# How Much Does an Oil to Heat Pump Conversion Cost in Seattle?

> Oil to heat pump conversion cost in Seattle: a ducted heat pump budget plus oil tank decommissioning, minus Clean Heat rebates. See what moves both numbers.

URL: https://seattleheatpumpco.com/guide/oil-to-heat-pump-conversion-cost/

Updated: 2026-10-21

*An oil conversion is two budgets in one: the heat pump and the tank. Here is how each one is priced in Seattle, what pushes them up, and which rebates and grants come off the top.*

An oil to heat pump conversion in Seattle costs the heat pump plus the tank. A ducted heat pump on usable ducts typically runs about $6,700 to $20,000, and filling a clean oil tank in place adds about $700 to $3,000 plus a $184 Fire Department permit. Clean Heat then takes $2,000 off a qualifying system.

**Key takeaways**

- Heat pump side: about $6,700 to $20,000 for a ducted system on usable ducts.
- Tank side: about $700 to $3,000 to fill a clean tank in place, plus $184 per tank for the Fire Department permit.
- Tank removal, soil sampling and leak cleanup have no reliable published range; they are priced after a site visit.
- Seattle Clean Heat: $2,000 off a qualifying conversion, $4,000 more for moderate incomes, and free conversions for income-eligible households.

These are budgeting ranges for Seattle-area projects, not quotes. [The Seattle Heat Pump Company](https://seattleheatpumpco.com/) publishes them because oil conversions are where homeowners most often get one lump-sum number with no way to tell which half is doing the work. The Seattle Heat Pump Company plans and manages [oil to heat pump conversions](https://seattleheatpumpco.com/oil-to-heat-pump-conversion/) in Seattle and King County, with the heat pump installed by licensed and insured contractors and the tank handled by ICC-certified decommissioners.

## The two budgets in an oil conversion

There is no separate price band for an oil conversion, and that is deliberate. The cost is the heat pump installation plus the tank work, and each half has its own drivers. Treating them separately is the clearest way to read a quote.

| Part of the job | Typical range | What decides where you land |
|---|---|---|
| Ducted heat pump installation | $6,700–$20,000 | Size, efficiency tier, air handler, duct condition, line set and access |
| Oil tank fill in place, clean site | $700–$3,000 | Tank size, access to the fill pipe, how much oil and sludge remain |
| Seattle Fire Department permit 6103 | $184 per tank | Fixed fee, issued to the decommissioner |
| Electrical panel upgrade, 100 to 200 amps | $1,333–$4,500 | Only if the panel cannot carry the new heat pump and backup heat |
| Air handler replacement | $1,500–$4,200 | National figures; usually part of the heat pump price on an oil conversion |
| Tank removal | Priced after a site visit | Burial depth, tank size, access, what sits on top, restoration |
| Soil sampling | Priced separately | Number of samples, lab turnaround, whether contamination is suspected |
| Leak cleanup | Open-ended | Extent of contamination; can run well past the rest of the project |

National cost publishers put a central ducted heat pump at about $5,000 to $15,000 (Fixr), and the Bonneville Power Administration's regional figure for high-performance ducted retrofits and conversions averages about $17,000. The Seattle range spans that evidence. The [installation cost guide](https://seattleheatpumpco.com/guide/heat-pump-installation-cost-seattle/) covers the heat pump drivers in depth; this page focuses on what is different when oil is the starting point.

## The heat pump side: what changes when oil goes

An oil conversion is never a simple equipment swap. The oil furnace is leaving, which changes the indoor equipment, the electrical load and sometimes the venting.

### An air handler where the oil furnace stood

Most oil conversions replace the oil furnace with an electric [air handler](https://seattleheatpumpco.com/air-handler-replacement/), which holds the heat pump's indoor coil and the blower that moves air through the ducts. The alternative, a heat pump coil on a gas furnace, only makes sense when gas is already at the house and you plan to keep it, which is unusual for an oil-heated home and does not fit the Clean Heat program's purpose of moving homes off fossil fuel heat.

