Heat Pump Dryers Let a 170-Unit Worcester Job Skip Spray Foam

A washer and dryer let a 170-unit job skip spray foam. On this Worcester, MA townhome project, the first wall design called for closed-cell spray foam. It performs well, but across 170 units, spray foam gets expensive fast, and the client wanted that cost down. We found the savings in a place most teams never look when they are trying to pass energy code: the laundry room.

The Real Project

The project was a 170-unit townhome development in Worcester, Massachusetts. The first wall design called for closed-cell spray foam. Nobody was arguing about whether it works. Closed-cell spray foam insulates well and air seals well, and it gives the energy model a strong wall to start from.

The problem was the price tag at scale. One townhome's worth of spray foam is a line item. Across 170 units, spray foam gets expensive fast. The client wanted that cost down, and the wall was the obvious place to look.

So we switched to fiberglass batts with exterior insulation. It is still a well-insulated wall, and it is cheaper. But it gave up a bit of energy performance compared to the spray foam design. That gap had to be made up somewhere, or the building would not pass.

We found it in the laundry room. Each unit got an LG WashTower with a heat pump dryer. The building passed code with no spray foam, and the total cost went down. The dryer costs more up front, but the overall savings more than covered it.

Why Spray Foam Gets Expensive at Scale

Spray foam earns its place on a lot of projects. Closed-cell foam fills the cavity, adds rigidity, and cuts air leakage in the same step. In an energy model, that shows up as a strong wall and a tight building. The question is never whether spray foam performs. The question is what you pay for that performance and whether you can buy the same result for less.

On a townhome job, the wall area adds up quickly. Every unit has its own exterior walls, and the spray foam goes into all of them. A cost that looks reasonable on one unit gets multiplied 170 times. That is where the premium lives. It is not one expensive decision. It is the same expensive decision repeated across the whole project.

Fiberglass batts with exterior insulation take a different route to a good wall. The batts fill the cavity at a lower cost. The exterior insulation wraps the outside of the framing, which helps with the heat that would otherwise move through the studs. The result is still a well-insulated wall, and it is cheaper to build.

It is not identical, though. Compared to the spray foam design, the batts and exterior insulation gave up a bit of energy performance. In a performance model, a small loss like that does not disappear. The building has to hit the same target either way, so every bit of performance you give up in the wall has to come back from somewhere else in the model.

This is the moment where most teams reach for the envelope again. Thicker exterior insulation, better windows, more air sealing. Those moves can work, but each one adds cost back into the same wall you just tried to save money on. Spend enough of them and the savings from dropping spray foam start to vanish.

How a Heat Pump Dryer Closed the Energy Code Gap

The energy model does not only count walls. It counts the whole building, including the appliances people use every day. That opens a door most teams never walk through. If the wall gives up a bit of performance, you do not have to win it back in the wall. You can win it back anywhere the model counts energy.

The laundry room is one of those places. A standard dryer is one of the bigger energy users in a home. A heat pump dryer does the same job with far less energy, because it recycles heat instead of making all of it from scratch. Each unit on this project got an LG WashTower with a heat pump dryer, and it used far less energy than a standard dryer.

That reduction is what closed the gap. The energy the wall gave up was made back in the laundry room, one unit at a time. Across 170 units, a small improvement in every unit adds up the same way the spray foam cost did, except this time it works in the project's favor.

The dryer did more than help the model. It also changed what the building needed around it.

It got rid of the dryer vent. A heat pump dryer does not need to push hot, moist air outside the way a standard dryer does. No vent means no hole through the exterior wall for every unit, and one less penetration to detail and air seal.

It did not need a 240V circuit. A standard electric dryer typically needs its own 240V circuit. Taking that circuit out of each unit is less wire and less electrical work.

It installed faster. No vent to run and no 240V circuit to pull means less work in every laundry room. On a job this size, faster installs repeated across every unit matter to the schedule.

Put it together and the math is simple. The dryer costs more up front. But the wall got cheaper, the vents went away, the 240V circuits went away, and the installs went faster. The overall savings more than covered the higher price of the dryer, and the total cost went down.

When Spray Foam Still Wins

None of this means spray foam is the wrong call. It means spray foam is one option, and it should earn its place on the numbers. There are projects where it does.

When the wall is doing more than insulating. Closed-cell spray foam air seals and insulates in one step. On some assemblies, getting that from one material is simpler than coordinating batts, exterior insulation and separate air sealing work.

When the appliances are already efficient. If the design already has efficient laundry and other efficient equipment, the appliance lever may already be used up. Then the performance has to come from the envelope, and spray foam may be the cheaper way to get it there.

When the gap is too big for one appliance. On this job, the wall gave up a bit of energy performance. If a wall change gives up a lot, one appliance swap may not close it. The model tells you how big the gap is before anyone signs a purchase order.

When the unit count is small. The spray foam premium hurt here because it was multiplied across 170 units. On a smaller project, the premium is smaller, and the effort to redesign the wall may not pay for itself.

The Decision Framework

Start with the expensive line items, and ask what they are buying. On this job, spray foam was buying wall performance. That performance was worth something, but the same result was available for less by splitting the job between a cheaper wall and a better dryer.

Then look at the whole model, not just the envelope. When you give up performance in one place, the cheapest place to win it back is often somewhere you were not looking. Here it was the laundry room. On another project it might be something else entirely. You do not know until you run the numbers.

Count everything the change touches. The heat pump dryer did not only cut energy. It removed the dryer vent, removed the 240V circuit, and installed faster. If you only compare the dryer's price to a standard dryer, it looks like a bad deal. If you compare the whole package, the total cost went down.

No two projects carry the same walls, the same units or the same budget. A swap that saved money on a 170-unit Worcester townhome job could fall flat on a different building. The only way to know which trade works on yours is to model it before the wall design gets locked in.