Ductless vs. central — ductwork decides it

The honest decision tree starts with ductwork. Ductless puts a head in each room, so every room holds its own setpoint with no ducts to leak. A central system runs one thermostat, so only that room hits setpoint while the others drift hot and cold, and its attic ducts lose ~20–30% of the air (ENERGY STAR). No ducts → ductless; good ducts → central is usually cheaper.

Two identical three-room houses compared side by side. The left house, labeled ductless mini-split, has a wall-mounted head in each room fed by thin refrigerant lines from one outdoor unit, and each room holds its own setpoint (72°, 68°, 70°) — independent per-room zoning, no ducts, nothing to leak. The right house, labeled central ducted, has one air handler on the attic floor feeding a supply trunk through the attic that drops to a ceiling register in each room. There is a single thermostat in the middle room, so only that room is held at its 70° setpoint while the others drift — one room reads 74° (warmer) and another 67° (cooler) — the classic hot-and-cold-spots problem of a single zone. Small red arrows show air leaking from the attic ducts, noting a typical duct system loses about 20 to 30 percent of its air. A bottom strip advises: no ducts, an addition, or an older home favors ductless; good existing ducts favor central; and whole-house multi-zone ductless can cost as much as or more than a ducted system. — Source: ENERGY STAR (duct leakage 20–30%); DOE Energy Saver; ACCA Manual J/D (single-zone distribution)

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Two identical three-room houses compared side by side. The left house, labeled ductless mini-split, has a wall-mounted head in each room fed by thin refrigerant lines from one outdoor unit, and each room holds its own setpoint (72°, 68°, 70°) — independent per-room zoning, no ducts, nothing to leak. The right house, labeled central ducted, has one air handler on the attic floor feeding a supply trunk through the attic that drops to a ceiling register in each room. There is a single thermostat in the middle room, so only that room is held at its 70° setpoint while the others drift — one room reads 74° (warmer) and another 67° (cooler) — the classic hot-and-cold-spots problem of a single zone. Small red arrows show air leaking from the attic ducts, noting a typical duct system loses about 20 to 30 percent of its air. A bottom strip advises: no ducts, an addition, or an older home favors ductless; good existing ducts favor central; and whole-house multi-zone ductless can cost as much as or more than a ducted system.

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    <img src="https://remodelcalculators.com/api/figure-embed/ductless-vs-ducted-distribution" alt="Two identical three-room houses compared side by side. The left house, labeled ductless mini-split, has a wall-mounted head in each room fed by thin refrigerant lines from one outdoor unit, and each room holds its own setpoint (72°, 68°, 70°) — independent per-room zoning, no ducts, nothing to leak. The right house, labeled central ducted, has one air handler on the attic floor feeding a supply trunk through the attic that drops to a ceiling register in each room. There is a single thermostat in the middle room, so only that room is held at its 70° setpoint while the others drift — one room reads 74° (warmer) and another 67° (cooler) — the classic hot-and-cold-spots problem of a single zone. Small red arrows show air leaking from the attic ducts, noting a typical duct system loses about 20 to 30 percent of its air. A bottom strip advises: no ducts, an addition, or an older home favors ductless; good existing ducts favor central; and whole-house multi-zone ductless can cost as much as or more than a ducted system." width="800" height="500" style="width:100%;height:auto;border:0" loading="lazy">
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