An air handler usually includes electric backup heat strips for the coldest hours. Their size should come from the [load calculation](https://seattleheatpumpco.com/guide/heat-pump-sizing-manual-j/), and Seattle's energy code requires [backup heat controls](https://seattleheatpumpco.com/guide/heat-pump-backup-heat-settings/) that keep them off above 40°F, with the lockout set at 35°F or lower at final inspection. That keeps backup heat from quietly running up the bill.

### Ducts from the oil era

Many oil-heated Seattle houses are older; about 22.8% of the city's homes were built before 1940, according to Census data. A house that age may have ducts that were added or rebuilt over decades, or the large round ducts of an early gravity furnace. There is no local data on how many of those duct systems are still usable, so the answer comes from measuring yours.

A heat pump moves more air than an oil furnace to deliver the same heat, because its [supply air is cooler](https://seattleheatpumpco.com/guide/how-a-ducted-heat-pump-works/). A static pressure test shows whether the ducts can carry that airflow, need an added return or sealing, or need replacement. Whole-house duct replacement runs about $1,400 to $5,600 in HomeGuide's national figures, with Fixr's range running from about $1,900 to about $17,100 for complex installs. The [existing ductwork page](https://seattleheatpumpco.com/heat-pump-existing-ductwork/) explains the measurements, and [heat pumps for older homes](https://seattleheatpumpco.com/heat-pump-older-homes/) covers the wider set of issues in older houses.

### Electrical capacity

An oil furnace draws very little electricity: a burner motor, an igniter and a blower. A heat pump and its backup strips draw much more. Every conversion needs a new dedicated circuit and an outdoor disconnect. Whether the panel can carry them depends on its size, what else runs on it, and how much backup heat the design includes. There is no reliable local data on how many older Seattle houses still have 60 or 100 amp service, so this is a measured item, not an assumption. When a 100 to 200 amp upgrade is needed, Seattle-area projects typically budget about $1,333 to $4,500. The [panel guide](https://seattleheatpumpco.com/guide/heat-pump-electrical-panel-requirements/) covers the options, including sizing backup heat to avoid an upgrade where the load allows.

### Removing the old furnace, the flue and what is wrapped around it

The oil furnace, burner and oil lines come out as part of the conversion. Two things can add scope. First, if a gas or oil water heater shared the chimney with the furnace, removing the furnace changes how that chimney drafts, and the water heater's venting needs a look. Second, older furnaces and ducts can carry asbestos insulation. The Puget Sound Clean Air Agency requires an asbestos survey before renovation work, though an owner-occupant of a single-family house may do their own survey. If asbestos is found, abatement becomes its own line item and adds time.

## The tank side: fill in place, remove, or test

Seattle Fire Code requires a heating oil tank that has been out of service for a year or more to be decommissioned. The work must be done by, or directly supervised by, someone certified by the International Code Council as a tank decommissioner, under Seattle Fire Department permit 6103, separate from the heat pump's [refrigeration and electrical permits](https://seattleheatpumpco.com/guide/seattle-heat-pump-permit/). The permit is issued to the decommissioner, work cannot start until the application is stamped "Approved to Proceed," and a decommissioning report goes to the Fire Department within 30 days. Keep a copy of the stamped permit and report, because they matter when the house is sold.

Fire Department records show the paths homeowners take. Of the 6,914 residential decommissioning permits issued since 2021, about 60% were filled in place and about 24% were removals, with the rest awaiting a completed report.

### Filling in place: the $700 to $3,000 range

Filling in place means pumping out the remaining oil and sludge, cleaning the tank's interior, filling it with an inert solid such as sand, concrete slurry or foam, cutting and capping the fill and vent pipes, and filing the report. On a clean site, it typically runs about $700 to $3,000 plus the $184 permit. Tank size, how much residual oil is left and how easy the fill pipe is to reach move the number within that range.

One practical note: stop automatic oil deliveries once the conversion is scheduled. Oil left in the tank is pumped out as part of the work, and a fresh delivery right before decommissioning is money spent on oil you will not burn.

