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Ducted vs Ductless

How each works

A ducted system has an outdoor unit connected by refrigerant lines to an indoor air handler, which blows conditioned air through supply ducts and draws it back through returns. A ductless mini-split connects an outdoor unit to one or more wall, ceiling or floor heads, each with its own fan and coil. Slim ducted mini-split air handlers sit in between, serving a few rooms through short duct runs.

When ducted makes sense

• The house already has ducts in good condition and sized for heat pump airflow.
• You want one thermostat and hidden equipment.
• You are replacing a central air conditioner or furnace.

Heat pumps often need more airflow than furnaces, so a contractor should check that existing ducts and returns can handle it. Undersized ducts cause noise and poor performance.

When ductless makes sense

• No ductwork, such as homes with boilers, baseboards or electric heat.
• Additions, finished basements, garages or sunrooms.
• Rooms that are always too hot or cold.
• Homes where ducts run through cold attics and leak badly.

Each head serves its own zone, which can save energy when you heat only occupied rooms.

Efficiency differences

Ductless systems avoid duct losses, which can be 20 percent or more when ducts run through unconditioned spaces. Ducted systems with sealed, insulated ducts inside the conditioned space lose little. Ratings on paper often favour ductless, but real-world efficiency depends on installation and how you use zones. Compare SEER2 and HSPF2 on the AHRI certificate; see HSPF and SEER explained.

Comfort and air distribution

Ducted systems spread air through every room with supply registers, so temperatures are often more even. Ductless heads heat or cool their own room well but may leave closed-off rooms such as bedrooms cooler. In a typical house, one head per bedroom is common if bedrooms need full comfort. Ducted systems also make whole-house filtration and ventilation easier.

Appearance and noise

Ductless heads are visible on walls; some owners dislike their look. Ceiling cassettes and floor consoles help. Ducted systems hide equipment but can be noisier at registers if ducts are undersized.

Cost

Installed costs vary widely. One or two mini-split zones usually cost less than a full ducted system, but whole-home ductless with many heads can cost as much or more. Adding new ductwork is expensive and disruptive. See heat pump installation cost.

Maintenance

Ductless heads need their filters washed often, sometimes monthly in heavy use, and periodic professional cleaning of coils and blower wheels to prevent mould and odours. Ducted systems need filter changes and occasional duct inspection. Both need outdoor coil care.

Hybrid designs

Many homes combine both: a ducted heat pump for the main floors and a mini-split for a bonus room. Or a ducted system plus a ductless head in a room the ducts never served well.

Worked example

Figures below are illustrative examples (2026-10-29), not quotes or guarantees.

A 1,500 sq ft bungalow with baseboard electric heat considers two options. Option one: three ductless heads (living area 12k, two bedrooms 6k each) on a multi-zone outdoor unit. Option two: new ducts in the attic and a 2.5-ton ducted heat pump. If attic ducts lose 20 percent of heat, the ducted option needs about 25 percent more output to deliver the same comfort, and the attic work adds cost. The contractor may recommend ductless here.

Assessing your existing ducts

If the home already has ducts, ask the contractor to check static pressure, duct size and leakage before deciding. Ducts sized for a furnace sometimes cannot move the larger airflow a heat pump needs for cooling, which leads to noise and poor performance. Fixing a few undersized returns can make a ducted heat pump viable; a badly leaking system in an unconditioned attic may favour ductless heads instead.

Comfort differences

A ducted system delivers air through existing registers, so the look of the home does not change, and one thermostat controls the house. Ductless heads let each room run its own setpoint, which suits homes where some rooms are rarely used. However, a single head in an open area cannot easily reach closed bedrooms, and doors left shut can make those rooms cooler in winter.

Mixed systems

Many homes end up with a mix: a ducted unit for the main floor and a ductless head for a finished attic, addition or garage suite. Mixed systems can be the most practical answer when part of the house has good ducts and part has none. Ask for each zone's sizing separately so neither part is oversized.

Filters and upkeep

Ducted systems use a central filter that should be checked monthly in heavy-use seasons. Ductless heads have washable mesh filters behind the front panel that clog quickly in homes with pets. Both types need periodic coil cleaning by a technician. Dirty filters are one of the most common reasons for weak output.

Noise and appearance

Ductless indoor heads are visible on the wall and make a soft fan sound in the room. Ducted systems hide the equipment in a basement, attic or closet, though air moving through registers can be audible if ducts are undersized. If appearance matters, ask about ceiling cassettes or slim ducted units serving a few rooms.

Cost structure

Ductless costs scale with the number of heads, while ducted costs depend heavily on how much duct work is needed. Get both priced for your home.

FAQ

Can I use my old furnace ducts?

Often yes, after a contractor checks size, leaks and airflow.

Are ductless heads noisy?

Most are quiet on low speed; check the dB rating.

Which is better for allergies?

Ducted systems allow better whole-house filtration.

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