Insulate & Weatherize to the Max

Impact

Cost

Many Homes Should Have More Or Better Insulation

Most households in Acton have some insulation, but many homes would benefit from more or better insulation in order to save energy (and money on their heating and cooling bill) — and to prepare their homes/buildings for installation of efficient, electric heat pump systems for heating and cooling. If you live in an older home, the insulation in your walls may not meet modern energy efficiency standards, and nearly every home in Acton could use “air sealing” to reduce gaps that allow in cold air. For example, an older home may have 250% greater air infiltration than a newly constructed one; that is a lot of cold air entering a home and warm air leaving it, which makes heating it inefficient and expensive.

On average in Acton, insulating and air sealing a home (sometimes called weatherization) can be expected to reduce annual emissions by 1.5 tons, as explained under the “Deep Dive” section. Only a few Actions (including EVs and the transition to heat pump technology) can reduce emissions by this much.

To learn more about weatherization, the Department of Energy has very informative webpages regarding air-sealing your home and everything you want to know about insulation including what kinds there are and where and how to insulate.

Find Out If Your Home Is Properly Insulated And Air Sealed

Schedule a no-cost Home Energy Assessment (or energy audit) through Mass Save. An Energy Specialist will conduct an inspection of your home and offer recommendations for improvement of its energy efficiency, and can also recommend vetted contractors to perform the work.

Inspections may include the following: physical inspections and measurements of insulation type and thickness in walls, ceilings and attics; checking for gaps, damaged insulation, and settled fibers; blower door tests to evaluate air leaks; and sometimes thermal infrared imaging to identify areas of missing or insufficient insulation. During the assessment, the Energy Specialist may also install, at no cost to you, LED bulbs, smart power strips, programmable thermostats, perform air sealing, etc. Thermostats may be available at greatly reduced cost to renters and LED light bulbs are also sometimes available to electricity customers at reduced cost (note: these offers may change over time).

Take Advantage Of Money Saving Incentives

Mass Save, the energy efficiency and decarbonization program overseen by electric and gas utilities and sponsored by the Commonwealth of MA, offers a rebate that covers 75% to 100% of the cost of approved insulation upgrades, with no-cost air sealing, and a 0% loan program for financing energy efficiency and heating system updates. (The Energy Specialist can give you details during the assessment.) Be sure to follow up on the Mass Save audit to take advantage of these incentives and to make your home more comfortable and energy efficient.

Very ambitious and comprehensive actions are called for by the goal stated in the Climate Emergency Declaration (adopted by Acton Town Meeting in September 2020): to “bring net Town-wide carbon emissions to zero as quickly as possible, with a target date of 2030.” Achieving this goal will require most of the buildings in Acton to make all the feasible investments they can in order to reduce carbon emissions sufficiently. Homeowners, with support from the Town and State governments, will need to assess not only maximizing insulation and energy efficiency, but taking other actions as well such as: installing heat pumps, going 100% renewable for household electricity (via signing up for Acton Power Choice GREEN and/or installing on-site solar), switching to EVs for driving, and installing energy storage (battery) systems.

Maximizing insulation and weatherization is an easy and affordable way to start your emissions-reduction journey. This action provides the best carbon-reduction return on your investment.

If you’re considering switching to heat pump technology for heating and cooling (and/or hot water), upgrading your insulation and weatherization may be required first in order to qualify for the full financial incentives from Mass Save for the heat pumps. Upgrading your insulation and weatherization will also cut the heat pump installation cost by reducing the overall heating and cooling load which subsequently reduces the size of the heat pump required. For example, moving from a 4-ton to a 3-ton capacity system can mean a system installation cost reduction of $1,000–$3,000 not to mention the long term annual savings of not having to heat or cool a less insulated or weather proof home.

