Article 17. Sustainable Hartwell: Building for the Future

The Clean Heat Lexington Alliance supports the Town’s commitment to increase Lexington’s commercial tax base by attracting Life Science and Lab development to the Hartwell area. The objective of this article is to achieve the desired development while reducing emissions by encouraging Hybrid HVAC systems with Incentive Zoning.

Current zoning in section 135-7.4.4 has two height-based Incentive Zoning clauses. The clause in Section 7.4.4.2. requires buildings over 6 stories to use all-electric (no on-site combustion) HVAC systems. A typical six-story office building is about 65 feet tall. A typical six-story Life Science & Lab building, because of the special ceiling height requirements needed to accommodate its equipment, would be about 110 feet tall. By using the “6 story” limitation, rather than a “65 ft.” limitation, Section 7.4.4.2. effectively exempts taller life science/lab buildings from this all-electric/no combustion HVAC provision.

This addition (7.4.4.3) provides that buildings over 65 ft shall use Hybrid HVAC (Clean Heat as the initial heating source, supplemented with on-site combustion to meet Life Science & Lab needs). As a result, it would include Life Science & Lab buildings in the Incentive Zoning clauses of the bylaw.

Hybrid HVAC systems are already being included in Life Science & Lab buildings in the Greater Boston area, including multiple projects by different developers, totaling millions of square feet of lab space. Hybrid HVAC meets the building’s performance needs and developer’s economic targets (by reducing construction and lifetime operation costs), as well as significantly reduces the building’s emissions. As more and more developers are building or planning to build this way, it's becoming the industry's best practice.

While Lexington and other municipalities have long used Incentive Zoning to encourage affordable homes and dense developments with more open space and better-than-building-code buildings, its use in the context of encouraging lower emission buildings is a recent development. Earlier this year, the Attorney General's Office (AGO) approved Lexington’s Incentive Zoning language in Sections 135-7.4.4.1 and 7.4.4.2 (passed in fall 2020 with no opposition or concern from property owners or Town staff), demonstrating the AGO's acceptance of incentive-based building requirements and electrification of HVAC in zoning bylaws. The proposed addition in 7.4.4.3 merely adds further specification to this existing Incentive Zoning language.

Because of the overwhelming interest in improving sustainability standards for commercial projects during the 2021 Annual Town Meeting, and because the wider community has demonstrated Lexington’s willingness to take action to reduce emissions in our new buildings by way of the Home Rule for Clean Heat (i.e., reducing on-site fossil fuel combustion for heating), we are hopeful that Town Meeting will support this addition as well.

There are developers that don't want to consider Hybrid HVAC systems for buildings that reduce lifetime costs and emissions. But there are developers that want to do this and ARE doing this. The latter are the kinds of developers we should want in Lexington. We should want projects that are thinking of the future, using best practices to reduce onsite emissions. If we get the redevelopment on Hartwell that is envisioned (2-4 times more square footage) with energy intensive life science labs, we are going to significantly increase the town's overall emissions, on the order of 25-60%.

We've got to be thinking of the future and phase out the burning of fossil fuels in our buildings. Starting now.

The intent of Article 16 from 2020-2 STM, which resulted the current new zoning dimensions for Hartwell is to double, triple, or quadruple the amount of commercial space on Hartwell Avenue as quickly as possible, with the hope and expectation that these new, larger buildings will likely be Life Science & Lab buildings.

Town Meeting asked Town staff, Boards and Committees to consider climate change in all decisions and planning processes. How the Town handles the major redevelopment of the Hartwell corridor could arguably be one of the most important decisions that the Town makes with regard to impacting Lexington's emissions for decades to come.

Expanding Hartwell entirely with labs built to current code will result in increasing Lexington's total emissions by 25 to 60% and increasing Lexington's overall emissions due to natural gas usage by 70 to 160%! Would anyone consider that a success?

Now let's look at the Hybrid HVAC model - which says that by running non-combustion systems (e.g., heat pumps) first - you can reduce natural gas emissions by up to 90%. This is documented in reporting from four Boston and Cambridge lab designs mentioned on this site.

