What is Harvia M3 Wood Stove?
Harvia M3 Wood Stove is a floor-standing heater from Harvia with 16.5 kW output and 66 lbs stone capacity.
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Harvia M3 Wood Stove
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Harvia M3 Wood Stove sauna heater specs and 3D room planner
Use this manual-checked Harvia M3 Wood Stove product page to compare wood output, adjusted room volume, clearances, chimney path, stones, floor protection, and manual install checks before you open the sauna in the designer.
Harvia M3 Wood Stove is a floor-standing heater from Harvia for 212-459 cu ft adjusted sauna rooms. Key planning facts: 16.5 kW output, 66 lbs stone capacity, and 78.7" minimum finished ceiling guidance, plus T600 chimney path, 115 mm flue connection, hearth/floor protection, combustion air, and local fire-code review.
Design with Harvia M3 Wood Stove Buy in North America at Sauna Marketplace
Quick answers
What sauna room size fits Harvia M3 Wood Stove?
The published adjusted room-volume range is 212-459 cu ft. Add glass, tile, stone, brick, concrete, or log exposure before choosing the final kW row.
What clearances does Harvia M3 Wood Stove need?
Unshielded M3 planning uses 9.84" side clearance, 11.8" rear clearance, 11.8" front clearance, and a 78.7" minimum finished ceiling check. With the Harvia WL400/WL450 protective sheath selected and installed per Harvia, side/rear combustible clearances reduce to 50 mm (1.97") while front clearance stays 300 mm (11.8").
What chimney does Harvia M3 Wood Stove need?
Plan a T600 chimney path with 115 mm stove connection, the selected WHP chimney parts or AHJ-approved equivalent, lead-through protection, and local fire-code review.
Where should I start with Harvia M3 Wood Stove?
Use the 3D designer to validate the room, benches, openings, combustible clearances, chimney lead-through, guard rail, hearth protection, and material schedule before purchase.
Harvia M3 Wood Stove size and clearance table
| Variant | Power | Room volume | Dimensions | Rocks | Side/back | Front | Minimum ceiling | Chimney / install |
|---|---|---|---|---|---|---|---|---|
| M3WKM3 / M16 | 16.5 kW | 212-459 cu ft | 15.3" W x 17.7" D x 27.9" H | 66.2 lb | 9.84" | 11.8" | 78.7" | Manual wood stove; chimney and hearth package by installer |
| M3 SLWKM3SL | 16.5 kW | 212-459 cu ft | 15.3" W x 25.2" D x 28.1" H | 66.2 lb | 9.84" | 11.8" | 78.7" | Manual wood stove; chimney and hearth package by installer |
Best fit
- 16.5 kW Harvia heater family for 212-459 cu ft adjusted hot rooms.
- Floor-standing layouts where the heater footprint, front clearance, and bench approach are planned before ordering.
- 66 lbs stone capacity with chimney, hearth, heat-shield, and combustion-air planning handled before ordering.
- Rooms that can meet the 78.7" minimum finished ceiling check for the selected size row.
- Floor structure, non-combustible base, stove guard rail, chimney route, and roof lead-through should be resolved with the full room layout.
Designer checks
- Size the room by adjusted volume, including the 3.94 cu ft per sq ft (1.2 m3 per 1 m2) for glass, stone, tile, brick, concrete, or similar cold surfaces rule where it applies.
- Validate side/back clearance 9.84", front clearance 11.8", and bench setback before finalizing benches.
- Check the 78.7" minimum finished ceiling against the room height.
- Carry chimney kit/extensions/damper, lead-through, hearth protection, heat shields, ash handling, and local fire-code review into the material schedule.
- Align the WHP chimney and roof lead-through to the CAD top flue collar, not to the center of the rectangular heater footprint.
- Use the WL400/WL450 protective sheath toggle only when that Harvia accessory is part of the package; it reduces side/rear combustible clearances to 50 mm (1.97") but does not reduce the 300 mm (11.8") front clearance.
- Use the manual stone, fuel, first-heating, and ash-box instructions as operating notes, not just visual product copy.
