Do ducted heat pumps score better on HERS than ductless mini-splits?

Not necessarily. On the 112-unit Revere project we modeled, the ducted heat pumps and the ductless mini-splits produced the exact same HERS result with the same envelope, water heater, and appliance package. The energy model could not distinguish the two distribution methods, so the choice came down to cost and program rather than compliance.

Why do ducted heat pumps cost more than ductless mini-splits in multifamily?

The cost lives in concealed air handlers in every unit, sheet metal and flex runs through soffits and chases, and required duct leakage testing on every unit. None of that is needed for a ductless system, where the head conditions the room at the wall. On the 112-unit project, those items added up to a $312,000 premium that the energy model gave nothing back for.

Does a ducted multifamily system require duct leakage testing on every unit?

Typically yes. A ducted distribution system triggers required duct leakage testing per unit, which is a line item that scales directly with the unit count. A ductless mini-split system skips it entirely because there are no ducts to test, which is part of why the ductless path priced lower on the project we studied.

When is the ducted premium worth paying on a multifamily heat pump project?

When the ducts buy something the model does not score, such as concealed distribution an owner requires, better filtration and fresh air integration, or reach into a layout a single head cannot condition. The energy model will rate ducted and ductless the same in many cases, so the decision should be made on program and owner preference, confirmed by modeling your specific building.

Why Ducted Heat Pumps Added $312K on a 112-Unit Revere Project

On a 112-unit Revere project, ducted and ductless heat pumps landed the same HERS, but the ducted path added $312K with zero energy benefit.

June 08, 2026

If you are choosing a heat pump distribution system for a multifamily building, the energy model will not make the decision for you. We ran the compliance model on a 112-unit project in Revere with two distribution options on the table. Ducted heat pumps with concealed air handlers, or ductless mini-splits. Same envelope, same heat pump water heater, same appliance package. The only thing that changed was how the conditioned air reached the room. Both paths passed code. Both landed the exact same HERS result. One of them cost $312,000 more.

The Real Comparison

The building was a 112-unit project in Revere. The mechanical question was distribution, not equipment class. Both options were heat pumps. The choice was whether to run ducts to concealed air handlers in each unit or to hang ductless mini-split heads on the wall.

We held everything else constant so the comparison was clean. The envelope was identical in both runs. The heat pump water heater was identical. The appliance package was identical. The only variable that moved was the distribution method.

Both paths passed code. That part was never in question. What surprised the team was that both paths produced the exact same HERS number. The model could not tell the two distribution choices apart. From a compliance standpoint they were interchangeable.

So the question stopped being about energy and became about money. If the rating is identical, what is the ducted path actually buying. The answer was a six-figure premium that the energy model gave nothing back for.

Where the $312K Goes

The ducted path adds cost in places the energy model never scores. The first is the equipment itself. A concealed air handler in every one and two bedroom unit is more hardware than a mini-split head, and it has to live somewhere, usually in a soffit or a dropped ceiling that the architecture has to carry.

The second is the distribution. Sheet metal and flex runs have to travel through soffits and chases to reach each room. That is labor, material, and coordination that a ductless head does not need. The mini-split moves refrigerant to the head and conditions the room at the wall. The ducted system moves air through a tree of ductwork that someone has to design, fabricate, hang, and seal.

The third is testing. A ducted system in a multifamily building triggers required duct leakage testing on every unit. That is a line item that scales with the unit count, and on 112 units it is not small. The ductless path skips it entirely because there are no ducts to test.

Stack the concealed air handlers, the sheet metal and flex, and the per-unit duct leakage testing across 112 units and the premium came to $312,000. The model credited none of it. Zero energy benefit, real cost in the budget.

When Ducts Still Earn Their Cost

Ducted distribution is not waste on every project. There are buildings where the ductwork buys something the mini-split cannot, and on those the premium is worth paying.

Owners who will not accept wall-hung heads. Some luxury or design-driven projects rule out visible mini-split heads on aesthetic grounds. If concealed distribution is a hard requirement from the owner, the ducted premium is the price of the look, and the energy model is not the right place to argue it.

Units where filtration or fresh air integration matters. A ducted system can carry better filtration and integrate ventilation air into the supply more cleanly than a set of independent heads. On a project where indoor air quality is a priority, that integration can justify the cost.

Layouts a mini-split cannot reach. A unit with a long, chopped-up floor plan may need more heads than is practical, or may have rooms a single head cannot condition evenly. Ducts solve a distribution problem that head placement cannot.

Buildings where the soffits exist anyway. If the architecture already carries dropped ceilings and chases for other reasons, the marginal cost of running ducts through them shrinks, and the premium over ductless narrows.

The Decision Framework

If you are weighing ducted against ductless on a multifamily heat pump project, do not look to the HERS model to break the tie. On this 112-unit building the model rated the two paths identically, which means the distribution choice is a cost and program decision, not a compliance one. The ducts are not compliance. They are cost.

The mistake is assuming the more elaborate system must be doing more for the rating. It is not. The energy model scores the equipment efficiency and the loads, not how many feet of sheet metal carry the air. When two paths produce the same HERS, the extra hardware is buying program features, owner preferences, or distribution reach, and you should price it as exactly that.

Whether the $312,000 is worth it depends entirely on the building and the owner sitting across the table. One project needs concealed distribution and pays for it gladly. Another would rather keep the money and hang the heads. The energy model will not tell you which one you have, which is why we run the distribution options side by side before anyone commits to a duct layout.