Steps to Take

Start with the Mass Save Online Home Energy Assessment. It just takes a few minutes to set up a customized energy profile, which lets you see how you’re currently using energy and based on your answers you will receive recommendations regarding how to save energy. If you are a renter, Eversource has information on how to lower energy use and also see the “Savings for Renters” Action here on EnergizeActon.org.
To prepare for your Home Energy Assessment (energy audit), you may want to consult a volunteer Acton Clean Energy Coach with this Coaching Request Form. You might also want to use the Cool Climate household carbon emissions calculator to provide you with a perspective on how your home’s energy use contributes to your overall carbon emissions, and to have some base numbers against which to compare estimates of emission reductions provided during your assessment.
Schedule an in-person Home Energy Assessment. To arrange for an in-person or virtual Home Energy Assessment you can call Mass Save (866-527-7283) or go to Mass Save Home Energy Assessments and choose a Home Performance Contractor (HPC) who will do the assessment. You can review the Mass Save list of all the HPCs that cover our area. (FYI, as of January 2026, the Town of Acton’s Sustainability Office was in the process of selecting and contracting with a single HPC who would be dedicated to serve Acton, so check with them to see if that has happened yet.) To sign up for the Mass Save Home Energy Assessment, you may have to have your electricity and natural gas account numbers ready, and if asked, say Energize Acton referred you.
If you are planning an addition or renovation project, look into Mass Save’s alternative program offering for that process. Note that as of July 1, 2024, sponsors of Mass Save have discontinued these incentives for homes that utilize equipment powered by natural gas, oil, and propane. New project registrations must meet the program’s new electrification requirements to qualify for these incentives.
During the assessment, be sure to tell your Energy Specialist that you want to learn about the ways to achieve the greatest carbon emissions reductions to support Acton’s net zero emissions goal. To that end, you can ask for information about heat pumps (for heating & cooling and hot water heating); rooftop solar energy (whether through purchase or a Power Purchase Agreement); and electric vehicle (EV) charging stations. Some HPCs may offer more of these options than others.
Following the Home Energy Assessment, select the insulation, air sealing, and other measures that you want and execute a contract (or contracts) with your chosen vendor(s). Take advantage of the Mass Save rebates for installing insulation and no-cost air sealing. If you use an HPC to do the assessment, that contractor can proceed to contract for the measures you select, or you may seek quotes from other contractors. Be sure to ask whether a contractor is eligible for you to receive Mass Save rebates for work performed. Have the final work examined by Mass Save inspectors, and if needed, by local building or electrical inspectors.
If you elect to proceed with only some energy-saving options at this time, make an explicit Home Energy Plan to schedule other options you’d like to pursue in the future (see our Action “Create a Zero Emissions Plan”). For heating systems: it is important to contact a heat pump installer now and develop a plan — in the event your existing furnace or boiler fails without warning — to move quickly on installation of pre-selected heat pump equipment. (see Heat & Cool: Heat Pumps Action). Please Create a Zero Emissions Plan to stop burning fossil fuels — as soon as you are ready to (or have to) replace existing fossil-fueled (gas, oil, or propane) equipment.
Let us know how it went! Please write a Testimonial below. .

Deep Dive

To Help “Bring Net Carbon Emissions To Zero As Quickly As Possible,” What Questions Should I Ask My Mass Save Contacts?

To look into your options within the Mass Save program, you may contact a volunteer Acton Energy Coach with this Coaching Request Form. When speaking with Mass Save, first ask your Energy Specialist and Mass Save contractors for quotes to maximize your insulation. Add the amounts (and types) of insulation that would be required for a new home or recommended for a “super-insulated” home (e.g., R-65 in an attic), which will usually be more than Mass Save suggests (e.g., R-50). Ask about insulating walls as well as attics, and whether there are insulation options for your home that are not offered through Mass Save; these might be insulation for flat roofs or cathedral ceilings, or in finished attic spaces. Ask how you could address those limitations (e.g., with a separate insulation contractor or during re-roofing).

If your in-person, no-cost Home Assessment does not include a “blower door” test or the use of a blower door for an “advanced” air sealing process, ask for suggestions for how to contract someone who can provide this approach. Such a test can confirm that your air sealing will really reduce your home’s air leakage as much as it should.

Make sure the final work is examined by Mass Save inspectors who will need to ensure the work meets program standards before final payment and incentives are released. You may also need to have inspections by local (municipal) building or electrical inspectors.