Package notes
- Harvia M3 WKM3 wood stove body
- 66 lb; Harvia M3 Sauna Stones
- Installation and operation manual
- Harvia M3 Sauna Stones
- Harvia WHP1500 Stainless Steel Chimney Kit for M3
Manual-backed facts
Source
Harvia M3 WKM3 product specs, SaunaMarketplace data sheet, wood stove manual, WL400/WL450 safety drawing, and stove CAD archive
source: Harvia M3 wood-burning stove product specs, manual, safety drawing, and stove CAD archive (WKM3/M16 public Harvia specs and SaunaMarketplace-attached Harvia WKM3 data sheet; Pk CE/VTT wood-stove manual Y05-0109-1 0925; M3 safety drawing; WL400/WL450 protective sheath safety distances/manual/images only; WHP chimney manual; SAT-derived protected WKM3 GLB; checked June 9, 2026)
Mounting
Floor-standing
Floor-standing sizes use their own body height and top clearance.
Model numbers
WKM3 / M16 / WKM3SL
Useful when the store name and manual model number are not identical.
Room volume range
212-459 cu ft
Use adjusted sauna volume after cold surfaces, not just geometric room volume.
Body weight
97.5-99.2 lb
Listed body weight before stones; verify shipping weight with the final SKU.
Cold-surface adder
3.94 cu ft per sq ft (1.2 m3 per 1 m2) for glass, stone, tile, brick, concrete, or similar cold surfaces
The calculator applies the brand-family coefficient before selecting a heater size.
Minimum finished ceiling
78.7"
Computed from body height, floor clearance, top clearance, and the manual minimum room height.
Maximum room height
Not listed for these sizes
Verify with the selected manual when designing unusually tall rooms.
Electrical/control
Wood-burning; no electric heater circuit; Manual wood stove; chimney and hearth package by installer
Use the selected kW row and SKU when matching breakers, phases, relays, and controller packages.
Critical differences
Compact Harvia WKM3/M16 wood stove for small sauna rooms; product planning uses the Harvia WKM3 data-sheet footprint while the CAD route uses the official Harvia M3 SAT archive. T600 chimney path required; use Harvia WHP steel chimney kit/extensions/damper or an AHJ-approved equivalent specified by the installer.
10 more notes shown below.
Fuel / standard
Wood / EN 15821:2010
Manual states this stove is not suitable for a shared flue system.
Manual dimensions
390 mm W x 430 mm D x 715 mm H
The designer uses Harvia's current product/CAD envelope of 390 mm W x 450 mm D x 710 mm H.
3D model basis
Official WKM3 stove CAD scaled to the page data-sheet footprint plus dimensioned WL400/WL450 shield overlay
Harvia PIM lists WKM3 2D/3D CAD, while the SaunaMarketplace-attached Harvia WKM3 data sheet lists a 450 mm product depth and WL400/WL450 product assets expose the safety-distance PDF, WL protective-sheath manual, and product images rather than a standalone shield CAD model.
Flue class / diameter
T600; 115 mm connection; 110 mm min pipe ID
Connection locations: Top, Rear. CAD top flue center is 103.6 mm forward from the back.
Weight / stones
44.2 kg (97.4 lb) body; 30 kg (66.1 lb) stones; 10 cm-15 cm stone size
Use peridotite, olivine diabase, olivine, or vulcanite stones intended for sauna heaters. Wash stone dust off before loading; place larger stones lower and smaller stones higher. Stack stones loosely for air circulation and do not pack stones against or on top of the surrounding grate. Decorative stones are only for the top layer and must not touch the hot inner frame of a wood stove.
Combustion test data
12 Pa draft; 374 C flue gas; 14.5 g/s mass flow
Manufacturer declaration data under EN 15821:2010; stove door closed.
Efficiency / emissions
69% efficiency; 0.65% CO at 13% O2; 8146 mg/m3 CO
Use this as manufacturer comparison data, not as a field-adjustable design input.
Firewood / firing
35 cm max length; 8 cm-15 cm diameter; 2.7 kg ignition; 3.2 kg refuel; 10 mm ash-box gap after ignition
Use dry wood; avoid high-thermal-value fuels such as chipboard, plastic, coal, briquettes, or pellets. Do not burn painted or impregnated wood, waste, garden waste, or liquid fuel. The stove is not intended to operate with the stove door open.
Non-combustible clearance
100 mm (3.94") side; 100 mm (3.94") rear; 50 mm masonry air gap; 100 mm recessed masonry air gap
Combustible clearances remain the row clearances in the size table.
Protective sheath clearance
WL400/WL450: 50 mm (1.97") side / 50 mm (1.97") rear
Harvia safety-distance drawing lists WL400/WL450 for M1, M2, M3, and M3 SL; side/rear clearances reduce to 50 mm with the sheath, while the stove-door/front clearance remains 300 mm. The same safety-distance table lists 30 mm for the sheath assembly gap.