That means moving to Hybrid HVAC labs has the potential to reduce future Hartwell gas emissions by a factor of 4.8 and, when considered with the move to 100% renewable electricity, to reduce total future Hartwell Avenue emissions by a factor of 8.3 - LOWER than current emissions from today's buildings on Hartwell! This is exactly what we need to meet our emissions goals AND support new development, at the same time.

In the discussions with representatives with Boston Properties (a property owner/developer in the Hartwell area), they conveyed that they could meet a 15 Btu/h-sf minimum heating capacity with heat pumps for a life science project. Alexandria RE reported, at a webinar in the spring, that their Binney St lab/office project under construction in Cambridge has a heat pump capacity of 15 Btu/h-sf. A lab/office project at Landmark Center that is in the approval process is being designed with a heat pump capacity of 18 Btu/h-sf.

Other projects referenced (Landmark Center and Fenway Phase II) are also buildings with hybrid HVAC systems. Those projects chose to go with Hybrid HVAC systems not only because they were doable, but because they saved money over the lifetime of the building AND reduced emissions.

In May of 2020, NEEP (Northeast Energy Efficiency Partnerships) proposed an EZ (Energy Zero) Code that includes an HVAC requirement of at least 5 Btu/h-sf of heat pumps (air, ground or exhaust) for ALL buildings, including high energy intensity buildings, such as labs. The proposal’s “extensive vetting” includes review and input from: “Regional and national code professionals, nearly 50 Massachusetts-based design and engineering professionals, sixteen Massachusetts cities and towns, and various architecture and engineering trade associations”.

It's clear that a 5 Btu/h-sf minimum high efficiency electric-based heating capacity is a reasonable requirement.

1. Currently, emissions created by on-site combustion are not regulated by the building code at all. And even with passage of the new climate bill, there is no guarantee that this type of regulation will be included. Additionally, any building code changes and adoption will take multiple years. Meanwhile, without this addition, large Lab and Life Science buildings will be allowed to be built with 100% fossil fuel heating by right. Meaning, new project applications coming in now will not be subject to any potential future building code or bylaw and Lexington is not allowed to deny a lab building application based on the fact that it has 100% fossil fuel heating.

2. Incentive Zoning is a commonly used tool to encourage better development that benefits the community. In past years, Lexington has used Incentive Zoning for affordable housing and dense developments with more open space. The Attorney General's Office has specifically stated that, in terms of not relying on fossil fuels, "the Town may consider adopting incentive programs to nudge property owners in that direction.” (Read more on Incentive Zoning under Background.)

3. Without this addition, existing mechanisms including design guidelines, site plan reviews, and collaborative meetings, cannot enforce any reduction in greenhouse gas emissions. The proposed Incentive Zoning addition provides developers a predictability that they value in their design and application process, and will help property owners to avoid expensive retrofit in the near future or being stranded with a dinosaur HVAC system.

4. Just as Lexington has committed to consider Climate Change in everything we do, we need to ask the same from developers building in Lexington. With this addition, Lexington can expand Hartwell area lab space 2 to 4x while reducing greenhouse gas emissions, so that we can meet our goals for commercial development and greenhouse gas emissions reductions.

It makes sense to ask the question about impact on business development in town. However, it's pretty clear that any fear that this minimum standard, that is being exceeded in more and more other developments, might deter new development is not founded in sound logic with supporting data.

First Lexington has been identified as a “Platinum BioReady Community”, a top community friendly to life science development.

Next, consider that Lexington currently has a requirement in the Traffic Demand Management Plan that is costing developers approximately three dollars per square foot and that is NOT deterring development. Data from buildings in the area that exceed the Article’s standard show that Hybrid HVAC is, on average, cost neutral. By meeting or exceeding the standard proposed in the Article, property owners have the added benefit of advertising their development as a very high performing, sustainable building, ready to meet our Town and State emission reduction goals. The Globe recently covered that Moderna just leased a building with 15 Btu/h-sf of clean heat/heat pumps in the design “because it’s the most sustainable commercial lab building in Cambridge”. A lower emission building is going to be much easier to lease, especially to life science tenants.

