Wood-burning sauna stoves in Washington and Oregon: permits, burn bans and clearances

Key facts

• Washington burn bans: WAC 173-433-150 bars operating any solid fuel burning device during a Stage 1 ban when the home has another adequate heat source, unless it is an EPA-certified woodstove, an Oregon DEQ Phase 2 stove or a nonaffected pellet stove. Its table lists "EPA Exempted Device" as NO in Stage 1 and Stage 2.
• Washington sales: WAC 173-433-100(3) bars selling a solid fuel burning device unless certified and labeled, at 2.5 g/hr for catalytic woodstoves and 4.5 g/hr for all other solid fuel burning devices. The definition (WAC 173-433-030) covers devices used "for aesthetic or space-heating purposes."
• Oregon sales: ORS 468A.465 bars selling a new solid fuel burning device unless DEQ certifies it. ORS 468A.485 defines the term to include devices burning wood "for aesthetic, space-heating or water-heating purposes in a private residential structure or a commercial establishment."
• Permits: Portland requires a mechanical permit to install "any solid fuel burning appliance" and a factory-built chimney. Seattle lists solid-fuel stoves among its residential mechanical permit types.
• Install: solid-fuel room heaters must be tested to UL 1482 and installed per their listing (IRC M1410.1). Factory-built chimneys go in per the maker's instructions (R1005.1).

Sources: WAC 173-433-150, WAC 173-433-100, WAC 173-433-030, Washington Ecology wood stove information, Southwest Clean Air Agency certified devices, ORS 468A.465, ORS 468A.485, Portland wood stove permits, Seattle SDCI mechanical permit criteria, and the 2021 Seattle Residential Code Chapter 10 and Chapter 14, which carry the IRC sections cited here.

Why sauna stoves fall into a gap

Federal wood stove rules are built around home heaters. A sauna stove heats a small hot room to sauna temperature, so makers often argue it is a different category. Lamppa, which builds the Kuuma stove in Minnesota, states that EPA has determined the 2015 Residential Wood Heater Rule "does not apply to Kuuma sauna stoves as manufactured and intended for sauna hot-room use," and that the stoves are therefore not EPA-certified. Lamppa also states the stoves are listed to UL 1482 (the safety standard for solid-fuel room heaters) by PFS-TECO.

That federal answer does not settle the state question. Washington and Oregon write their own rules around the broader term "solid fuel burning device," and both definitions reach past whole-house heating to include aesthetic use. Neither rule we read mentions saunas. So a stove can be perfectly legal under federal rules and safety-listed, yet still sit in a gray zone under state air rules.

Washington: the burn ban problem

This is the part most buyers miss. Washington's burn ban rule applies to "any solid fuel burning device" in a residence that has another adequate source of heat. A backyard sauna almost always belongs to a house with a furnace or heat pump, so the exception for wood-only homes will not help.

Our reading: an EPA-exempt or uncertified sauna stove has to sit cold through every Stage 1 and Stage 2 ban. If a ban starts while your stove is lit, the rule says to stop adding fuel. Smoke still visible three hours after a ban is called counts as evidence of a violation. Puget Sound Clean Air, Southwest Clean Air and other local agencies call bans for their areas. Our Washington burn ban guide explains Stage 1 and Stage 2 and how to check status.

Washington calls these bans when air quality is impaired, and that can happen in the same cold months when a sauna is most tempting. If you want a sauna you can use any night of the year in western Washington, that is a practical point in favor of an electric heater. Our Washington sauna permits and electrical guide covers that route.

Washington: can the stove even be sold to you?

WAC 173-433-100(3) says a person must not advertise, sell, exchange or give away a solid fuel burning device in Washington unless it is certified and labeled and meets the 2.5 or 4.5 g/hr limits. Southwest Clean Air's summary goes further: "Even devices that are exempt from EPA certification must meet Washington standards." Ecology's own list of certified device categories includes wood stoves, pellet stoves, fireplaces, masonry heaters, hydronic heaters and furnaces. We did not find sauna stoves addressed anywhere.

We are not going to tell you a given stove is illegal in Washington, because the rule does not name saunas and we found no agency ruling either way. What we would do before ordering: ask the maker to state in writing whether the model meets WAC 173-433-100 or why it does not apply, and ask Ecology's wood stove coordinator or your local clean air agency. Keep the answers with your permit file.

Oregon: certification, red days and Portland permits

• Sales: ORS 468A.465 bars selling a new solid fuel burning device in Oregon unless DEQ certifies it. The definition in ORS 468A.485 covers wood burned "for aesthetic, space-heating or water-heating purposes in a private residential structure or a commercial establishment," with listed exclusions such as certain fireplaces, masonry heaters and central furnaces. Sauna stoves are not among the listed exclusions, and the law does not say whether a detached sauna is part of a "private residential structure." Ask DEQ.
• Installation in Portland: Portland says state law requires a permit, inspection and approval to install a wood stove, insert or chimney, and that to legally install a wood stove "it must be certified." Its permit table lists a mechanical permit for "any solid fuel burning appliance" and for a factory-built or metal chimney, plus an electrical permit if a fan or wiring is involved. Portland's mechanical permit application lists $94 for a wood or pellet stove, $38 for a chimney or flue, a $167 minimum permit fee and a 12% state surcharge.
• Homeowner work: Portland lets the recorded property owner (not an LLC) do their own mechanical work under a permit.
• Burn days: Multnomah County bars wood burning devices on red days from October 1 to March 1, and LRAPA and Southwest Clean Air run their own programs. See our Portland, Eugene and Vancouver burn restrictions guide.

