Article 29. Home Rule for Clean Heat (in new constructions)

"If we want clean air, lower construction costs, savings on our energy bills, and a stable climate for decades to come, we've got to start building for that future."

Olivia Walker, research associate at the Natural Resources Defense Council (NRDC)

UPDATE: Lexington's Home Rule Petition included as a new DOER program in MA "Act Driving Clean Energy and Offshore Wind" legislation, signed into law by Governor Baker on August 11, 2022!

Article 29 passed overwhelmingly at the Annual Town Meeting on March 22, 2021:

Home Rule Petition: Yes: 175, No, 7; Abstain: 5

Bylaw: Yes, 165; No: 13, Abstain: 7

Thank you to all our supporters!

Our 1st Panel Discussion


Watch the recorded 2/9 panel discussion in SustainbleLexington's YouTube Channel:

Check out our article in the Jan/Feb 2021 Colonial Times!

Final Colonial Times Clean Heat Article.pdf


Lexington Article 31 Home Rule for Clean Heat 2021

Summary of Article 29

At the Fall 2020-2 Special Town Meeting, Lexington voted near-unanimously to Declare a Climate Emergency, setting a goal of “ending town-wide greenhouse gas emissions as quickly as possible and no later than 2035.” In order to reach this goal, the Town must address onsite fossil fuel combustion in buildings, which accounts for 1/3 of Lexington’s greenhouse gas emissions. The Home-Rule for Clean Heat Article will address a necessary step in reducing these emissions as well as help protect the health and safety of its inhabitants and the natural environment.

In summary, passage of this article would authorize the Town 1) to file a home rule petition with the Massachusetts General Court for Special Legislation that would enable the Town to enact local bylaws that would regulate fossil fuel infrastructure in buildings and 2) to enact such a bylaw that would restrict fossil fuel infrastructure in new construction and major renovations.

This proposed Town bylaw would limit the installation of new fossil fuel (natural gas, propane, fuel oil) infrastructure so as to require new or significantly renovated buildings to use clean energy sources (electric heat pumps) with the following exemptions:

  • All cooking appliances;

  • Backup generators;

  • Outdoor cooking and heating;

  • Fireplaces;

  • Large central hot water heaters;

  • Life sciences laboratories and certain medical offices; and

  • Repairs to unsafe conditions.

Buildings currently connected to fossil fuel infrastructure would not be affected by the proposed bylaw. For major renovations, only the portion of the building being renovated would be affected by the proposed bylaw.

The proposed amendment additionally provides waivers for qualifying projects where non-fossil fuel infrastructure is currently not feasible.

This coordinated effort is a necessary and valuable incremental step in reducing pollution and investing in clean energy technologies for future generations.

What Article 29 does and does not do:

What Article 29 does

  1. It contains two provisions: (1) A Home Rule Petition asking the state legislature to allow the Town of Lexington to regulate fossil fuel infrastructure in new buildings and major (“gut rehab”) renovations, and (2) A bylaw that implements the regulation

  2. It starts a necessary step toward the Town’s goal of reducing our greenhouse gas emissions.

  3. Creates healthier new homes with dramatically less onsite fossil fuel combustion and significantly decreases operating costs for new homeowners over propane systems, the current choice of residential builders in Lexington.

What Article 29 does NOT do

  1. Does not require “net-zero” building standards (i.e., neither zero onsite carbon emissions or nor emissions offsets)

  2. Does not apply to existing buildings that might undergo minor renovations, additions or space/water heating system replacements

  3. Does not apply to the following, in a new building or major/gut renovation:

    • Gas piping for cooking appliances

    • Gas piping for back-up generators

    • Gas piping for outdoor appliances

    • Life science lab buildings

  4. Does not create Lexington’s own building code. Article 29 is complementary to the current state stretch code.

FAQ part 1. Regarding the proposed bylaw

Why is this important?

    1. Both Select Board (in 2018) and the Town Meeting (in 2020) pledged for Lexington's commitment to reach Net Zero between 2035 to 2043.

    2. We will not meet our Net Zero emission goals without reducing fossil fuel combustion in buildings, which account for about 1/3 of GHG (Greenhouse Gas) emissions.

