect thermal defects and air leakage in building envelopes. How They WorkThermography 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's skin, ranging from white for warm regions to black for cooler areas. The resulting images help the auditor determine whether insulation is needed. They also serve as a quality control tool, to ensure that insulation has been installed correctly. A thermographic inspection is 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. You may wish to include a clause in the contract requiring a thermographic scan of the house. A thermographic scan performed by a certified technician is usually accurate enough to use as documentation in court proceedings. The energy auditor may use one of several types of infrared sensing devices in an on-site inspection. A spot radiometer (also called a point radiometer) is the simplest. It measures radiation one spot at a time, with a simple meter reading showing the temperature of a given spot. The auditor pans the area with the device and notes the differences in temperature. A thermal line scanner shows radiant temperature viewed along a line. The thermogram shows the line scan superimposed over a picture of the panned area. This process shows temperature variations along the line. The most accurate thermographic inspection device is a thermal imaging camera, which produces a 2-dimensional thermal picture of an area showing heat leakage. Spot radiometers and thermal line scanners do not provide the necessary detail for a complete home energy assessment. Infrared film used in a conventional camera is not sensitive enough to detect heat loss. Preparing for a Thermographic InspectionTo prepare for an interior thermal scan, the homeowner should take steps to ensure an accurate result. This may include moving furniture away from exterior walls and removing drapes. The most accurate thermographic images usually occur when there is a large temperature difference (at least 20°F [14°C]) between inside and outside air temperatures. In northern states, thermographic scans are generally done in the winter. In southern states, however, scans are usually conducted during warm weather with the air conditioner on. Air SealingAir leakage, or infiltration, occurs when outside air enters a house uncontrollably through cracks and openings. Properly air sealing such cracks and openings in your home can significantly reduce heating and cooling costs, improve building durability, and create a healthier indoor environment. It is unwise to rely on air leakage for ventilation because it can't be controlled. During cold or windy weather, too much air may enter the house. When it's warmer and less windy, not enough air may enter. Air infiltration also can contribute to problems with moisture control. Moldy and dusty air can enter a leaky house through such areas as attics or foundations. This air in the house could cause health problems. The recommended strategy in both new and old homes is to reduce air leakage as much as possible and to provide controlled ventilation as needed. For more information, see the following resources: Air Sealing an Existing Home Air Sealing for New Home Construction Note that air sealing alone can't replace the need for proper insulation throughout your home, which is needed to reduce heat flow. Insulation and Air SealingYou can reduce your home's heating and cooling costs through proper insulation and air sealing techniques. These techniques will also make your home more comfortable. Any air sealing efforts will complement your insulation efforts, and vice versa. Proper moisture control and ventilation strategies will improve the effectiveness of air sealing and insulation, and vice versa. Therefore, a home's energy efficiency depends on a balance between all of these elements:
Moisture ControlProperly controlling moisture in your home will improve the effectiveness of your air sealing and insulation efforts, and vice versa. Thus, moisture control contributes to a home's overall energy efficiency. The best strategy for controlling moisture in your home depends on your climate and how your home is constructed. Before deciding on a moisture control strategy for your home, you may first want to understand how moisture moves through a home. Moisture control strategies typically include the following areas of a home:
VentilationWhen creating an energy-efficient, airtight home through air sealing techniques, it's very important to consider ventilation. Unless properly ventilated, an airtight home can seal in indoor air pollutants. Ventilation also helps control moisture—another important consideration for a healthy, energy-efficient home. Purpose of VentilationYour home needs ventilation—the exchange of indoor air with outdoor air—to reduce indoor pollutants, moisture, and odors. Contaminants such as formaldehyde, volatile organic compounds, and radon can accumulate in poorly ventilated homes, causing health problems. Excess moisture in a home can generate high humidity levels. High humidity levels can lead to mold growth and structural damage to your home. To ensure adequate ventilation, the American Society of Heating, Refrigerating and Air- Conditioning Engineers (ASHRAE) says that a home's living area should be ventilated at