Your home consists of two primary systems that work together to provide comfort and shelter. Your home’s heating and cooling system maintains comfortable indoor temperatures. Your home’s envelope helps hold in comfortable indoor temperatures and provides shelter from exterior elements. The home envelope is the combination of materials that surround the interior space you live in including walls, floors, ceiling, roof, windows, and doors. The quality and integrity of your home’s envelope greatly affects the comfort and cost to operate your home. How can improving my home’s envelope save money and energy? The average family spends $1,900 a year on energy bills, nearly half of which goes to heating and cooling. These costs can be reduced by up to 20% by combining the right amount and type of insulation, using effective air sealing techniques, and installing windows that are appropriate for your climate. What are the benefits of an energy efficient envelope?
- Reduced drafts and even room temperatures (no cold or hot rooms).
- Reduced noise transmission into your home.
- Savings on heating and cooling bills.
- Moisture control in your home leading to longer life of your home’s building materials and reduced incidence of mold and mildew.
Why is insulation important? The proper type and level of insulation for your home provides a continuous thermal barrier minimizing heat flow through the walls, ceiling, and floor. The result is a more comfortable home and reduced heating and cooling costs. Installing insulation properly is as important as the type and level of insulation because gaps, voids, compressions, and moisture reduce the effectiveness of insulation and allow unconditioned air to enter your home. What are air and vapor barriers? Air barriers are any material used to prevent the movement of air through walls, ceilings, and floors. Vapor barriers keep moisture, which is often contained in air, from passing through and condensing in walls, floors, and ceilings. Air and vapor barriers must be installed in a manner appropriate to your climate region to work correctly. This is always toward the warmer side of the wall or ceiling. Remember: Check your local code to see what is appropriate for your climate region. Why is air sealing important? Ceiling, wall, and floor systems with insulation generally provide barriers to outside air coming into the home. However, small gaps, cracks, and spaces that are not closed around penetrations will allow uncontrolled outside air from entering temperature-controlled spaces. You will feel air infiltration from larger gaps as drafts that make a room uncomfortable. To detect smaller cracks that affect the energy efficiency of your home, you may need to hire a professional contractor who uses a blower door and other tools to determine the location of air leakage. Remember: It is always a good idea to check your hot water heater, furnace, gas stove and other combustion appliances as well as your carbon monoxide detectors to make sure they are in working order. What should I know about ventilation? Although air sealing is intended to prevent outside air from leaking into your house, a certain amount of controlled fresh air is important to keep the indoor air quality healthy. Proper ventilation provides fresh air and removes stuffy indoor air and excess moisture. Once your home is properly air sealed you should make sure that adequate ventilation is provided. To do this, you may need to hire a professional to conduct a blower door test. Ventilation to remove excess moisture and pollutants can be as simple as exhaust fans in the kitchen and bathrooms. More complex systems can cover the entire house and may include heat recovery, moisture control, and air filtering. Remember: Everyday activities such as cooking and bathing create moisture that needs to be expelled from the house to avoid mold and mildew. This will also help to keep the insulation dry so that it provides an effective thermal barrier from outside conditions. Should I install the insulation myself or hire a contractor? There are air sealing and insulation activities you can do yourself. A careful homeowner can often insulate attic floors, basements, new or open walls, and crawl space walls. Blown-in and sprayed-in insulation as well as adding insulation to a mobile home are best left to the professional installer. It’s important to remember, however, that insulation needs proper air-sealing to work well. And without the necessary training and equipment, you won’t know what your air-leakage is, nor if you have combustion safety problems. If you do choose to tackle this effort yourself, the Energy Star Home Sealing Guide offers specific recommendations on ways you can tighten your home envelope. You can learn more on the Energy Star Web site. Why should I hire a professional? Energy consultants use tools such as blower-doors to diagnose your house and develop a plan for the most cost-effective measures to take in your particular situation. What should I know if I’m going to hire a contractor? Shop around and get several written bids for the same work (same R-value), and remember that good quality is as important as low cost. Get a receipt. The contractor is required by the Federal Trade Commission to provide you with a signed receipt that shows the R-value. Consider having the installation checked by a third-party, energy consultant or home inspector to make sure it has been installed correctly. Source: U.S. DOE/EPA Energy Star Program