FAQs on Home Sealing

What is Home Sealing?

Home Sealing is a process recommended by the EPA ENERGY STAR program to help increase the comfort and energy efficiency of your home by improving the envelope. The basic steps to Home Sealing include:

• Sealing air leaks to stop drafts and get full performance from insulation,
• Add insulation to stay comfortable during periods of high and low temperatures, and
• Choose ENERGY STAR qualified windows when replacing old windows.

EPA estimates that air sealing combined with additional insulation can make your home more comfortable and cut heating and cooling bills by up to 20%.

What is a home envelope?

The exterior of your home is also called the "envelope" or shell. The insulation, outer walls, ceiling, doors, windows, and floors all work together to control airflow in and out of the structure, repel moisture, and prevent heat from being lost or gained inside your home. A highperformance envelope helps maintain a consistent temperature even under extremely hot or cold conditions. The goal of Home Sealing is to improve the home envelope to make homes more comfortable and energy efficient.

What is air sealing and why is it important?

Air sealing is simply closing holes, cracks, and gaps where air can pass into or out of your home. On hot and cold days, you pay good money to run an air conditioner or a furnace/boiler to maintain your home at a comfortable temperature. A house that leaks air costs more to heat or cool because your system must work longer to "condition" the air. In addition, if you happen to sit next to one of those leaks, you are uncomfortable because the room feels hotter or colder. Sealing those air leaks will help you maintain your home at a comfortable temperature all year long and help lower energy bills.

Where are the biggest holes (air leaks) located?

The biggest holes are most often found hidden in the attic and the basement. However, there are many small holes located where pipes, wires, outlets, or ducts go through walls. There are also many small gaps or cracks around windows and doors that feel drafty, especially when the weather is cold outside. If you could add up all the air leaks in a home, they often can equal a hole the size of an open window - and can lead to a higher energy bill!

What materials should I use to seal these holes?

Caulk, spray foam, and weather stripping are the most common materials used for sealing these air sealing. A good rule of thumb is to use caulk on gaps and cracks that are up to 1/4 inch big. Caulk is great to use around window and door frames to reduce those uncomfortable drafts. Spray foam products can be used to fill holes that are 1/4 inch to about 3 inches in size. Be careful not to use foam around chimneys and flues that can get very hot. Holes that are larger than 3 inches should be covered with plywood, drywall, or rigid foam board and sealed shut. Weather stripping should be used around loose windows or to close gaps around doors. On the bottom of the door consider using a door sweep or threshold that seals.

What is the best caulk to use for sealing air leaks?

Be sure to use a long lasting, flexible caulk so you won’t have to go back redo the job in just few years. A high quality, latex-based caulk such as DAP® Dynaflex 230® Elastomeric Sealant, is perfect for sealing smaller gaps, cracks and holes. Its permanently flexible formula can accommodate up to 50 percent total joint movement without cracking or losing adhesion, making it perfect for regions that experience temperature fluctuations. Plus it is easy to apply, cleans up with soap and water, and comes with a 50-year durability guarantee.

Why is insulation important?

Insulation is designed to resist heat flow -- that is, if it is hot outside, insulation greatly reduces the amount of heat you can feel inside a house. Or, if it is cold outside, insulation helps keep the heat inside the house. Without insulation, the walls of your house would be very hot to the touch during the summer and your air conditioner must work harder to keep you cool. In the winter, a lack of insulation makes walls very cold to the touch and the furnace must work harder to keep you warm. Insulation works best when air is not moving through or around it. Therefore, it is very important that air leaks be sealed to ensure that you get the full performance out of any insulation that is installed. To get the biggest savings, the easiest place to add insulation is in the attic. When adding insulation to your house it is important to first evaluate how much and what type of insulation you currently have in you attic. For more comprehensive information, review the Department of Energy's online Insulation Guide at: http://www.ornl.gov/sci/roofs+walls/insulation/ins_01.html

Can I over-seal my house? (Make it too tight?)

While it is possible to seal a house too tightly, it is unlikely to happen in most older homes because they are generally quite leaky compared to newer homes that have been tested and sealed. A certain amount of fresh air is needed for good indoor air quality and there are specifications that set the minimum amount of fresh air needed for a house. If you are concerned about how tight your home is, you can hire an energy specialist who can perform leakage tests using diagnostic tools, and make sure all combustion (gas or oil burning) appliances are operating properly. If a home is too tight, fresh air ventilation can be added.

Is Home Sealing something I can do myself?

Yes! There are air sealing and insulation activities you can do yourself and it is worth doing. A handy homeowner can seal up holes, weather strip doors, caulk pipes and wires, and often insulate attic floors, basements, and crawl space walls. Remember, it's important to always air seal before adding insulation. ENERGY STAR has a written a Do-It-Yourself Guide to help with the process of Home Sealing which you can find here: A Do-It-Yourself Guide to Energy Star® Home Sealing. You can also find it at: http://www.energystar.gov/homesealing

Can I hire someone to help me do Home Sealing?

Yes, but sometimes they are hard to find. You can hire an energy specialist who uses special tools, like a blower door, to find hidden leaks and are experienced at sealing and adding insulation. The blower door can also test how tight your home is after sealing. A Home Energy Rater or other energy consultant can perform a blower-door test and develop a plan for the most cost-effective measures to improve your home. Also, blown-in and sprayed insulation are usually best left to professional installers who have all the equipment. If you hire a contractor, shop around and get several written bids. Remember that a quality installation is more important than low cost. At the end of a job, contractors that install insulation are required by the Federal Trade Commission to provide you with a signed receipt that shows the R-value of the insulation they added. Visit the ENERGY STAR web site to find out more: http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_contractors