Insulate and air seal your home

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Many of us live in homes built before 1970. If you live in one of these older homes, the insulation in your walls may not meet modern energy efficiency standards. And almost every home in Melrose could use air sealing to reduce gaps that allow in cold air. For perspective, some older homes have as much as five times the air leakage of a new construction home today. That is a lot of cold air seeping into your home making it uncomfortable and expensive to heat.

Start with installing all of the MassSave-subsidized insulation and air sealing available. The first stop for upgrading your insulation and air sealing is Mass Save, the state sponsored energy efficiency program, which provides financial incentives that cover 100% of air sealing costs and 75% of the cost of insulation upgrades recommended through a no-cost home energy assessment.  There is also a 0% loan program for up to $25,000 for financing HVAC and energy efficiency measures.   

If you have already had a Mass Save home energy assessment but it was more than two years ago, it is worth having one again, as the incentives and the work covered in the program have gotten better over time.  If your assessment is within the last two years you can still receive the incentive; check with the company who did that assessment to see if you qualify.

Keep on top of drafts, cold spots and air leakage.   Small air leaks and gaps in insulation can often be easily addressed by homeowners or local handymen with caulk, expanding foam and weatherstripping, and can have a big impact on energy usage. Even well-insulated homes, including those that have had MassSave sponsored upgrades, can have gaps and leaks due to later work by contractors, deterioration of caulking, insulation settling or getting wet, and other routine problems that can develop over time. 

Homeowners often think of doors and windows, but more than half of the air leakage in homes is through floors, walls and ceilings. Duct work is another major source of leaks where ducts pass through unconditioned spaces. Attic leaks are the most important to address due to the stack effect – as rising warm air leaves the house through leaks in the attic, it is replaced by cold air on the lower floors. Today’s insulation contractors usually do a good job air sealing when they insulate an attic, but that was not always the case in the past.



Want to go deeper?   There are many more energy efficient improvements you can make beyond the standard Mass Save approved insulation and air-sealing, especially if you are making home improvements such as re-siding your home or having a renovation or addition done. Ask prospective contractors if they are familiar with measures that go beyond the current building code, such as continuous exterior insulation.   MassSave has additional incentives for major renovations and additions, as well as 0% loans for greater energy efficiency measures.

  1. Don't wait to sign up for a no-cost home energy assessment. Without this assessment, you can't get the insulation and air sealing incentive. 
  2. Following the home energy assessment, take the recommended action and take advantage of the MassSave subsidized air sealing and insulation. 
  3. Know your home’s insulation and air sealing, and make it a yearly practice to inspect and repair weatherstripping and air gaps. 
  4. Have a blower door test done to determine how tight your home is, and to help locate air leaks.

If you are planning home improvements or an addition or major renovation, look for opportunities to install enhanced insulation and air sealing.   

Changes in the air tightness of a home can impact combustion appliances such as furnaces and hot water heaters, so make sure you have these systems professionally checked if there are major changes to your home’s air tightness.  If your home becomes really tight (equivalent to new construction or tighter) you may even need to provide additional ventilation – if so, congratulations!  A blower door test can be used to assess the home’s air tightness and whether there is sufficient ventilation.

Want to know more about how insulation and air sealing work in your home? Understanding how your home’s insulation and air sealing work can help you save energy and money.  The Department of Energy has some great information about insulation and air sealing on its weatherization page.

Insulation is rated by “R-value”, a measure of the material’s resistance to conductive heat flow. Different insulation materials have different R-values; for example a four inch thick fiberglass batt may provide R-15, while the same thickness of a blown-in foam insulation might be R-28 depending on the type of foam used. In Massachusetts the Department of Energy recommends upgrading insulation levels to R-60 in the attic, R-30 under floors over uninsulated spaces, and R-23 in walls (which usually requires adding continuous insulation to the exterior of the home under the siding – a great upgrade to make if you are residing your home!).

Air sealing addresses the drafts and air leaks caused by holes and gaps throughout the house, especially the attic and basement.  According to Mass Save, leaking air can often account for up to 30% of a home’s heating and cooling costs and can sometimes be the equivalent of having a window open to the outside all year round. Air sealing is also one of the most effective ways to improve home comfort by eliminating drafts and cold spots in the home. Common problem areas for air sealing are shown in the figure below and will be checked during a home energy assessment.

Need some guidance in doing your own home energy efficiency work? There is a lot that homeowners can do on their own to make their house more comfortable and energy efficient, in between or in addition to professional home energy assessments and upgrades.  EnergyStar has published a comprehensive DIY guide to air sealing and insulating; or see the following tips from  energy.gov/energysaver:

  • Caulk and weatherstrip doors and windows that leak air.
  • Caulk and seal air leaks where plumbing, ducting, or electrical wiring comes through walls, floors, ceilings, and soffits over cabinets.
  • Install foam gaskets behind outlet and switch plates on walls.
  • Inspect dirty spots on any visual insulation for air leaks and mold. Seal leaks with low-expansion spray foam made for this purpose and install house flashing if needed.
  • Look for dirty spots on your ceiling paint and carpet, which may indicate air leaks at interior wall/ceiling joints and wall/floor joists, and caulk them. (Spider webs can also be sign of air leaks)
  • Replace single-pane windows with more efficient double-pane low- emissivity windows. (You can also add storms to older windows, and have original windows serviced rather than replaced)
  • Use foam sealant on larger gaps around windows, baseboards, and other places where air may leak out.
  • Check your dryer vent to be sure it is not blocked. This will save energy and may prevent a fire.
  • Replace exterior door bottoms and thresholds with ones that have pliable sealing gaskets.
  • Keep the fireplace flue damper tightly closed when not in use.
  • Seal air leaks around fireplace chimneys, furnaces, and gas-fired water heater vents with fire-resistant materials such as sheet metal or sheetrock and furnace cement caulk.

Interested in actions beyond insulation and air sealing? There are a lot more ways to improve your home’s energy efficiency, including:

  1. Convert to an electric heat pump heating and cooling
  2. Convert to an electric heat pump water heater
  3. Change to electric induction cooking
  4. Carry out advanced air sealing through blower door directed air sealing
  5. Add heat recovery ventilation to improve air quality and preheat fresh air entering your home 
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