To support Acton’s net zero emissions goal, ask your Energy Specialist about rebates for additional energy efficiency measures beyond insulation and air-sealing, including opportunities to install climate-friendly heat pump systems for heating and cooling. See the Heat & Cool: Heat Pumps Action.

There are also technologies that the Mass Save Home Energy Assessment and rebates do not address, including on-site solar (roof or ground mount), and electric vehicles with home charging. Make sure to ask Mass Save and contractor personnel for suggestions in these areas, as well. Check out the relevant EnergizeActon.org Actions for detailed information on these and other measures that will get Acton closer to our zero emissions goal, such as Install Solar and Drive Electric.

How Important Are Insulation And Air Sealing For Meeting Acton’s Net Zero Emissions Goal?

“Insulation to the Max” is a very effective step in cutting carbon emissions at home, as shown in the following table. These data are estimates by MassEnergize and Energize Acton of the number of tons of CO₂ equivalents (MTCO₂e) the average Actonian could stop emitting each year from these six emissions-reducing Actions.

The Top 6 Actions for Cutting Household Carbon Emissions

Action	Average Tons /Action/year
1. Switch to Green Heating & Cooling (Air Source Heat Pump)	3.2
2. Drive Electric (1 car)	2.6
Also Opt up to APC GREEN for charging use by 1 EV	1.5
3. Install On-site Solar	(2.5)
4. Insulate & Weatherize to the Max	1.5
5. Opt Up to APC GREEN (at average household usage)	1.5
Also Opt up to APC GREEN for heat pump use	2.0
6. Eat More Plant-Based Meals	0.6

Sources: MassEnergize Carbon Calculator Methodology, Energize Acton conversions to metric tons based on 2,204.62 pounds/metric ton.

Although “max” insulation can yield estimated emissions savings of 1.5 tons/year, even bigger reductions can be realized with heat pumps, EVs, and on-site solar. Reductions will vary from one household to the next, but if a household does all six things in this table, the carbon savings would be approximately 13 tons of carbon annually. This is roughly 74% of the average 17.5 tons of emissions per household (as counted in the 2019 Acton Greenhouse Gas Inventory) from home energy use and passenger cars in Acton. (Note: on-site solar was omitted from the 13-ton total because most of solar’s potential emissions reduction is achieved in this scenario by APC GREEN.)

Here are additional measures Energize Acton recommends beyond basic insulation and air sealing:

Convert to an electric heat pump for heating and cooling (see Heat & Cool: Heat Pumps)
Convert to an electric heat pump water heater
Switch to (Electric) Induction Cooking
Replace upper-level recessed light fixtures with insulated LED ones
Install a draft stopper for your chimney
Install storm windows or air seal your windows with caulk. You can consider completely replacing your windows, although the energy savings may not justify the expense of new windows.
If you need to improve air quality and preheat fresh air entering your home, especially after thorough air sealing, consider Energy Recovery Ventilators (ERVs).

Many of these improvements are better done in conjunction with others. It may be a good idea to speak with multiple contractors if you are interested in one or more of the above.

What Is The Basis For The Estimate of 1.5 Tons/year Emissions Reduction?

This estimate of emissions reduction is an approximation of typical/average results, used to convey relative magnitudes of various Actions, not predictions of actual results of a household’s insulation and weatherization. According to MassEnergize Carbon Calculator Methodology, 3.281 pounds of emissions are saved per year through various weatherization measures applied in the average Massachusetts single-family, income-eligible homes (taking into account various fuel types). This is calculated with estimates from the Technical Reference Manual used for the evaluation of Mass Save programs and from a 2018 evaluation study.

The chart at this link shows some of the key savings estimates.

Homeowners who maximize the insulation they install through Mass Save and/or other contractors may save more than the above estimates, which are for the traditional Mass Save residential program.

Lat Updated 3/15/26

Testimonials

Over 30 years ago my house was built with state of the art efficiency. When we bought it we were thrilled with the triple paned…

Even a well insulated house can be made better! For free.

Submitted by: Judith Aronstein

Thanks to the Energize Acton Energy Tour at David Martin's house we made the decision to move forward with heat pumps. David became our energy…

Happily insulated!

Submitted by: Carolyn Platt

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