    3. This is a critical step after the strong statement made with the passage of Article 16 in 2020 Special Town Meeting. (i.e., no on-site fossil fuel combustions in buildings where feasible).

    4. This proposal is a small but important first step. It will only affect about 100 new buildings and major renovations per year.

    5. With the earliest possible effective date of December 2022, this article will educate builders, architects and residents and help us plan for better and healthier future buildings.

    6. Those involved in development, including EDAC, have said numerous times that as long as regulations are feasible, they want to implement sustainable design because they know that their clients and their client’s employees want it.

    7. New/renovated buildings (to stretch code envelope standards) without onsite fossil fuel combustion are healthier and more comfortable. We want these high-performance buildings for our kids in school; Our residents and businesses need high-performance buildings too. This is a public health issue.

    8. It’s also an equity and social justice issue, as lower income communities are more often closer to larger natural gas infrastructure facilities and more vulnerable to gas leaks. Not working on plans to transition from a natural gas affects these communities.

    9. It is not hypocritical to promote electrification when many of us still use gas - we are in a hole, stop digging is the first step. We will continue to promote electrifying older homes as their old fossil fuel boilers age.

    10. Our community has taken many steps to mitigate the effects of climate change (as listed in the Climate Emergency Declaration in 2020). Eliminating Greenhouse Gas (GHG) emissions is a top priority for this global effort.

Why now? Why not let the state and its building code solve this?

    1. Fossil fuel systems in new buildings would lock in future emissions. Every building we build today with fossil fuel infrastructure defeats Lexington’s emission goals and will require an expensive retrofit in the future.

    2. It could take multiple years for the state to take action. Even with the current climate bill being negotiated, it's unclear what might be enforced or when. We have the opportunity to take a leadership role and act sooner.

    3. As cities, Boston, Cambridge, and Newton are pursuing similar paths for new construction. The Towns of Brookline and Arlington passed their home-rule petitions overwhelmingly in 2020, which this article is modeled after. Other towns are following suit.

    4. It will take at least 1.5 to 2 years before a home rule petition can take effect, which will provide ample time for the outreach, education and planning needed to start the transition away from fossil fuels in new buildings. We know that technology and pricing are no longer barriers; what needs to catch up is mindset.

    5. Home rule petitions were granted to Massachusetts cities and towns in 1966 and are quite common. Lexington and other municipalities have used home rule to accomplish their goals.

Why natural gas is not really clean:

The gas industry has spent millions of dollars trying to convince the public that gas heat is clean, healthy, safe, and cheap. In reality, it is none of these things.

  • Natural gas can be as bad for the environment as coal because it does more than emit CO2 during the combustion process. Unburnt natural gas is composed primarily of the far more potent greenhouse gas. Methane leaks plague every point of the natural gas chain, from production through consumption in our buildings. Studies show that, over time, the climate damage of natural gas is on a par with the CO2 emissions from burning coal.

  • Combustion from natural gas home appliances has been shown to severely affect air quality, emitting such pollutants as carbon monoxide, nitrogen dioxide, and particulate matter that lead to cardiovascular and respiratory disease.

  • Unburnt natural gas releases toxic air pollutants, most notably benzene, a known carcinogen.

  • Gas leaks can lead to explosions. In 2018, excessive pressure in natural gas lines owned by Columbia Gas resulted in explosions and fires that destroyed as many as 40 homes in Andover, North Andover, and Lawrence. In the wake of that tragedy, a team of experts concluded that Massachusetts is “rolling the dice” with gas safety. Lexington had its own experience of a gas explosion in 2005, when a home on Hancock Avenue exploded into a ball of fire because of a gas leak.

  • As of 2019, there were more than 15,000 reported active gas leaks in Massachusetts, including 144 in Lexington. Gas leaks are generally repaired only if they pose explosive hazards, but as mentioned above, a gas leak does not have to be explosive to present unseen climate and air quality hazards. Check this map to see if there is a gas leak near you (

  • Leaking gas also destroys trees. A 2020 study of the impacts of gas leaks on trees in Chelsea, MA found that dead or dying trees were 30 times more likely to have been exposed to methane leaking from gas pipelines, which displaced the oxygen in the soil, effectively suffocating plant life at the roots.

