Choosing between an indoor and outdoor sauna is one of the most important decisions you'll make when investing in home wellness.

Unlike selecting a heater, timber species or bench layout, the location of your sauna influences almost every aspect of ownership, from installation costs and planning considerations to how frequently you use it and whether it complements your property's layout.

Both indoor and outdoor saunas deliver the same core experience and can be equipped with identical electric or wood-fired heaters. The health benefits associated with regular sauna bathing are determined by the quality of the heat and the consistency of use, not whether the sauna sits inside your home or in the garden.

The differences are therefore practical rather than physiological.

An indoor sauna integrates into the existing fabric of your home and prioritises convenience. An outdoor sauna creates a dedicated wellness space that preserves valuable internal floor area while allowing greater design flexibility. Neither approach is inherently superior, but each is better suited to different property types and lifestyles.

As the UK sauna market continues to expand, understanding these differences has become increasingly important. According to Grand View Research, the UK now represents the largest national market within Europe for sauna installations, with residential purchases accounting for the majority of demand. Homeowners are no longer viewing saunas as niche luxury products but as long-term investments in health, wellbeing and property enhancement.

The decision should therefore be approached in exactly the same way as any major home improvement: by assessing how well the installation fits your property both today and over the next twenty years.

Understanding How the Two Installations Differ

At first glance, the distinction appears obvious—one sauna is inside the house and the other is outside. In practice, the implications are considerably more significant.

An indoor sauna becomes part of the building. It shares the home's services, sits within its thermal envelope and relies upon existing rooms for circulation, ventilation and access. The available space largely dictates the size of the sauna, and installation is often designed around the constraints of the existing building.

An outdoor sauna is effectively a standalone structure. It functions independently from the house while still requiring electrical supply, suitable foundations and appropriate access. Because it is not constrained by internal walls, outdoor installations generally offer greater flexibility in terms of layout, glazing, ceiling height and surrounding landscaping.

This distinction influences every stage of ownership, from installation through to maintenance and future expansion.

Property Suitability

The most suitable location is often determined by the property itself rather than personal preference.

Properties with dedicated gyms, swimming pools, basements or large utility areas frequently lend themselves well to indoor installations. These homes often already possess suitable electrical infrastructure, shower facilities and sufficient internal space to create a complete wellness suite.

Conversely, detached houses with generous gardens frequently benefit more from outdoor saunas. Rather than sacrificing valuable internal accommodation, homeowners can create an entirely separate wellness building that complements other external features such as outdoor kitchens, pergolas, swimming pools or cold plunge pools.

Urban properties also require careful consideration. In London and other major cities, internal floor space often commands a premium. Converting a spare bedroom into a sauna may reduce the flexibility of the property more than installing a compact garden sauna.

The objective should always be to enhance the property rather than compromise its primary function.

Installation Requirements

Installation complexity is frequently misunderstood.

Many buyers assume that installing a sauna indoors is simpler because the building already exists. In reality, internal installations often require more detailed planning.

Every sauna component must be transported through the property before assembly begins. Door widths, staircases, ceiling heights and corridor dimensions all need to be assessed. Ventilation also becomes considerably more important, as heat and moisture must be managed without affecting neighbouring rooms.

Outdoor installations introduce a different set of requirements.

The primary considerations become the construction of a suitable base, routing electrical services to the building and ensuring adequate drainage around the structure. Once these elements have been addressed, assembly is often more straightforward because installers have unrestricted access to the site.

Neither installation method is universally easier. The overall complexity depends entirely on the existing property.

Indoor Saunas: Where They Excel

The principal advantage of an indoor sauna is integration.

When incorporated into a home gym, spa bathroom or wellness suite, the sauna becomes part of an existing daily routine. Users can move directly between exercise, showering and sauna bathing without leaving the building, making spontaneous use considerably easier throughout the year.

Indoor installations also benefit from complete protection against external weather conditions. Timber is not exposed to ultraviolet light, rain or frost, reducing the amount of exterior maintenance required over the lifespan of the sauna.

Another advantage is environmental stability. Because the sauna sits within a heated building, it is less affected by external temperature fluctuations, which can contribute to marginally faster heat-up times depending on the construction of the cabin.

However, these benefits come with trade-offs.

Indoor saunas permanently occupy internal floor space and generally offer less flexibility for future expansion. If homeowners later wish to introduce cold plunge pools, outdoor showers or additional relaxation areas, these additions may be constrained by the available accommodation.

For homeowners already developing an integrated wellness suite, these compromises are often acceptable. For others, dedicating an entire room to a sauna may represent a significant opportunity cost.

Outdoor Saunas: Why Demand Is Growing

The strongest trend within the UK residential sauna market has undoubtedly been the growth of outdoor installations.

This reflects wider changes in residential design rather than changes in sauna technology. Gardens are increasingly viewed as functional living spaces capable of accommodating offices, gyms, kitchens and wellness facilities. A standalone sauna fits naturally within this evolution because it creates a dedicated destination without reducing the usable accommodation inside the house.

Outdoor saunas also provide substantially greater design freedom. Larger glazing panels, panoramic views, external terraces, covered seating areas and integrated cold-water therapy can all be incorporated far more easily than within a conventional indoor installation.

Many of the UK's most recognised public sauna businesses—including Soul Water Sauna, Sauna Social Club, Sea Scrub Sauna and numerous coastal operators—have demonstrated the appeal of this approach. While these are commercial businesses, they reflect broader consumer demand for outdoor wellness experiences that combine heat, fresh air and natural surroundings.

