HVAC for pre-war Seattle homes: Craftsmans, Tudors, foursquares
Pre-1940 Seattle homes were built around radiators, gravity furnaces, or nothing — so comfort projects here are retrofits, not swaps. The standard modern answer is a ductless multi-zone heat pump (three-inch wall penetrations, plaster intact); the wildcard costs are electrical panels (60–100 amp services are common) and legacy oil equipment, which Seattle pays $2,000–$6,000 to retire. Balloon framing, minimal insulation by modern standards, and room-by-room temperature swings are the comfort baseline these systems are designed to fix. Nearly every pre-war conversion we run starts with a load calculation and a panel assessment before equipment is discussed.
The realities of this stock
- Usually no usable ductwork — retrofitting ducts through plaster and balloon framing is invasive and expensive
- Panels of 60–100 amps are common; electrification may need a panel upgrade
- Oil-furnace legacies are still out there — Seattle estimates 8,000–10,000 homes still heat with oil
Why these houses fight ductwork
Balloon framing, plaster-and-lath walls, and floor plans that predate forced air make duct retrofits invasive: regional installers put duct-building costs at $5,000–$15,000, and that's before patching the plaster. Where a dry basement runs under the main floor, short duct runs can serve the first story — our in-house sheet metal shop fabricates those custom runs — but whole-house ducting through finished walls rarely survives the estimate honestly.
That's why ductless became the pre-war standard: heads mount high on walls, line sets ride the exterior in paintable channel, and each room finally gets its own control — no small thing in houses famous for warm parlors and arctic bedrooms.
The oil-tank subplot
Seattle estimates 8,000–10,000 homes still heat with oil, and nearly all of them are this stock. The city calls oil its most expensive heat and pays real money to leave it — $2,000 at any income, up to $6,000 income-qualified, tank decommissioning included in scope. If your basement has a tank (or your yard has a mystery fill pipe), read the oil guide before any repair decision.
Do the electrical math early
Pre-war services of 60–100 amps are normal, and a multi-zone heat pump wants a dedicated circuit with headroom. Sometimes capacity exists; sometimes a panel upgrade joins the project (occasionally rebate-assisted for income-qualified households via WA HEAR). The point isn't that panels are scary — it's that an honest bid answers the panel question at estimate time, priced, instead of mid-install.
Freed radiator or baseboard circuits sometimes provide the headroom needed without a full panel swap — one of the quiet advantages of leaving legacy heat in place (unpowered) while ductless becomes primary. An NEC load calculation settles the question in minutes at the estimate visit.
Income-qualified households in Seattle should ask about WA HEAR and Office of Housing programs that can assist with panel work as part of an oil-to-heat-pump conversion — the Clean Heat program pairs with electrification scope, and panel upgrades are a common line item on pre-war bids.
What we actually recommend here
Primary fit
Ductless multi-zone heat pump
The standard pre-war retrofit: indoor heads need only a 3-inch wall penetration, so the plaster, trim, and floor plan stay intact — and each zone gets its own control. Mitsubishi H2i and Daikin wall units both fit this pattern.
$6,000 – $15,000 typical Seattle-area range (Seattle Mini Split Pros cost guide, 2026)
See the ductless lines we installAlternate
Ducted heat pump or furnace (basement-run ducts)
If your basement or crawl space allows duct runs without tearing walls open, central forced-air is still viable — and our in-house sheet metal shop fabricates custom ductwork for exactly these houses.
$8,000 – $16,000 typical Seattle-area range (HVAC Project Cost — Seattle, WA (citing Angi 2026), 2026)
Furnace & ducted optionsStill on oil? Seattle's Clean Heat rebate pays $2,000 (up to $6,000 income-qualified) to switch to a heat pump — and oil is Seattle's most expensive heat, so the savings math is strongest here.
Every Seattle home is different — this is honest general guidance, not a system spec. The right answer comes from a real in-home load calculation (Manual J), duct and electrical-panel inspection, which is exactly what our free estimate includes. 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 owners of these homes ask
Will heads and line sets ruin the period look?
Handled with care, no: heads above sightlines or floor consoles under windows, line sets routed on secondary facades in paint-matched channel. It's a design conversation we have at the estimate — these houses deserve installers who've worked them, and we've been in them since they were new.
Can I keep my radiators?
If they work and you love them, they can stay as backup or aesthetic — the ductless system simply becomes primary. Oil-fired boilers are the exception: Clean Heat requires retiring the oil plant, tank included, to collect the rebate.
What does a typical pre-war conversion cost?
Market ranges: single-zone $3,500–$6,000, multi-zone $6,000–$15,000 by zone count (published Seattle-area figures, not a quote); panel work extra where needed; minus $2,000–$6,000 Clean Heat on oil conversions. The estimate visit turns those ranges into your number. Oil conversions with tank decommissioning sit at the top of the range but also carry the largest rebate — net cost often lands below a non-oil multi-zone project.
How many zones does a typical Craftsman need?
Most whole-home conversions land at three to four zones: main living, bedrooms upstairs, and sometimes a basement or enclosed porch. Open first floors often share a head; the load calculation — not the room count — sets zone boundaries. Oversplitting into too many zones creates short-cycling on heads that can't load down far enough.
What about homes with partial ductwork in the basement?
Some pre-war homes have short basement duct runs serving only the main floor — our sheet metal shop can extend those runs or integrate a hybrid: ducted for the first story, ductless heads upstairs where snaking ducts through finished plaster isn't viable. The duct test and load calc per floor decide whether the hybrid saves money or whether full ductless is cleaner. Hybrid layouts are common on Craftsman first floors with finished upstairs bedrooms — you keep registers on the main level and add two or three heads above.
Ready for comfort you can count on?
Whether it's a furnace that quit on a cold morning or a whole new system, the Glendale team is ready. Honest pricing, expert work, and 87+ years behind every visit.
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