Ductless vs central (ducted) systems, side by side
Your ducts decide: homes with sound ductwork usually stay central; homes without ducts (pre-war, baseboard, townhome) usually go ductless rather than buy a $5,000–$15,000 duct retrofit. Zoning preference and visible-head tolerance settle the remainder.
| Dimension | Ductless mini-splits | Central ducted system |
|---|---|---|
| Needs ductwork | No | Yes (existing or built new) |
| Zoning | Per head, standard | One zone unless dampers added |
| In-room visibility | Wall/floor/ceiling heads | Registers only |
| Typical Seattle range | $3,500–$6,000 single · $6,000–$15,000 multi | $8,000–$16,000 (heat pump on existing ducts) |
| Duct losses | None | 20–30% typical unsealed (ENERGY STAR) |
| Central filtration/IAQ | Per-head washable mesh | Media cabinets, UV — one mounting point |
| Install disruption | 3-inch penetrations, 1–3 days | Low on existing ducts; major if building new |
Ductless mini-splits
Choose ductless when…
The house has no usable ducts, rooms need independent control, or you're solving spaces incrementally (ADU, bonus room, upstairs first). Seattle's pre-war stock made this the region's standard retrofit — the plaster stays intact and each room finally holds its own temperature. Multi-zone ductless also posts the region's highest HSPF2 ratings, which matters for PSE gas-conversion eligibility (≥9.5 required) and SCL's top instant-discount tier. Townhomes, wall-heater condos, and mid-century baseboard homes all land here. Phased installs — one zone now, more later — are a normal ductless strategy in this market.
Central ducted system
Choose central when…
You own sound ductwork (test it — ~15% leakage is the WA code action threshold), prefer invisible delivery, or want central filtration for allergy/smoke reasons. Reusing good ducts is the cheapest per-room whole-home path there is. A ducted heat pump on sealed ducts also gives you one mounting point for media filtration and UV — the whole-house IAQ play that per-head mesh filters can't replicate. Suburban two-stories with tested ducts are the classic central-path profile. If your ducts test above the leakage threshold, seal first — the reclaimed capacity often changes the equipment sizing recommendation.
The Seattle-area numbers
Ductless mini-split (single zone)
$3,500 – $6,000
One outdoor unit + one indoor head — equipment, labor, electrical, permit
Sources: Seattle Mini Split Pros cost guide (2026) · Angi — ductless mini-split cost, Seattle WA (2026)
Ductless mini-split (multi-zone)
$6,000 – $15,000
One or more outdoor units serving 2–4+ rooms
Sources: Seattle Mini Split Pros cost guide (2026) · Angi — ductless mini-split cost, Seattle WA (2026)
Ducted heat pump installation
$8,000 – $16,000
All-electric heating + cooling using your existing ductwork
Sources: HVAC Project Cost — Seattle, WA (citing Angi 2026) (2026) · WattFax — 113 WA homeowner quotes (2026)
These are typical Seattle-area market ranges compiled from published cost guides (Angi, HomeGuide, and Seattle-area 2025–2026 cost studies) — market context, not a quote from Glendale Heating & Air Conditioning. Your home's size, equipment, ductwork, electrical, and permits change the number. National figures are marked; Seattle-area labor typically runs above national averages.
Questions homeowners ask about this choice
Which is more efficient?
Ductless starts ahead by skipping duct losses (20–30% in typical unsealed systems) and posting the highest HSPF2 ratings sold. But a tight, sealed duct system narrows the gap substantially — which is why the duct test comes before the verdict.
Can one house use both?
Very commonly: central for the original ducted footprint, heads for the addition, ADU, or stratified upstairs. Hybrid layouts are a Seattle staple, not a compromise.
What about the look of the heads?
It's the honest trade for skipping ducts. Placement above sightlines, floor consoles, and slim ceiling cassettes all soften it — but if visible equipment is a hard no and you have no ducts, price the compact-ducted hybrids (e.g. slim-duct cassettes) before committing either way.
Which path qualifies for more rebate money?
Both can — it depends on utility territory and what's being displaced. SCL instant discounts apply to qualifying ducted and ductless models by HSPF2 tier. PSE's largest rebates target gas conversions ($3,000–$4,000 ducted, ductless gas-conversions need ≥9.5 HSPF2). Electric-resistance homes qualify for PSE's electric-conversion path either way. The model and territory decide, not the distribution choice alone.
How do I know if my ducts are worth keeping?
A blower-door duct test with a leakage percentage — WA code uses ~15% as the action threshold on replacements. Below that with sound construction, central ducted is usually the cheaper whole-home path. Above it, sealing may recover enough capacity to stay central; if the ducts are crushed, disconnected, or routed through unconditioned space with no fix, ductless wins on economics and comfort. The test costs less than guessing wrong — and it's required on many replacement permits anyway.
Go deeper
The full ductless-vs-ducted decision guide
Related
Single vs multi-zone
Related
Ducted HP vs ductless multi
Take action
Ductless installation
How we know this
Duct-loss figures per ENERGY STAR; retrofit cost context per regional installer guidance; ranges from published Seattle-area studies (2026).
Reviewed by the Glendale Heating & Air Conditioning team · Last updated 2026-07-15
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