  • Gas repairs are expensive to ratepayers. Gas companies pass the expense of repairing gas leaks onto consumers, costing Massachusetts ratepayers $11- 60 million a year.

Why electrify our buildings when electricity is partially generated by fossil fuels like natural gas?

Electric buildings produce lower emissions than those directly fueled by gas and oil, because the way we generate electricity is rapidly becoming greener, as utilities incorporate more wind and solar to power the grid (currently 18% renewable in Massachusetts, increasing by 2% each year). This is especially true in Lexington, where most residents have 100% renewable electricity through the Town’s Community Choice Program.

Who will be affected by the proposed bylaw?

Approximately 100 new buildings and major renovations each year.

The expected effective date is no earlier than December 2022.

Exemptions in the article:

This proposed Town bylaw would limit the installation of new fossil fuel (natural gas, propane, fuel oil) infrastructure so as to require new or significantly renovated buildings to use clean energy sources with the following exemptions:

  • All cooking appliances;

  • Backup generators;

  • Outdoor cooking and heating;

  • Fireplaces;

  • Large-building central hot water heaters;

  • Life sciences laboratories and certain medical offices; and

  • Repairs to unsafe conditions.

Why exempt cooking appliances?

We decided to start with space heating and hot water, which make up 80% of home energy use, and to focus on consensus building.

Although gas cooking is a small part of carbon pollution, many people have already made the switch to induction stove and/or electric grills, and been very happy with their superior performance, speed, ease of control, cleanness, and safety.

Professional chefs are embracing induction stovetop as well: besides better efficiency and temperature control, there's no more worry of stuff caught on fire or sweating over the fire heat.

Another factor we considered was that cooking appliances are a much smaller investment than HVAC or hot water systems, and likely an easier decision to make.

For these reasons, we think many people will choose clean electric cooking technologies, like many people have bought electric cars.

Why exempt life science labs?

The exemption for labs is due to their periodic need for very high ventilation rates and the feasibility of providing that much heated air with a heat pump. It’s not a subsidy for labs; it just reflects the limitation of current technologies.

Why try to pass the home rule and new bylaw at the same time?

It is necessary to provide the state with clarity about what the Town is planning to enact if/when given the ability.

This is consistent with Arlington’s fall 2020 Town Meeting when they overwhelmingly passed two very similar actions with one vote in Nov 2020.

Brookline’s fall 2020 Town Meeting also overwhelmingly passed a similar petition, which included the request to enact a similar bylaw they had previously overwhelmingly passed.

It helps our supportive legislators (which partially overlap with Arlington) argue in favor of this legislation, because there is uniformity and clarity in what multiple towns are looking to accomplish, a petition/home rule AND a bylaw.

Why do we have to “require”? Won’t market forces be enough?

  • Without regulation, many new homes and major renovations will continue to be hooked up to fossil fuels, as they have always been, and as a result they will contribute to climate change and require costly retrofits in the future. (Currently the fuel of choice by builders for many new homes in Lexington is propane, a high emitting and expensive fossil fuel.)

  • Climate change is a systemic problem that requires systemic solutions.

  • Regulation pushes the adoption curve by providing certainty in the market and levels the playing field for all stakeholders.

  • While the state (DOER and MassCEC) and Mass Save have been offering generous incentives, rebates, and interest free loans for homeowners who chose Clean Heat technologies, and various training programs for building professionals and contractors, this is a relatively new and unfamiliar territory to many. Article 29 will accelerate adoption of Clean Heat technologies and reduction of carbon emissions.

How will this affect our ability to build affordable housing?

  • Lexington’s new Farmview and Fairview affordable housing buildings are already leading the way, creating healthier, more resilient, near-zero emissions, all-electric buildings.

  • Installation costs for all-electric systems can be lower because one system replaces two systems in a conventional, fossil-fuel heated building. Rebates and other incentives further decrease the initial cost.

  • The lower long-term maintenance and operation costs are also saving tenants and LexHAB money. (More in testimonials.)