Looking to the near future, developers seem to be taking notice of the risk of increasing gas prices and how developments that are less dependent on gas are lower risk. (Gas supply prices have more than doubled in the last year and will continue to rise, prices will be 30% more this winter compared to last winter). It seems smart developers are going to hedge that risk, they are taking note that any building 100% dependent on gas is going to be a really hard building to lease as natural gas prices rise. We shouldn't want our developments on Hartwell to sit empty in 10-15 years because they are too costly to run.

A recent NYT article about investors seeking greener buildings included investors saying: "What has changed in recent years is the perception of risk associated with climate change, prompting investors to steer money toward safer, higher-performing green assets." and “Five to 10 years ago, there was a lot of debate about sustainability, that, ‘It’s nice, but I don’t want to pay for it.’ Today, you don’t sacrifice returns for sustainability, you create returns with sustainability.”

BOTH development investors and life science tenants want lower carbon buildings. Buildings built to standards that lower the emissions from buildings are going to be MORE attractive not less. We've got to be thinking of the future and phase out the burning of fossil fuels in our buildings.

Both Boston and Cambridge have comprehensive zoning ordinances/bylaws that require better than code buildings and they are in the process of defining even more emission reducing zoning requirements. Somerville has Incentive Zoning, passed in 2019, requiring non-fossil fuel HVAC and Passive House-type certification for non lab buildings and LEED Platinum for labs.

Whether it's zoning in any of those municipalities or in Lexington, predictability is key for developers to build better buildings. If a developer comes in knowing what to expect, they can work with engineers with the right expertise and design the building to meet those expectations.

It's been pointed out that no other municipality has requirements for Hybrid HVAC, specifically. This is true, but at the same time, neither are they overhauling zoning in their largest commercial districts to allow a by right increase of buildable square footage by 2 to 4 times what is currently there, which would increase the entire Town's natural gas emissions multi-fold. To seize this unique opportunity is something our town should be proud of, not fearful of. Incentive zoning is not new. The Attorney General's Office approved Lexington's use of incentive zoning to encourage emission reduction in buildings, including non-fossil fuel HVAC for tall office buildings.

With this amendment, Lexington can expand Hartwell area lab space 2 to 4x while reducing greenhouse gas emissions. On the other hand, reliance on design guidelines, site plan reviews, and collaborative meetings, cannot enforce any reduction in greenhouse gas emissions. The proposed Incentive Zoning amendment provides a predictable mechanism for both developers and the Town to meet our goals for commercial development and greenhouse gas emissions reductions.

Yes. Good building design uses an independently operated ventilation system distinct from the heating/cooling equipment. The fans and other parts of the ventilation system that produce the needed air changes for the various types of lab needs can be reconfigured for varying uses without altering the systems that provide the heating capacity.

A Hybrid HVAC system required in this amendment differs only from an all-fossil fuel HVAC system in that first 5 Btu/h-sf of heating capacity much be supplied with Clean Heat. Above that minimum capacity, there are no restrictions on the heating source, amounts or intensity.

We have referenced here Lab and Life Science buildings with Hybrid HVAC being built by different developers in Cambridge and Boston. Boston Properties, a premier developer in the area and one of the largest property owners in the Hartwell district, spoke at this week’s Economic Development Advisory Committee meeting in support of Article 17 saying that Article 17 is a “smart, reasonable standard”, and a “good place to start.” (This article only requires a minimum heating capacity of 5 Btu/h-sf by Clean Heat.)

Projects in Boston have shown that they expect their 20-year net present costs to include Hybrid HVAC are millions of dollars lower compared to using traditional fossil-fuel only HVAC. Another project will add only 0.1% to the construction cost, while reducing onsite emissions for space heating by 93% with Hybrid HVAC.

Lab building engineers have commented that when designing for Hybrid HVAC, cost is not an issue, but in some cases, building site and size, such as rooftop space, can be when trying to maximize the non-combustion portion of Hybrid HVAC.

The advantage of Hybrid HVAC in labs is that we do not have to choose between economics and sustainability. We can have both.

Yes. Boston Properties, a major developer in the area, has plans for a potential project in the Hartwell district that they said could meet a minimum heating capacity with 15 Btu/h-sf of Clean Heat (no combustion). (This proposal only requires a minimum heating capacity of 5 Btu/h-sf.)

