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WOODBRIDGE OBS1812-A Outdoor Barrel Sauna – Thermo Finnish Pine with Harvia Heater, 4' × 6'
WOODBRIDGE OBS1812-A Outdoor Barrel Sauna – Thermo Finnish Pine with Harvia Heater, 4' × 6'
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The OBS1812-A is an outdoor barrel sauna built from thermo-treated Finnish pine and heated by a Harvia electric heater — the Finnish manufacturer that has been building sauna heaters since 1950 and is the name most often found in commercial saunas. On a barrel sauna at this size, the heater is the component that determines whether you use it twice a year or twice a week, and it is the single biggest difference between this kit and a generic barrel sauna.
The barrel shape is not styling. In a square cabin, heat rises and pools against the ceiling, leaving your feet cold while your head is too hot. The curved walls send heat back down and around, so it circulates through the cabin instead of collecting at the top, and the room reaches an even temperature throughout. Less air to heat also means it gets there faster: 175–185°F in 45 to 60 minutes from cold.
A half-view window runs across the front so you can see out while you sit, 304-grade stainless steel bands pull the staves tight, and a black asphalt shingle roof sheds weather and holds heat in. It seats two to three.
Key Features
Harvia 4.5 kW electric heater with sauna stones
- Harvia is the Finnish heater manufacturer used throughout the commercial sauna industry.
- 4.5 kW output, sized for this cabin volume.
- Reaches 175–185°F in 45 to 60 minutes from cold.
- Sauna stones included — pour water over them for steam and humidity.
- 240 V, 30 amp, hard-wired connection.
Thermo-treated Finnish pine
- 1-3/8" thick Finnish pine, thermally modified using heat rather than chemical preservatives.
- Thermal treatment reduces the wood's moisture absorption, so it is more stable against warping and swelling in an outdoor, high-humidity application.
- No chemical preservatives used in the treatment process.
- Staves and end sections arrive pre-assembled into profiles.
Barrel shape for even heat
- Curved walls circulate heat back down through the cabin rather than letting it pool at the ceiling.
- Even temperature from bench height to head height.
- Smaller air volume than a square cabin of the same footprint, so it heats faster and holds temperature with less energy.
Half-view window
- Wide window across the front wall.
- See out to the garden while you sit rather than facing a solid wall.
- Brings daylight into the cabin and makes the space feel less enclosed.
304-grade stainless steel bands and fixings
- 304 stainless steel barrel bands draw the staves tight against each other.
- A tighter build means fewer gaps and less heat escaping.
- Stainless hinges and fasteners throughout — the grade that matters on a structure sitting outdoors year-round.
Asphalt shingle roof
- Black asphalt shingle roofing kit included.
- Sheds rain and snow off the curve of the barrel.
- Adds a layer of insulation above the staves, helping the cabin hold heat.
Specifications
| Model | OBS1812-A |
| Capacity | 2–3 persons |
| Barrel exterior dimensions | 47-1/4" (L) × 70-7/8" (W) × 70-7/8" (H) |
| Base cradle dimensions | 47" (L) × 4" (D) |
| Wood | Thermo-treated Finnish pine, 1-3/8" thick |
| Bands and fixings | 304-grade stainless steel bands, hinges and fasteners |
| Heater | Harvia electric, 4.5 kW |
| Heater electrical | 240 V, 30 amp, hard-wired |
| Operating temperature | 175–185°F in 45–60 minutes from cold |
| Window | Half-view window |
| Roof | Black asphalt shingle |
| Installation | Two people required throughout assembly |
| Brand | WOODBRIDGE |
What's Included
- Barrel sauna kit × 1
- Harvia electric heater × 1
- Sauna stones
- Black asphalt shingle roof kit × 1
- Base cradles
- Wood benches
- Sauna accessories kit
Before You Order
- You will need a licensed electrician. The heater is hard-wired to a dedicated 240 V, 30 amp circuit. This is not a plug-in appliance, and the wiring is a separate job from the sauna assembly. Get a quote before you order, because it is a real part of the total cost.
- Assembly takes two people from start to finish. The manufacturer specifies two people for the entire installation, not just for lifting the heavy sections.
- Prepare the base first. The sauna sits on two cradles that must be level and parallel to each other on firm, level ground. Get this right before the kit arrives — everything above it depends on it.
- Check local codes and permits. WOODBRIDGE does not take responsibility for local code compliance, so confirm with your municipality whether an outdoor structure of this size and a 240 V circuit require a permit or inspection where you live.
- Allow clearance around the barrel for airflow, drainage and access to the electrical connection, and site it where rain and snow run off cleanly.
- Residential use only. Commercial installation voids the warranty.
Warranty
One-year limited warranty covering defects in the heater and its components. Commercial installation voids the warranty.
Care and Maintenance
- After each use: leave the door ajar so the cabin dries out fully. Trapped moisture is what damages sauna interiors.
- Regularly: wipe benches down and let them dry; sweep the floor and clear debris from around the heater.
- Periodically: check the tension on the stainless bands and re-tighten as the staves settle, particularly through the first season and after temperature swings.
- Annually: inspect the shingle roof, the door seal and the cradles, and check the sauna stones — stones break down over time and should be rearranged or replaced when they start to crumble.
- Keep the roof clear of leaves and snow load.
Safety Information
Installation must follow the manufacturer's instructions in full; incorrect handling during assembly can cause serious injury. All electrical work must be carried out by a licensed electrician in accordance with local codes. Do not pour water anywhere other than on the sauna stones. Keep the area around the heater clear at all times and never cover it. Do not leave children unattended in or near the sauna, and never leave the sauna running unattended. Use for residential purposes only.
Sauna bathing raises your core body temperature and heart rate. Limit sessions, cool down between them and drink water. Do not use the sauna under the influence of alcohol or if you are pregnant. If you have a heart condition, low or high blood pressure, circulatory problems, or any other medical condition, or you are taking medication, consult a qualified physician before using a sauna.
