Can An Outdoor Sauna Be Used Indoors

Dec 27, 2025

British weather and limited space make indoor sauna setups tempting. So, can an outdoor sauna be used indoors? Yes—but only with the right adjustments. Outdoor Saunas bring benefits, but safety, ventilation, electrics, moisture control, and UK regulations all matter. Read on before turning up the heat indoors.

Assessing the Technical and Structural Feasibility

In the UK, many people enjoy the benefits of saunas, from relaxation to improved heart health. However, not everyone has sufficient outdoor space for a traditional installation. Outdoor and indoor saunas share the same purpose, but their construction and intended environments differ.

Before bringing an outdoor sauna inside, it is essential to assess whether the structure and surrounding space can safely support it.

Modern outdoor sauna pod with large glass window and open door on decking.

Physical Constraints: Height, Weight, and Clearance

Outdoor saunas are often bulkier and heavier than indoor models.
Evaluating physical limitations is a critical first step before installation.

Ceiling Height: Ensuring Enough Space for the Roof Peak and Airflow

Many outdoor saunas feature pitched or peaked roofs designed for rain runoff.
When installed indoors, sufficient ceiling height is required to accommodate the roof structure.

Adequate vertical space is also needed to allow proper airflow and heat circulation.

Weight Distribution: Can Your Joists Support a Solid Wood Sauna?

Outdoor saunas are typically constructed from solid timber and can be extremely heavy.
Floors, particularly on upper levels, must be able to support the weight without compromising structural integrity.

A structural assessment may be required before installation.

The Door Clearance Rule: Why Outward-Opening Doors Need Space

For safety reasons, sauna doors usually open outward.
Indoors, this requires enough clearance to ensure the door can open fully without obstruction.

Restricted door movement can create safety risks during use.

Electrical and Heating Considerations for Indoor Use

Heating systems designed for outdoor use may require modification when relocated indoors.
Electrical safety becomes a primary concern in enclosed spaces.

Electric vs. Infrared: The Only Safe Options for Indoor Placement

For indoor installations, electric and infrared heaters are the only safe and practical options.
These systems are designed specifically for enclosed environments and controlled airflow.

They also comply more easily with UK electrical regulations.

Black modern outdoor sauna with glass door, chimney, and slatted privacy screen.

Why Wood-Burning Stoves are Strictly Prohibited Indoors (Carbon Monoxide)

Wood-burning stoves, sometimes found in outdoor saunas, are unsuitable for indoor use.
They pose serious carbon monoxide risks and require ventilation levels that most homes cannot provide.

As a result, they are strictly prohibited indoors.

Dedicated Circuits: 240V Requirements for Traditional Electric Heaters

Many traditional electric sauna heaters require a dedicated 240V circuit.
A qualified electrician should confirm that your home’s electrical system can support this safely.

All electrical work must comply with UK building and safety regulations.

Protecting Your Home from Moisture and Heat Damage

High heat and humidity are unavoidable during sauna use. Without proper control, moisture can damage surrounding materials and create long-term issues.

Critical Flooring and Ventilation Requirements

Moisture management plays a key role in protecting your home.
Inadequate flooring or ventilation can lead to mould, rot, and structural damage.

Waterproof Foundations: Why Tile and Vinyl Beat Carpet and Hardwood

Tile and vinyl flooring offer far better resistance to moisture and heat.
Carpet and hardwood absorb moisture, making them unsuitable beneath an indoor sauna.

Waterproof surfaces also make cleaning and maintenance easier.

Mechanical Ventilation: Managing 190°F Heat and Humidity Indoors

Indoor saunas require proper ventilation to remove excess heat and humidity.
Mechanical ventilation systems help regulate air quality and temperature.

Without them, moisture can quickly build up in surrounding rooms.

The 1-Inch Air Gap: Preventing Mould Between Sauna and House Walls

Leaving a small air gap between the sauna and adjacent walls improves airflow.
This gap helps prevent trapped moisture and reduces the risk of mould growth.

It also protects the home’s internal structure over time.

Outdoor sauna pod with curved roof and glass door set on patio near garden seating.

Exterior Treatment and Aesthetics

Outdoor saunas are designed to withstand constant exposure to the elements.
Indoors, some of these features may be unnecessary or unsuitable.

To Stain or Not to Stain? Maintenance Differences for Indoor Use

Indoor environments reduce the need for heavy exterior staining.
However, finishes should still be suitable for high heat and humidity conditions.

Using the correct treatment helps extend the sauna’s lifespan.

Removing the Asphalt Roof: Adapting Outdoor Kits for Interior Rooms

Some outdoor sauna kits include asphalt roofing materials.
These are unnecessary indoors and may need to be removed or replaced.

Adapting the roof improves safety, appearance, and compatibility with interior spaces.