Neighboring municipalities with decarbonization bylaws and plans:

  1. Lexington:

  2. Arlington

  3. Brookline:

  4. Boston: Net Zero Action Plan (2019) p33-53 Buildings

  5. Cambridge: Sustainable Development policies

  6. Newton: in the planning phase of home-rule petition

  7. Concord: in the planning phase of home-rule petition

  8. Somerville Zoning Ordinance and click on the pdf:

    • Residential: search "net zero" to see incentives for better buildings,

    • Commercial: "9. Development Standards" under 8.3. OVERLAY DISTRICTS Master Planned Development (MPD), on page 389

  9. Action is planning a similar proposal as Article 29.

  10. San Jose set to become largest U.S. city to ban natural gas in almost all new construction (12/2020)

FAQ part 2. Regarding Clean Heat technologies

Do heat pumps work in New England's climate?

    1. Heat pumps work in New England and they are not more expensive to run.

    2. In recent years, newer technology ccASHP (cold climate Air-Source Heat Pumps) with high HSPF (Heating Seasonal Performance Factor) developed by major brands (Mitsubishi, Carrier, Bosch, and LG) work beautifully in New England weather without any fossil-fuel backup.

    3. Good insulation (weatherization) is important.

    4. With cooling and heating combined into one system, it reduces the cost for installation, maintenance, and replacement.

    5. Installation costs are further reduced with state rebates and incentives.

How many buildings in Lexington use heat pumps? What are their experiences?

Installation data from Eversource, based on rebates paid under Mass Save:

Year Central/ducted ASHP Mini-split/ductless ASHP Hot water heat pump

2018 48 84 5

2019 53 107 6

2020 27 125 12

TOTAL 128 316 23

In addition, all recent town construction projects (Hastings, Fire Station, Children's Place, Visitor Center, etc.) and LexHAB homes (Fairview and Farmview) use electric heat pumps for space heating and cooling.

See more Clean Heat building examples and testimonials

Contact us if you have any questions or would like to share your experience.

Is it affordable to install a heat pump? What do building professionals say?

  1. Cold climate air-source heat pump systems (ccASHP) are affordable and already a popular alternative to fossil fuel heating systems.

  2. Because only one system is needed, rather than a separate furnace and air conditioner, they can be comparable or cheaper to install even before rebates.

  3. “Doing it right the first time” is better than requiring expensive retrofits to these homes later.

  4. Various rebates available (details on the Why Clean Heat? page) will further reduce the cost for ccASHP installation.

  5. Example quote from Net Zero Heating and Air Conditioning (, an installer serving Lexington:

Theoretical approx 4500 sq ft home, 2 floors, 1 zone/air handler/furnace for each floor (in basement for 1st floor, in attic for 2nd floor). Includes all ductwork (supply and returns), pads, etc.

    • Heat pump systems installed: Cost $28,167 (before rebates)

    • Gas furnace + AC installed: Cost $29,889

Installation costs are further reduced with state rebates and incentives.

How much will it cost to run?

For heating alone, heat pumps cost significantly less than electric baseboards or propane, on par with oil, but somewhat more than natural gas. (Some studies have shown an estimated additional cost compared to gas from $120 to $315 annually).

However, when considering the potential future increase of gas prices and the lower cooling cost of heat pumps versus traditional AC, heat pumps will be on par with gas by 2026.

Many users have found the overall running cost of heat pumps affordable, about a wash compared to natural gas, and lower than oil or propane.

See more details and comparisons on our Why Clean Heat page.

Can our electric grid handle the load?

Yes! Electrical demand is currently declining in New England due to both onsite solar energy generation and gains in energy efficiency through retrofits such as LED light bulbs for streetlights. There are declines in both annual and peak demand, and these declines are expected to continue.

Furthermore, the proposed bylaw will affect such a small fraction of buildings on the grid (<1% turnover in any one year, even if adopted across the entire New England grid territory), that it should not have an appreciable impact on the power grid, which already has year-on-year variation exceeding 1%.

While peak consumption is already a significant challenge to manage, it is currently a summer problem when AC kicks in on hot days. In the winter, the bigger problem is actually natural gas shortages, which should be slightly alleviated by this policy.