Clearances: follow the listing, and here is what one looks like

IRC M1410.1 requires solid-fuel room heaters to be tested to UL 1482 and installed per their listing and the manufacturer's instructions. M1410.2 calls for a noncombustible floor extending 18 inches beyond the appliance on all sides, with an exception that lets listed heaters use the floor protection their instructions specify. In practice the stove's manual sets your numbers. As a real example, Lamppa publishes these for the Kuuma:

Lamppa adds that a wall shield should start 4 inches off the floor, reach 52 inches high and extend 8 inches past the stove on each side; that ceilings 8 feet or lower need a 3 by 5 foot ceiling shield with a 2 inch air gap; and that the floor needs a noncombustible ember-protective surface. It recommends a 4 inch dedicated outside-air vent near the stove. These are one maker's figures for one stove. Do not apply them to a different model.

Shrinking clearances with shields is how most small PNW saunas fit a wood stove at all. A 38 inch side clearance in a 6 by 7 foot room leaves little bench space, so plan the shielding before you frame.

Chimneys

• Height: masonry chimneys must extend at least 3 feet above where they pass through the roof and at least 2 feet higher than any part of a building within 10 feet (R1003.9). Factory-built chimneys are terminated per their instructions (R1005.1).
• Type: in dwelling units with solid-fuel appliances, factory-built chimneys must meet UL 103 Type HT and be marked accordingly (R1005.3). A detached sauna may not be a dwelling unit, so ask your building official which rule applies.
• Components: Lamppa specifies a 6 inch flue throughout for the Kuuma, single or double wall pipe to the ceiling, then UL-listed Class A chimney through the roof, all chimney parts from one manufacturer, and an open-style cap.
• Roof framing: where a factory-built chimney is supported by joists or rafters, those members must be designed for the load (R1005.5).

Wet-climate note: a chimney is another roof penetration on a building that already fights rain and steam. Flash it with the chimney maker's parts for your roof pitch. Our rainy-climate sauna guide covers roofs and foundations.

Before you buy a wood sauna stove in Washington or Oregon

1. Ask the maker for its UL 1482 (or other) safety listing and its EPA, Washington and Oregon emissions status, in writing.
2. Call your building department about the mechanical permit and whether a detached sauna counts as a dwelling unit for the chimney rule.
3. Look up your clean air agency's burn ban or curtailment rules and decide whether you can live with the sauna being unusable on ban days.
4. Lay out clearances from the stove manual, with shields, before framing the room.
5. Check your homeowner's insurance, which may ask about solid-fuel appliances.

Still deciding between wood and electric? Our guides to sauna heater breaker and wire size and Oregon sauna permits and electrical cover the electric side.

Related guides

• How many sauna stones do I need, and when to replace them
• Washington burn bans and fire pits
• Fire pit burn restrictions in Portland, Eugene and Vancouver
• Backyard sauna permits and electrical in Washington
• Backyard sauna permits and electrical in Oregon and Portland
• Outdoor saunas in rainy climates

Frequently asked questions

Do I need a permit for a wood-burning sauna stove in Washington or Oregon?

Expect to. Portland says state law requires a permit, inspection and approval to install a wood stove or chimney, and its mechanical permit covers "any solid fuel burning appliance" plus factory-built chimneys. Seattle lists solid-fuel stoves among its residential mechanical permit types. Other cities and counties set their own process, so call your building department before you buy the stove.

Can I use a wood sauna stove during a Washington burn ban?

Usually not. Under WAC 173-433-150, during a Stage 1 burn ban you must not operate a solid fuel burning device if the home has another adequate heat source, unless it is an EPA-certified woodstove, a DEQ Phase 2 stove or a qualifying pellet stove. The rule's own table marks EPA-exempted devices "NO" in Stage 1. In Stage 2, no wood device may be used. Most sauna stoves are not EPA-certified.

Is a wood-burning sauna stove EPA certified?

Often not, because it is not a home heater. Lamppa, maker of the Kuuma sauna stove, states that EPA has determined the 2015 residential wood heater rule does not apply to Kuuma sauna stoves used for sauna hot rooms, so they are not EPA-certified. That matters in Washington, where burn bans and sales rules are written around certification.

Can a wood sauna stove be sold in Washington if it is not EPA certified?

It is unclear, so get it in writing. WAC 173-433-100 bars selling a solid fuel burning device in Washington unless it is certified and meets 2.5 g/hr (catalytic) or 4.5 g/hr (other devices), and the definition includes devices used for aesthetic or space-heating purposes. Southwest Clean Air says even EPA-exempt devices must meet Washington standards. We found no written sauna stove exemption. Ask the maker and Ecology before you order.

How far does a wood sauna stove need to be from the walls?

Whatever its listing and manual say. Codes require listed room heaters to be installed per their listing. As one example, Lamppa lists 48 inches in front of a Kuuma stove, 38 inches to the side and 28 inches to the back with no shielding, and as little as 7 inches side and 8 inches back with heat shields on both the stove and the wall. Other stoves differ.

How high does a sauna chimney need to be?

For masonry chimneys, the residential code requires at least 3 feet above where it passes through the roof and 2 feet higher than any part of a building within 10 feet (R1003.9). Factory-built metal chimneys, the usual choice for a sauna, must be installed and terminated per the chimney maker's instructions (R1005.1). In dwelling units, solid-fuel chimneys must be UL 103 Type HT (R1005.3).

Can I use a wood sauna stove on a Multnomah County red day?

Not unless you are exempt. Multnomah County bars operating a wood burning device on a red air quality day from October 1 to March 1, and a sauna stove burns wood. LRAPA in Eugene and Springfield and Southwest Clean Air in Clark County run their own curtailment programs. See our Oregon burn restrictions guide for the details and exemptions.

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