a rate of 0.35 air changes per hour or 15 cubic feet per person per minute, whichever is greater. Ventilation StrategiesThere are three basic ventilation strategies:Natural ventilation: Uncontrolled air movement into a home through cracks, small holes, and vents, such as windows and doors. Not recommended for tightly sealed homes.Whole-house ventilation: Controlled air movement using one or more fans and duct systems. Spot ventilation: Controlled air movement using localized exhaust fans to quickly remove pollutants and moisture at their source. This is typically used in conjunction with one of the other strategies. Air Sealing an Existing HomeAir sealing is one of the most significant energy efficiency improvements you can make to your home. Air sealing will not just reduce energy costs; it will also improve your home's comfort and durability. Before air sealing, you should first do the following: Detect air leaks Assess your ventilation needs for indoor air quality. You can then apply air sealing techniques and materials as needed, including caulk and weather-stripping. For other air sealing techniques, see the Learn More resources on the right side of this page (or below if you've printed it out). If you're completely remodeling your home, which will include some construction, also review some of the techniques used for air sealing in new home construction. Air Sealing for New Home ConstructionAir sealing is an important factor when constructing an energy-efficient home. These are some air sealing techniques and materials:
How Moisture Moves through a Home To help understand the principles of moisture control, you need to understand the basics of how moisture can move through your home. Moisture or water vapor moves in and out of a home in three ways:
The other two driving forces—diffusion through materials and heat transfer—are much slower processes. Most common building materials slow moisture diffusion to a large degree, although they never stop it completely. Insulation also helps reduce heat transfer or flow. The laws of physics govern how moist air reacts within various temperature conditions. The study of moist air properties is technically referred to as "psychrometrics." A psychrometric chart is used by professionals to determine at what temperature and moisture concentration water vapor begins to condense. This is called the "dew point." By understanding how to find the dew point, you will better understand how to avoid moisture problems in your house. Relative humidity (RH) refers to the amount of moisture contained in a quantity of air compared to the maximum amount of moisture the air could hold at the same temperature. As air warms, its ability to hold water vapor increases; this capacity decreases as air cools. For example, according to the psychometric chart, air at 68ºF (20ºC) with 0.216 ounces of water (H2O) per pound of air (14.8g H2O/kg air) has a 100% RH. The same air at 59ºF (15ºC) reaches 100% RH with only 0.156 ounces of water per pound of air (10.7g H2O/kg air). The colder air holds about 28% of the moisture that the warmer air does. The moisture that the air can no longer hold condenses on the first cold surface it encounters (the dew point.) If this surface is within an exterior wall cavity, wet insulation and framing will be the result. In addition to air movement, you also can control temperature and moisture content. Since insulation reduces heat transfer or flow, it also moderates the effect of temperature across the building envelope cavity. In most U.S. climates, properly installed vapor diffusion retarders can be used to reduce the amount of moisture transfer. Except in deliberately ventilated spaces, such as attics, insulation and vapor diffusion retarders work together to reduce the opportunity for condensation in a house's ceilings, walls, and floors. To effectively control moisture in your home, you need to first consider your climate when exploring your moisture control options. Vapor Barriers or Vapor Diffusion RetardersIn most U.S. climates, vapor barriers or vapor diffusion retarders should be considered as part of a moisture control strategy for a home. How They WorkA vapor barrier or vapor diffusion retarder (VDR) is a material that reduces the rate at which water vapor can move through a material. The older term "vapor barrier" is still used even though it may inaccurately imply that the material stops all of the moisture transfer. Since everything allows some water vapor to diffuse through it to some degree, the term "vapor diffusion retarder" is more accurate. The ability of a material to retard the diffusion of water vapor is measured by units known as "perms" or permeability. A perm at 73.4°F (23°C) is a measure of the number of grains of water vapor passing through a square foot of material per hour at a differential vapor pressure equal to one inch of mercury (1" W.C.) Any material with a perm rating of less than 1.0 is considered a vapor retarder. Vapor diffusion retarders can help control moisture in these areas:
 Types of Vapor Diffusion RetardersVapor diffusion retarders are typically available as membranes or coatings. Membranes are generally thin, flexible materials, but also include thicker sheet materials sometimes called "structural" vapor diffusion retarders. Materials such as rigid foam insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor diffusion retarders are usually mechanically fastened and sealed at the joints. Thinner membrane types come in rolls or as integral parts of building materials. A common example of this is aluminum- or paper-faced fiberglass roll insulation. Foil- backed wallboard is another type commonly used. Polyethylene, a plastic sheet material, can be used as a vapor diffusion retarder for above-grade walls and ceilings (only) in very cold climates (in locations with 8,000 Heating Degree Days or higher). Most paint-like coatings also retard vapor diffusion. While it was once believed that only coatings with low perm ratings constituted the only effective vapor diffusion retarders, it is now believed that any paint or coating is effective at restricting most water vapor diffusion in milder climates. Installing Vapor Diffusion Retarders for New ConstructionIn climates with less than 4,000 Heating Degree Days, materials like painted gypsum wallboard and plaster wall coatings impede moisture diffusion to acceptable levels. Usually, no further vapor diffusion retarder is needed. In more extreme climates, vapor diffusion retarders are advisable for new construction. They perform best when installed closest to the warm side of a structural assembly; in cold climates, this is towards the interior of the building. In hot/wet climates, this is towards the exterior of the building. Reasonable rules-of-thumb to follow when placing vapor retarders include the following: In climates with 2,200 or more Heating Degree Days, locate the vapor diffusion retarder on the warm side of the exterior structural assembly. If possible, locate it on the inside of the assembly using the "one-third, two-thirds rule": the vapor diffusion retarder has one- third of the cavity insulation to its warm side, two-thirds to the cold side. This protects the retarder from physical damage through errant construction or remodeling activities. In climates with fewer than 2,200 Heating Degree Days (cooling-dominated climates) and where the building is near, but not quite in, the 2,200 Heating Degree Days zone (a.k.a. fringe zone), place the vapor diffusion retarder in the same location as climates farther north. Farther south (about 1,900 Heating Degree Days) it is unimportant where the vapor diffusion retarder goes. For climates even farther south and generally hotter and more humid, some professionals recommend omitting the vapor diffusion retarder completely. This is due to the winter heating loads and summer cooling loads being roughly equal. Any location ends up having the vapor diffusion retarder on the wrong side of the structure during part of the year. However, other building science research indicates that it should be applied directly under the exterior finish and is sometimes itself the exterior finish. A combination air barrier/vapor diffusion retarder may be a better choice for this situation. Knowledgeable builders typically use vapor diffusion retarders with ratings of 0.1 or less. However, if you carefully seal the warm-side vapor diffusion retarder and interior finish, you can also safely install a low-permeable material, such as rigid foam board insulation (a perm rating as high as 1.4), on the cold side of walls. A good rule-of-thumb: to prevent trapping any moisture in a cavity, the cold-side material's perm rating should be at least five times greater than the value of the warm-side. Use a vapor diffusion retarder with a perm value of less than 0.50 if you also have a high water table. When installing a vapor diffusion retarder, it should be continuous and as close to perfect as possible. This is especially important in very cold climates and in hot and humid climates. Be sure to completely seal any tears, openings, or punctures that may occur during construction. Cover all appropriate surfaces; otherwise, you risk moist air condensing within the cavity, which would lead to dampened insulation. The thermal resistance of wet insulation is dramatically decreased, and prolonged wet conditions will induce mold and wood rot. Installing Vapor Diffusion Retarders in Existing HomesExcept for extensive remodeling projects, it's difficult to add materials like sheet plastic as a vapor diffusion retarder to an existing home. However, many existing homes don't really need a more effective vapor diffusion retarder than the numerous layers of paint usually on their walls and ceilings. These multiple layers are quite effective as a vapor diffusion retarder in all but the most extreme northern climates. "Vapor barrier" paints are also an effective option for colder climates. If the perm rating of the paint is not indicated on the label, find the paint formula. The paint formula usually indicates the percent of pigment. To be a good vapor diffusion retarder, it should consist of a relatively high percent of solids and thickness in application. Glossy paints are generally more effective vapor diffusion retarders than flat paints, and acrylic paints are generally better than latex paints. When in doubt, apply more coats of paint. It's best to use paint labeled as a vapor diffusion retarder and follow the directions for applying it. |