Will homes need additional electrical capacity to be all-electric?

No. The capacity needed for new cold climate air-source heat pumps in new homes in the winter is roughly the same as older central ACs in the summer. Ground source heat pumps use even less.

What will happen during power outages with electric heat pumps?

  1. During electricity outage, fossil fuel heating systems will stop working as well because they depend on electricity to distribute forced hot water or forced hot air.

  2. Because of the superior insulation and increased resilience of new homes, they are much less likely to have significant temperature drops and thus, less likely to need a backup generator for heat during outages of a few hours.

  3. For power backup during prolonged power outage, one can use:

    • Power wall batteries (with or without solar panels), or

    • A generator (which run on fossil fuels like gas, propane, or diesel)

With the right size, either power wall batteries or generators can run heat pumps.

  1. Power walls are a better solution for larger homes because:

    • Batteries are cleaner and do not pollute,

    • When paired with solar panels, power walls will be a lot more versatile and require less usage compromise. There are homes designed to operate off the grid on a regular basis.

    • Fuels for generators may be difficult to get during prolonged power outage, as happened in Texas.

  2. If a new homeowner wants backup power, the additional cost of a larger system is not a big driver after fixed costs like engineering, foundation pads, trenching, special switchgear in the electrical closet, landscaping.

  3. It turns out that the health risks are much greater for power outages during extreme heat waves. So if you want to have air conditioning during a power outage, you'd want to size the backup power large enough for the heat pump (which is also the air conditioner).

  4. On a related topic, the recent blackouts in Texas were primarily caused by lack of winterization and problems with suppliers of natural gas. Not renewables.

Isn't better insulation more important than electrification?

Both insulation and electrification are important, and we need to do both.

In fact, in order to qualify for MassSave rebates and interest free loan for your heat pump installations, a free energy assessment is required.

Article 29 is limited in the scope of electrification in new buildings and major renovations, which are normally well insulated under current stretch building code. Of course, we know it can be better.

Improving building code insulation standards is important and needs to be addressed either at the state level or in a subsequent warrant article for that specific purpose.

A smoker can exercise and eat healthy, but it's not a substitute for quitting smoking. Better insulation will reduce energy use but cannot replace the benefit of quitting fossil fuels.

Which systems are more resilient?

A boiler/furnace is a single point of failure. If your boiler or furnace fails at midnight, the whole house goes cold. You need to call for a repair person to come to the house at midnight.

Heat pump design for a typical size new Lexington home will have more than one heat pump system. If one of your heat pumps fails, you still have another one or more providing heat. Therefore, heat pumps are naturally redundant. The repair call can wait until the morning. It is wonderful to have built-in backup.

Is there a list of cold climate air source heat pumps (ccASHP) that work in Massachusetts weather?

NEEP (New England Energy Efficiency Partnerships, located on Hartwell Ave, Lexington) compiled a comprehensive list of ccASHPs:!/product_list/ and you can sort hundreds of products by clicking on list view.

HSPF (Heat Seasonal Performance Factor) is a good indicator of efficiency.

Here is a MrCool video explaining how ccASHPs work in extremely cold weather. The example is a ducted central system. Ductless mini split systems are similar.

Do air source heat pumps lose efficiency in cold weather?

Many cold climate air-source heat pump models can perform at 100% capacity at 0°F (see chart below).

According to Hanscom AFB data:

  • 99.6% of the hours of the year, Lexington's temperature is higher than 3°F.

  • 99% of the hours of the year, Lexington's temperature is higher than 9°F.

  • The coldest day in Lexington over the last 15 years was 2/14/ 2016. It is the only day in the last 15 years when the average temperature for the day was below zero. (-0.9°F)

Most building codes are set based on ASHRAE standards (American Society of Heating, Refrigerating, and Air-conditioning Engineers), which recommends using either the 99.6% or 99% temperature as the heating design temperature.

What this means is that the latest generation of air-source heat pumps are capable of delivering 100% rated capacity down to Lexington's 99.6% heating design temperature. For ground source heat pumps, the outdoor temperature does not matter.