Is all-electric really cheaper than gas for Massachusetts multifamily?

It can be, and increasingly is. On a 12-unit new construction in Revere, the all-electric path came in at the lowest net construction cost of every option we modeled. It held a looser HERS ceiling of 45 versus 42 for gas, avoided the gas infrastructure, and pulled in $33,000 in Mass Save incentives the gas path could not.

Why does the gas path get a stricter HERS target than all-electric?

The code scores gas combustion as less efficient than a heat pump, so the gas building starts behind on the compliance scale. To compensate, it gets a lower HERS ceiling, 42 versus 45 on this project, which is a harder target. Meeting it requires a more efficient building everywhere else, mostly in the envelope.

What makes the gas path more expensive to build?

Three things stacked together. The stricter HERS target forces a heavier envelope, with heavier wall assemblies carrying more load. The gas system adds service, a meter, and in-unit piping to every floor. And Mass Save excludes gas heat, so the gas path forfeits incentives the all-electric path collects, $33,000 on this building.

When does gas still make sense for a new multifamily project?

When a commercial or process load requires gas service anyway, when an electrical service upgrade is unusually expensive, when gas distribution already exists from a renovation or earlier phase, or when an owner weighs decades of lower operating cost. The way to separate those cases from the default assumption is to model both paths to the same code target.

Why All-Electric Beat Gas on a 12-Unit Revere Build

On a 12-unit new construction in Revere, MA, the all-electric path hit a HERS ceiling of 45, pulled $33K in Mass Save, and came in cheaper than gas.

June 22, 2026

A developer building 12 units of new construction in Revere, Massachusetts came in certain that gas was the cheaper way to meet code. "Gas is always the budget play." We modeled both paths. On this building, the default answer was the expensive one. The all-electric path came in at the lowest net construction cost of every option we ran.

The Real Numbers

The project was a 12-unit new construction building in Revere, MA, and the goal was meeting the Massachusetts energy code. We ran a mixed-fuel gas path and an all-electric path side by side.

The first thing the model decided was the target. The mixed-fuel path capped the HERS ceiling at 42. The all-electric path was allowed a HERS ceiling of 45. That three-point difference does not sound like much, but it sets how hard every other system has to work.

To meet code on gas, the envelope had to do more. Heavier wall assemblies. The same double-pane low-E windows, but carrying more load. On top of that, the gas path added the service, the meter, and in-unit piping running to every floor.

The all-electric path got to stop sooner. It held at R-21 batt with R-5 continuous insulation, used in-unit heat pump water heaters, and qualified for $33,000 in Mass Save incentives. Net construction cost on the all-electric path came in lowest of every option we modeled.

The HERS Ceiling Math

Here is why the three points matter. A lower HERS ceiling is a harder target. The mixed-fuel path has to hit 42, which means the building must be more efficient to pass. The all-electric path only has to reach 45, a looser bar, so it can comply with less.

The reason gas gets the stricter target is the fuel. The code scores combustion heat as less efficient than a heat pump, so the gas building starts behind and has to make it up. The way you make it up is the envelope. Heavier walls, more glazing performance, tighter everything. Each of those is a construction cost the electric building does not have to carry.

Then the infrastructure stacks on top. Gas heat is not just the furnace or boiler. It is the service connection, the meter, and piping run to every unit on every floor. That is material and labor the all-electric building skips entirely, because the heat pumps and the heat pump water heaters run on the electrical system that is already there.

The incentive side closes the gap and then opens it the other way. Mass Save pays for electrification, so the all-electric path pulled in $33,000 the gas path could not touch. The electric building spent less to comply and then collected money for doing it.

When Gas Still Wins

The Revere result is not a universal verdict. There are projects where gas still earns its place.

Buildings with a load that needs combustion. A commercial kitchen, a shared laundry plant, or a process load may require gas service no matter what. If the line is in for another reason, the heating decision changes.

Tight electrical service or panel constraints. On a site where upgrading the electrical service is expensive or slow, the all-electric load can carry its own cost. That is a project-specific number worth checking before assuming electric wins.

Existing gas distribution. On a renovation or a later phase where the gas service and piping are already in place, the calculus shifts toward using what is built.

Operating cost over a long hold. Gas runs cheaper to operate in many markets, and an owner keeping the building for decades may weigh that against the construction premium differently than a developer selling at stabilization.

The Decision Framework

If you are building multifamily in Massachusetts and reaching for gas because it is the budget play, run the all-electric path before you commit. The instinct is a holdover from a code that no longer rewards it. The HERS ceiling, the envelope penalty, the gas infrastructure, and the Mass Save exclusion all point the same direction now.

The mistake on this project would have been pricing gas on the equipment and assuming the rest followed. The equipment was never the deciding line. The deciding lines were the stricter HERS target, the heavier envelope it forced, the piping to every floor, and the $33,000 the electric path collected that the gas path did not.

The default answer is not the cheap answer anymore, but it is not automatically the wrong one either. A different building, a different service constraint, or an existing gas line can move the result. The only way to know which path is cheapest on yours is to model both to the same code requirement before the budget is set, which is exactly what turned a 12-unit Revere developer's assumption on its head.