These kinds of requirements are often certified by the registered engineer or some other certified individual involved with the project, so the building department would just have to make sure those affidavits are received, much like they do with required HERS ratings or other detailed code requirements for projects. Town staff has indicated that they will require the engineer of record for each project to submit an affidavit submitted prior to, and at completion of, the building project to confirm the engineer has reviewed the work, and that the engineer certifies that the new building meets the building code and Lexington’s zoning bylaw.

The fact that developers don't know who the specific tenants are going to be for any new development is not relevant to this Hybrid HVAC addition.

Developers, however, will absolutely design a new building to accommodate a certain class of tenants. And they know the specifications that will attract the class of Life Science tenants. For example, the design goals for 325 Binney, Landmark, and Fenway Center Phase II are for a high percentage of lab space (60 or 70%) with the rest being office space, which makes it clear what the requirements are for their HVAC systems.

The heat pumps and the gas boilers of a Hybrid HVAC system are central resources connected to the ventilation system that delivers conditioned outside air with the standards required by lab / life sciences tenants and will be independent of who the clients are. While lab tenants are going to install highly specialized lab equipment in the buildings, that equipment is independent of the HVAC system.

Having a small percentage of the heat capacity of the central plant provided by a heat pump/non-combustion system is not going to constrain the types of specialized lab equipment tenants will want to install.

Heat/energy recovery systems are not included in this article as it has become an industry standard even in onsite fossil fuel combustion HVAC systems.

Heating system efficiency is measured by the system’s Coefficient of Performance (COP). This is the ratio of the useful heat provided to the amount of energy required to provide that heat. For example, the COP of an energy recovery system (ERV) is typically 0.7-0.8. This means the ERV has an efficiency of 70% to 80%. Electric resistance heating has a COP of 1.0. All heat pumps have COPs well over 1.0, with air-source heat pumps typically spec’d with COPs of 2 to 4 and ground-source heat pumps spec’d with COPs of 4 to 6.

RMI has recommended that any standard for a minimum clean heat should include only systems with COPs over 1.0, in order to avoid inefficient heating types.

If we are truly thinking of our students’ future, we should be looking to raise revenues to pay for a new high school AND limit our contributions to increasing emissions at the same time. We are NOT helping our young people if we finance their education by making the climate crisis worse for them.

Article 17 is consistent with the Home Rule petition for Clean Heat. Article 17 will establish a new clean heat standard for buildings over 65 feet in the Hartwell Commercial Manufacturing (CM) zoning district.

Specifically, Home Rule for Clean Heat, which would apply town-wide to all new buildings outside of the named exemptions, was written to be consistent with similar bylaws from Brookline and Arlington. The goal was to provide clarity of intent across multiple municipalities in the hopes of expediting the potential approval by the state legislature.

Article 17 is very specific to the HVAC systems of new buildings over 65 feet in the Hartwell area, much like the two existing Incentive Zoning clauses in Chapter 135 section 7.4.4. In addition, it only makes Clean Heat (no onsite fossil fuel combustion) stipulations for the first 5 Btu/h-sf of heating capacity in Life Science and lab buildings. There are no restrictions for any heating capacity over that or onsite fossil fuel combustion for purposes not related to building heating, such as emergency backup power generators, humidification, or process equipments.

To borrow one Town Meeting member's interpretation:

"It looked complicated when I first read it, but now I see that it's pretty straight forward.

For standard office buildings above 65 feet (i.e., 6 stories), section 135-7.4.4.2. already requires non-fossil fuel HVAC systems. It's assumed that office buildings have a "base" heating load of something in the neighborhood of 5 BTUs per square foot.

[The proposed addition] is simply requiring lab and life science buildings to also meet this same base heating load with non-fossil fuel HVAC systems. Anything over and above the base load can be met with fossil fuel systems. So [the addition] is just making the base heating load requirement uniform across all building types.

Once I thought of it this way, it seems pretty logical."

The Home Rule for Clean Heat bylaw exempts all lab buildings from the no on-site combustion for HVAC requirement while Article 17 requires a hybrid HVAC in lab buildings over 65 feet in the CM district.

The more specific language prevails over the more general. Article 17 modifies the lab exemption a) to the extent that there are special heat load requirements of a lab, b) in buildings above 65 feet, and c) in the CM district only.