The growing popularity of garden wellness spaces suggests that this trend is likely to continue as homeowners seek to maximise the potential of their outdoor environments.

Installation Cost: Looking Beyond the Sauna

One of the most common mistakes buyers make is comparing only the purchase price of the sauna itself.

The total project cost is determined by the entire installation.

Consideration	Indoor Sauna	Outdoor Sauna
Internal building alterations	Often required	Rarely required
Concrete or paving base	Usually not required	Usually required
Ventilation upgrades	Often required	Usually simpler
External electrical connection	Rarely required	Commonly required
Impact on internal floor space	Permanent	None
Future relocation	Difficult	Sometimes possible

In many cases, the installation costs of indoor and outdoor saunas are remarkably similar once all associated building works are considered.

The correct comparison is therefore the total installed project cost, not the advertised retail price of the sauna.

Running Costs

Running costs are often assumed to be significantly higher for outdoor saunas. In reality, build quality plays a much greater role than location.

Modern outdoor saunas use insulated wall systems, high-performance glazing and vapour barriers specifically designed for Scandinavian climates that are considerably harsher than those experienced in the UK.

An efficiently insulated outdoor sauna may consume very similar amounts of energy to an indoor model equipped with the same heater.

Instead, running costs are influenced primarily by:

• Heater output
• Cabin volume
• Frequency of use
• Insulation quality
• Heat-up time
• Ambient outdoor temperature

Selecting an appropriately sized heater and purchasing a well-insulated cabin will generally have a greater impact on energy consumption than whether the sauna is located inside or outside.

Long-Term Flexibility

A home rarely remains unchanged for twenty years.

Families grow, lifestyles evolve and additional wellness features often follow.

This is where outdoor saunas possess a distinct advantage.

Future additions such as cold plunge pools, outdoor showers, relaxation decks, pergolas or changing rooms can usually be incorporated without affecting the existing house. Expansion therefore becomes considerably easier.

Indoor installations are naturally constrained by the available accommodation. Enlarging the sauna or introducing complementary wellness features often requires sacrificing additional internal rooms.

Homeowners planning a long-term wellness project should therefore consider not only today's requirements but also how the space may evolve over the coming decade.

Maintenance Requirements

Both indoor and outdoor saunas require surprisingly little maintenance when constructed from quality materials.

Indoor installations benefit from complete protection against the weather and therefore require only routine cleaning, occasional inspection of the heater and replacement of sauna stones when necessary.

Outdoor saunas require periodic inspection of external cladding and protective finishes, depending on the timber species used. Premium thermowood, cedar and Scandinavian spruce are specifically selected for their dimensional stability and durability in challenging climates, making maintenance requirements relatively modest when properly installed.

Neither option should be considered maintenance-intensive, provided high-quality materials have been used from the outset.

Property Value and Buyer Appeal

Although there is currently little UK research assigning a precise financial premium to homes with saunas, broader property trends are clear.

Premium wellness features are becoming increasingly desirable, particularly in higher-value residential markets. Estate agents regularly report growing demand for homes incorporating gyms, spa bathrooms, swimming pools and outdoor lifestyle spaces.

An indoor sauna strengthens the appeal of a dedicated wellness suite.

An outdoor sauna enhances the overall functionality of the garden while preserving the property's internal accommodation.

From a resale perspective, preserving valuable living space often broadens buyer appeal, particularly where the sauna has been positioned as part of a wider outdoor wellness area rather than replacing an existing bedroom or reception room.

Indoor vs Outdoor Sauna: At a Glance

Factor	Indoor Sauna	Outdoor Sauna
Best suited to	Home gyms, basements, spa rooms	Gardens, pools, wellness retreats
Installation access	Can be restrictive	Generally easier
Uses internal floor space	Yes	No
Expansion potential	Limited	Excellent
Ventilation complexity	Higher	Lower
Weather exposure	None	External only
Maintenance	Slightly lower	Slightly higher
Cold plunge integration	Possible	Excellent
Creates a dedicated wellness destination	Limited	Excellent

Which Should You Choose?

An indoor sauna is generally the better option where convenience, year-round accessibility and integration with existing wellness facilities are the primary objectives. It works particularly well within home gyms, swimming pool complexes and purpose-built spa suites where supporting infrastructure already exists.

An outdoor sauna is often the stronger long-term investment for detached and semi-detached properties with sufficient external space. It preserves valuable accommodation inside the house, provides greater design flexibility and allows homeowners to develop a complete outdoor wellness environment incorporating features such as cold plunge pools, outdoor showers and relaxation terraces.

There is no universally correct answer.

The most successful installations are those that complement the architecture of the property rather than working against it.

Final Thoughts

Both indoor and outdoor saunas deliver the same core purpose: providing a high-quality heat bathing experience that supports relaxation, recovery and wellbeing. The decision should therefore be based not on perceived health differences, but on how each installation integrates with your home.

For properties where internal space is abundant and a dedicated wellness suite already exists, an indoor sauna offers exceptional convenience and seamless integration. For homeowners with suitable gardens, however, an outdoor sauna provides greater long-term flexibility and reflects the direction in which the UK residential wellness market is increasingly moving.

Ultimately, the best sauna is not determined by whether it sits inside or outside. It is the one that has been carefully matched to the property, professionally installed and used consistently for many years to come.