Step 1: Choose the Right Type for Your Space
Before anything else, decide where your sauna will live. Indoor saunas (in a bathroom, spare room, or garage) are protected from weather and easier to access year-round but require adequate ventilation. Outdoor saunas (barrel, cabin, or custom shed) are more dramatic and allow natural ventilation, but require weatherproofing and an electrical run from your home.
Space requirements: a 2-person sauna needs approximately 4×4 feet of interior space. A 4-person sauna needs 5×7 feet minimum. Add clearance around the exterior for doors and airflow.
Step 2: Choose Infrared vs Traditional
Go infrared if: You want faster setup (plugs in, heats in 15 minutes), you can't do major electrical work, you prefer lower air temperatures (120–140°F), or you're on a tighter budget.
Go traditional if: You want an authentic high-heat experience (160–185°F), you love the steam-pouring ritual (löyly), or you're building for the long term and want maximum durability.
For more detail, see our full home sauna guide.
Step 3: Handle the Electrical Requirements
This is where many people get surprised. Traditional electric heaters above 6kW (most 2+ person units) require a dedicated 240V circuit, typically 40–60A. This is the same type of circuit used for electric dryers or ovens. If you don't already have a spare 240V circuit available in the right location, hire a licensed electrician — costs typically $300–800 depending on distance from your panel.
Most 1-person infrared cabins run on 120V, 15A standard household circuits. Many 2-person infrared units require 240V. Always verify the spec sheet before purchase.
Step 4: Prepare the Space
For indoor installation: ensure the floor is level, clear the space, and verify ventilation. Traditional saunas need a fresh-air intake near the floor and an exhaust near the top — this can be a simple louvered vent or window. The room or alcove should ideally have a non-carpeted floor (tile or concrete) for water resistance.
For outdoor installation: prepare a level pad (gravel, pavers, or concrete), ensure weather protection for the electrical connection, and plan your drainage. Outdoor sauna exteriors should be treated or made from weather-resistant wood (red cedar, spruce) with exterior staining every 2–3 years.
Step 5: Assembly
Infrared cabin kits arrive as pre-cut panels with numbered pieces — assembly takes 2–4 hours for one person and is simpler than most flat-pack furniture. Traditional sauna kits take a weekend for two people. Custom-built saunas require a contractor and 1–3 weeks of build time.
Follow the manufacturer's instructions precisely for electrical connections. If in doubt, have a licensed electrician complete the final connection.
Step 6: First Use and Seasoning
Before your first sauna session, run the empty sauna at full temperature for 1–2 hours to cure the wood and burn off any manufacturing residues. Open the door periodically to ventilate. After this seasoning run, your sauna is ready for regular use.