Seattle is one of the last big West Coast markets where the oil comparison in this guide's title is a live question rather than a formality. The city's prewar neighborhoods, the foursquares of Wallingford and Ravenna, the craftsman blocks of Ballard and West Seattle, the boxes climbing Queen Anne, were built in oil's era, and a meaningful number of those basements still hold an oil furnace with a tank buried somewhere under the yard. Seattle City Light knows it, which is why the utility's rebate ladder tops out at $2,000 for exactly one measure: the oil-to-heat-pump conversion. Around the oil stock sits the rest of the city's heating inheritance, electric furnaces and baseboards, gas furnaces across the newer rings, and aging heat pumps from the first wave of remodels. This guide runs the conversion arithmetic against each.
The Ledger in One Table
| Existing heat | Case for a heat pump | Strength |
|---|---|---|
| Heating oil | Truck-priced fuel loses to metered kilowatt hours; tank retires; $2,000 City Light line | Strongest |
| Electric furnace / baseboard | Same meter, a half to a third the consumption | Strongest |
| Aging heat pump | Modern variable-speed machine beats it both seasons | Strong |
| Natural gas | Closest race; cooling and the rebate settle it | Honest maybe |
Oil: The Fuel the City Pays You to Leave
The oil case has four layers here, one more than most markets. First, the fuel bill: oil arrives by truck at prices that swing season to season, while a heat pump moves two to three units of heat per unit of electricity purchased at rates that move slowly, and across a damp Seattle heating season the operating gap is wide and persistent. Second, the equipment: most surviving oil furnaces are decades old and running on borrowed time. Third, the tank: an aging buried tank is a liability sitting in the yard, and a conversion retires it, with decommissioning priced as a named line, per our installation cost guide. Fourth, and unique to this city, the utility's thumb on the scale: Seattle City Light pays $2,000, the top of its entire rebate ladder, for the oil conversion specifically, per our City Light guide. No other fuel on this page pays you four ways for leaving it.
Electric Resistance: The Multiplication That Never Misses
The city's mid-century stock and its apartment conversions lean on electric furnaces and baseboards, machines that turn one unit of electricity into one unit of warmth at full price. A heat pump on the same meter moves two to three units per unit purchased, so the heating share of the bill shrinks toward a half or a third with no fuel forecast in the calculation and no new utility relationship required. Where the house has ducts, the electric-furnace changeout is the simplest project in the book; where it has baseboards and no ducts, the conversion is a ductless project, which this city executes as routinely as anywhere in the country, and the same heads deliver the first real cooling the house has ever had.
The Honest Gas Paragraph
A household with a functioning gas furnace faces the closest race in this guide, and deserves it stated plainly. Gas is cheap heat, the winters are mild, and displacing a mid-life furnace rarely pays on fuel savings alone. What moves the 2026 verdict is the rest of the ledger: the utility rebate layer trims the conversion, per our rebates guide; the PNW summer has stopped being optional to cool, and the heat pump buys cooling and heating in one machine while the furnace buys only one of them; and at equipment failure, when the replacement dollar must be spent anyway, the marginal cost of choosing the heat pump is small. Dual fuel remains a legitimate configuration a good contractor prices without being asked. What no honest bidder does is promise a gas household dramatic heating savings; a bid that does has failed the first test in our contractor guide.
The Aging First-Wave Heat Pump
Seattle's early adopters put heat pumps in years ago, and the first wave is aging out. Against a modern variable-speed machine, an old single-stage unit loses on both seasons: it cannot modulate through the long forty-degree stretches that are this climate's real winter, so it cycles instead of cruising, and its cooling is a blunt instrument in the summers that now arrive in earnest. The replacement math is undramatic but reliable, and the rebate ladder helps, because the measures that pay best are the variable-speed tiers the replacement should be anyway.
The Climate That Flatters the Machine
Every comparison above leans on the same background fact: Puget Sound is close to ideal heat pump country. Design nights sit around the high twenties, mild enough that modern equipment retains most of its rated capacity without cold-climate premiums; the season's real signature is months of damp air in the forties, which rewards machines that modulate low and run steadily; and the dry, bright summers give the same machine a second job the housing stock never planned for. A heat pump here is not a compromise being defended; it is the tool the climate was waiting for, which is why the math on this page runs downhill.
Reading the First Year Correctly
Judge a conversion by shape, not by a single statement. The oil convert sees the delivery line vanish and a modest rise in winter electricity. The electric-resistance convert sees the same warmth cheaper immediately. The gas convert at failure time sees a similar winter and a far better summer. The discipline that makes all three legible is one ledger: last year's total heating and cooling spend, every fuel and every truck, next to this year's, read whole year against whole year. A single January bill misleads in a climate where the savings are spread thin and wide across ten mild months.
Renters, Landlords, and the Split Incentive
The city's worst heating economics disproportionately serve tenants: baseboard units billed to renters through the wet season, box fans dragged out for the hot weeks. The tenant pays the bill; the owner owns the fix; and the arithmetic reads identically for both, with only the beneficiary line changing. The owner's case needs no charity: the resistance conversion is among the strongest math on this page, the rebate layer trims it, and a unit with real heat and real cooling rents better in every season. A tenant's cheapest move is forwarding this page to whoever holds the deed.
The Short Version
Oil loses four ways in Seattle: on the fuel, on the dying furnace, on the tank in the yard, and against the $2,000 City Light line built specifically to end it. Electric resistance loses on a single bill's multiplication. Aging heat pumps lose both seasons to a modern variable-speed machine. Functioning gas is the honest race, and the cooling line plus the rebate layer settles it more often each year. The math carries every case from Ballard to Columbia City, and the machine that wins it was practically designed for this climate.
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