### Removal: what drives the price

Removal costs more than filling in place, but there is no reliable published Seattle range for it, so it is priced after a site visit. The drivers are physical:

- how deep the tank is buried and how large it is
- what sits on top of it: lawn, garden, a driveway, a patio or a deck
- how close it is to the house, a property line or utilities
- whether equipment can reach it or the dig is by hand
- hauling and disposal of the tank
- backfill and restoration of the surface

Removal also lets someone see and sample the soil directly. The Fire Department says tanks suspected of leaking should be removed rather than filled in place, and notes that a tank abandoned in place now may need to be removed later at additional cost. For many clean tanks, though, filling in place is the common and code-compliant choice. The [oil tank decommissioning](https://seattleheatpumpco.com/oil-tank-decommissioning/) page covers how that decision is made.

### Soil sampling

The Seattle Fire Code does not require soil samples for either method. Sampling is a choice, often made before a sale, at a buyer's or lender's request, or when the tank's history is unknown. Its cost depends on how many samples are taken, where, and how fast the lab needs to turn them around. For a sense of scale only, Oregon's Department of Environmental Quality cites about $200 to $300 for a soil test; that is an out-of-state official figure, not a Seattle price.

### If a leak turns up

This is the part no one can price in advance. The City of Seattle says cleanup of a leaking residential tank "can exceed $10,000," and Washington's Pollution Liability Insurance Agency says most completed cleanups exceed $60,000. Those are not ranges; they are warnings that a leak turns a conversion into an environmental project.

The state's no-cost heating oil insurance no longer covers new claims: the policy expired June 30, 2025. The successor is PLIA's Heating Oil Loan and Grant program, described below. If you suspect a leak, report it within 24 hours to 1-800-OILS-911 and stop oil deliveries, as the City of Seattle advises.

## Incentives that change the math

Oil conversions have the richest incentive stack of any heat pump project in Seattle. All amounts are; confirm the current terms before signing, because several require a participating contractor or pre-approval.

| Program | Amount | Who it applies to |
|---|---|---|
| Seattle Clean Heat base rebate | $2,000 off the invoice | Oil-heated Seattle homes, qualifying Mitsubishi Electric heat pump, participating contractor, tank decommissioned to Fire Department rules |
| Seattle Clean Heat moderate-income bonus | $4,000 more | Households at 81% to 150% of area median income, installs completed within the program's current funding period |
| Office of Housing HomeWise | Free conversion | Income-eligible Seattle households heating with oil |
| Seattle City Light contractor discount | $300 or $600 | City Light customers, qualifying equipment by efficiency tier, one system per home |
| PLIA Heating Oil Loan and Grant | Up to $75,000 per project | Property owners with heating oil tanks; not income-limited; PLIA must approve before work starts |
| Federal 25C tax credit | Ended | Not available for equipment placed in service after December 31, 2025 |

The Clean Heat rebate only works on qualifying Mitsubishi Electric equipment installed by a participating contractor; the contractors who carry out our projects can offer it on qualifying systems. The $4,000 bonus is funded through Washington's state home electrification rebate money, which is how that funding reaches Seattle homeowners; the separate federal IRA home energy rebates had not launched in Washington.

PLIA's program is the one that most often gets forfeited by accident. It covers leak cleanup and associated tank removal through grants, and offers a loan that can cover a heat conversion or decommissioning in place. It requires PLIA's approval before any work starts and does not reimburse completed work, so decommissioning first and applying later loses it. Applications open in windows; check PLIA's site for the current dates. The equipment tiers behind the City Light discount are explained in the [ratings guide](https://seattleheatpumpco.com/guide/seer2-hspf2-ratings-explained/). The [PLIA grant window post](https://seattleheatpumpco.com/blog/plia-heating-oil-grant-window/) has the details, and the [rebate guide](https://seattleheatpumpco.com/guide/heat-pump-rebates-seattle/) covers the full stack.

## Three example budgets

These are illustrative combinations of the published ranges, not quotes for any real house.

| Example | Heat pump side | Tank side | Incentives | Budget picture |
|---|---|---|---|---|
| 1950s house, oil furnace, ducts test fine, buried tank in the side yard, no signs of a leak | Air handler replaces furnace, new outdoor unit | Fill in place $700–$3,000 plus $184 permit | Clean Heat $2,000; City Light $300 or $600 | Installation range plus the tank, minus about $2,300 to $2,600 |
| 1920s house, undersized return, 100 amp panel, moderate income | Air handler, added return, panel upgrade $1,333–$4,500 | Fill in place plus permit | Clean Heat $2,000 plus $4,000 bonus | Installation range plus panel and duct work and the tank, minus about $6,000 or more |
| House being sold, buyer asks for removal and soil samples | Air handler and outdoor unit | Removal and sampling, priced after a site visit | Clean Heat $2,000; PLIA if contamination is found and PLIA approved the work first | Installation range plus a removal quote; open-ended if a leak turns up |

The [typical oil conversion walkthrough](https://seattleheatpumpco.com/blog/typical-oil-to-heat-pump-conversion/) shows how a project like the first example moves from assessment to final inspection.