Floor protection
60 mm minimum concrete slab before no special stove protection
Concrete floor needs no special stove protection only when the slab is at least 60 mm thick and has no wires or water pipes below the stove. Tile assemblies and combustible floors need Harvia protective bedding or equivalent heat-radiation protection. Combustible flooring in front of the stove door needs nonflammable floor protection.
Sauna ventilation
Gravity or mechanical exhaust layouts supported
Gravity ventilation: fresh air inlet close to the floor near the stove, exhaust far from the stove near the ceiling. Mechanical exhaust ventilation: fresh air inlet about 500 mm above the stove, exhaust close to the floor such as below the bench.
WHP chimney clearance
100 mm insulated chimney to combustibles; 500 mm single-wall pipe to walls; 1000 mm single-wall pipe to ceiling
Keep at least 430 mm of insulated chimney visible in the room. Lead-through insulation against the pipe is capped at 200 mm in insulated buildings. Lead-through insulation must be class A or long-term rated at 750 C or more.
WHP chimney limits
5 m max chimney elements; 2 m max freestanding element; 3 m max indoor lateral-support spacing
Silicone vapor collar at sauna ceiling needs 160 C continuous heat resistance.
Setup details
First heat outdoors without stones; M3 has no adjustable legs; Door can open left or right
Do not throw water during the first heating; place stones only after the stove has cooled completely.
Maintenance
Ash, stones, smoke canals, and chimney are recurring checks
Empty the ash box before each heating so combustion air cools the grate. Remove soot and ash from stove smoke canals through the soot openings from time to time. Rearrange stones at least annually and more often in frequent use; remove stone debris and replace broken stones. Sweep the chimney and connection pipes regularly and after long idle periods.
Manual accessories
WHP1500 steel chimney, WHP1500BSM black barrel-sauna chimney kit, WHP1000 1000 mm steel chimney extension, WHP500 500 mm steel chimney extension
WHM25 vapor barrier collar, WHP270SP smoke damper, SP139/SP139M rain cap service part, SPWHM22 rain flange service part, SPWHM23 rain flange installation set, VL22l pipe-model water heater, WZ020130 radiation cover, WX017 / WL400/WL450 M-series protective sheath, WX018 / WL100 / WL110 protective bedding, Angle smoke pipe, WZ020115 smoke-pipe lead-through flange, WZ011115 masonry connector
- Compact Harvia WKM3/M16 wood stove for small sauna rooms; product planning uses the Harvia WKM3 data-sheet footprint while the CAD route uses the official Harvia M3 SAT archive.
- T600 chimney path required; use Harvia WHP steel chimney kit/extensions/damper or an AHJ-approved equivalent specified by the installer.
- Align the WHP chimney and roof/ceiling lead-through to the CAD top flue collar, which is offset toward the rear of the M3 body.
- Non-combustible base, heat shields, roof/ceiling lead-through, combustion air, and local fire-code review required.
- The Harvia WKM3 data sheet attached to the SaunaMarketplace M3 page lists M3 safety distances with stones placed per the manual: 300 mm front/back combustible clearance, 250 mm side combustible clearance, and 1.2 m ceiling clearance.
- With the Harvia WL400/WL450 M-series protective sheath installed per the safety drawing, M3 side and rear combustible clearances reduce to 50 mm while front clearance remains 300 mm.
- M3 SL feeds through the wall (430 mm body + 210 mm firebox extension). Manual 301-Pk Fig 7: side 250, back 300, front 300, ceiling 1200 mm; WL400/WL450 sheath cuts side/back to 50 mm.
- Not currently on SaunaMarketplace; sourced via Harvia US (BathingBrands).
- Use the WKM3 product specs and the SaunaMarketplace-attached Harvia WKM3 data sheet together with the Harvia wood-stove manual, WL400/WL450 protective-sheath safety-distance drawing/manual/images, WHP chimney manuals, SAT-derived rear-offset top flue, and local code review.
- M3 uses the official Harvia WKM3 SAT-derived GLB with the SaunaMarketplace-attached Harvia WKM3 data-sheet footprint, room-volume, and clearance data.
- WL400/WL450 shield visualization is a Harvia-dimensioned planning overlay; Harvia publishes the shield safety/manual/image assets, but not a standalone shield CAD file in the public PIM/designer data.
- Harvia M3 planning should pair the selected WKM3 stove body with 10-15 cm stones, a T600 chimney path, WHP chimney kit/extensions/damper, non-combustible base, and local AHJ review.