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Insulate & Weatherize to the Max

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Home Energy

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Cost

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Most households in Acton have some insulation, but many need more to save energy (and money on their electric 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 perspective, an older home may have 250% greater air infiltration than a newly constructed one; that is a lot of cold air entering a home, making 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” tab. Only a few Actions (including EVs and the transition to heat pump technology) can reduce emissions by this much.

How to tell if walls are properly insulated and air sealed? Visit the “Acton Saves Energy” page to schedule a no-cost Home Energy Assessment (or energy audit) through MassSave. 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.

UPDATE: As of 2023, you may also contact a volunteer Acton Energy Coach with this Coaching Request Form.

During the assessment, the Energy Specialist may install, at no cost to you, LED bulbs, smart power strips, programmable thermostats, etc. Similar products may be available at no cost to renters at https://www.poweredbyefi.org/masssave_oracle/products/shop-all-products.html (sort by PRICE to see the no-cost items) and LED light bulbs are also available to electricity customers at no cost at: https://www.poweredbyefi.org/masssave_oracle/free-lighting-kits.html (but these offers may change so check these out now).

Take advantage of money saving incentives. MassSave, the energy efficiency program sponsored by electric and gas utilities and the Commonwealth of MA, offers a rebate that covers at least 75% of the cost of 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 MassSave 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 buildings in Acton to to make all feasible investments over time to reduce carbon emissions sufficiently. Homeowners, with support from the Town, state, and federal governments, will need to assess not only maximizing insulation and energy efficiency, but other Actions, as well: installating heat pumps, going 100% renewable for household electricity (via Acton Power Choice GREEN and/or on-site solar), switching to EV driving, and energy storage (battery) systems.

Maximizing insulation and weatherization is an easy and affordable way to “plug in” on 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), insulation and weatherization will also cut that installation cost by reducing the overall heating and cooling load (which reduces the size of the heat pump required; e.g., moving from a 4-ton to a 3-ton capacity system can mean a system cost reduction of $1,000–$3,000).

Steps to Take

1. Start with the MassSave 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, review basic efficiency recommendations and rebates, and receive an estimate of potential cost savings from insulation and other measures. (This process was started to address COVID lockdowns and may change.) If you are a renter, go to https://www.eversource-ma.com/renters/ and also see the “Savings for Renters” Action here on EnergizeActon.

2. To prepare for your Home Energy Assessment (energy audit), you may consult a volunteer Acton Energy Coach with this Coaching Request Form. You may also use the Cool Climate household carbon emissions calculator. This provides 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.

3. Schedule an in-person Home Energy Assessment. Once you are comfortable with protocols for COVID-19, you can call a MassSave Home Performance Contractor (HPC). The Acton Climate Coalition (with MassEnergize) is working to develop partnership(s) with one or more Home Performance Contractor(s), but in the meantime, you can review the MassSave list of all the HPCs that cover our area. To sign up for the MassSave Home Energy Assessment, have your electricity and natural gas account numbers ready, and if asked, say Energize Acton referred you.

4. If you are planning an addition or renovation project, look into MassSave’s alternative program offering for that process.

5. 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 PPA, a Power Purchase Agreement); and EV (electric vehicle) charging stations. (Some HPCs may offer more of these options than others.)

6. 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 MassSave 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 MassSave rebates for work performed. Have the final work examined by MassSave inspectors, and if needed, by local building or electrical inspectors.

7. If you elected 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. 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.) Also, please take the Zero Emissions Pledge to stop burning fossil fuels — as soon as you are ready to (or have to) replace existing fossil-fueled (gas, oil, or propane) equipiment.

8. Let us know how it went! Please write a Testimonial on the Energize Acton website.

Deep Dive

To help “bring net carbon emissions to zero as quickly as possible,” what questions should I ask my MassSave contacts?

To look into your options within the MassSave program, you may contact a volunteer Acton Energy Coach with this Coaching Request Form. When speaking with MassSave, first ask your Energy Specialist and MassSave 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 MassSave 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 MassSave; 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 MassSave inspectors, and if needed, 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 MassSave 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 MassSave and contractor personnel for suggestions in these areas, as well. Check out the relevant Energize Acton 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 (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 heat recovery ventilation.

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 MassSave programs and from a recent evaluation study.

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

https://www.actonclimatecoalition.org/wp-content/uploads/2021/05/2021-04-28_MassSave_wx_savings-eval.jpg.)

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.

Nerdly metrics: how does the electricity emission factor affect the emissions reduction estimates?

MassEnergize uses an electricity emission factor of 580 Lb/MWh from MassDEP. Energize Acton converted to metric tons using 2204.62 pounds/metric ton. Notes on electricity emissions factor: The DEP factor of 580 Lb/MWh is for Massachusetts as of 2017. Since that time, Energize Acton estimates that the emission factor should have dropped by about 11% through 2021, to 517. This is based on trends of ISO-NE’s average emission factor for 2018 and 2019, and then adjusted for remaining years based on the increase in the RPS Standard (2% per year). The APC Standard electricity should be about 12% lower than 517, reaching about 454 Lb/MWh, based on its additional 10& renewable content above RPS. Based on these trends, the emission reduction estimates for all of the Energize Acton Actions linked to electricity use could be improved further, to reflect the change in emission factor from 580 to 454 (from 3.2 to 2.5). However, Energize Acton is not making this change for two reasons: (1) the ISO-NE factors for 2017 — 682 Lb/MWh average and 654 marginal — are higher than the 580 MassDEP factor and better represent the regional wholesale market from which Acton Power Choice buys electricity; and (2) we want to use consistent impact estimates to allow future comparisons with other MassEnergize towns.

UPDATE: As of 2023, you may also contact a volunteer Acton Energy Coach with this Coaching Request Form. You may also email HomeEnergy@actonclimatecoalition for more information on insulation and other home energy actions.

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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