## The order of operations matters

Sequencing affects both the cost and the incentives:

1. **Check PLIA first** if there is any chance you will want its funding. Applying after the tank work is done forfeits it.
2. **Get the [assessment](https://seattleheatpumpco.com/tools/heat-pump-assessment/)**: load calculation, duct test, panel check, tank location and outdoor-unit siting that meets the [noise rules](https://seattleheatpumpco.com/guide/seattle-heat-pump-noise-ordinance/).
3. **Confirm Clean Heat eligibility** and that the quoted equipment qualifies before signing, using the [quote comparison checklist](https://seattleheatpumpco.com/guide/how-to-compare-heat-pump-quotes/).
4. **Install the heat pump**, so the house is never without heat.
5. **Decommission the tank** under the Fire Department permit once the furnace is off, and keep the report.

Seattle aims to move every oil-heated home off oil by 2030. The city estimates roughly 7,000 to 10,000 oil-heated homes remain, down from about 18,000 in 2018, and Fire Department records show about 1,000 to 1,400 residential decommissioning permits a year since 2021. Census data puts the largest numbers of oil-heated households in [West Seattle](https://seattleheatpumpco.com/service-areas/west-seattle/) and [Northeast Seattle](https://seattleheatpumpco.com/service-areas/northeast-seattle/).

## Outside Seattle city limits

The Clean Heat rebate and the HomeWise program are for Seattle homes only. In the suburbs, the heat pump side prices the same way, but the tank rules and incentives differ. Shoreline Fire Department issues residential tank decommissioning permits for Shoreline and Lake Forest Park, and Bellevue uses its own permit process with an ICC-certified decommissioner. Burien has the highest share of oil-heated homes among the suburbs in Census data, about 9%, and its tank permit process should be confirmed locally before work is scheduled. PLIA's program is statewide. See [Burien](https://seattleheatpumpco.com/service-areas/burien/) and [Shoreline and Lake Forest Park](https://seattleheatpumpco.com/service-areas/shoreline-lake-forest-park/) for local details.

## Is converting worth it?

There is no official heating oil price series for Washington, so a precise savings figure is not possible from public data. What is clear is that oil heat keeps a tank in the ground as a liability, the state insurance that once backed it is gone, and the city's incentives are unusually generous while current funding lasts. The [heat pump vs oil furnace guide](https://seattleheatpumpco.com/guide/heat-pump-vs-oil-furnace/) works through the comparison, and the [cost estimator](https://seattleheatpumpco.com/tools/heat-pump-cost-estimator/) gives a heat pump range for your house. When you are ready for both halves of the number, call or send a few details about the house, the furnace and where the tank sits.

## Questions

### Do I have to remove the oil tank when I convert to a heat pump?

No. Seattle Fire Department rules require a tank that has been out of service for a year to be decommissioned, and both removal and filling in place are code-compliant. The department does say a tank suspected of leaking should be removed. Filling a clean tank in place is usually the less expensive path, at about $700 to $3,000 plus the $184 permit.

### Is soil testing required when an oil tank is decommissioned in Seattle?

The Seattle Fire Code does not require soil samples for either removal or filling in place. Homeowners often choose sampling anyway, before a sale, when a buyer or lender asks, or when there are signs of a leak. Sampling is priced separately, and what it costs depends on how many samples are taken and how quickly results are needed.

### Can I still use the PLIA grant if my tank is already decommissioned?

Generally not. PLIA's Heating Oil Loan and Grant program must approve work before it starts and does not reimburse work already completed. If there is any chance you will want PLIA funding for a leak cleanup or the conversion loan, apply first. PLIA takes applications in a limited window each year, usually in late fall, so check PLIA's site for the current dates.