Indoor vs. Outdoor Hot Tubs: Which Is Right for You?

One of the first decisions when you buy a hot tub is whether it goes indoors or outdoors. Both have their advantages and their challenges. Here is how they compare.

Outdoor hot tubs: the classic choice

Pros:

• Fresh air: enjoy the stars, cool air on your face or the garden around you while you soak.
• No humidity problems: steam simply disappears into the open air.
• More space: patios, gardens and decks usually have more room than indoors.
• Good for guests: great for get-togethers, parties and family evenings.

Things to consider:

• The weather: you will need a good cover, and perhaps a parasol or gazebo for rainy days.
• Plumbing and electrics: more planning is needed if the spa is a long way from the house.
• Privacy: depending on your garden, neighbours may be able to see in unless you add fencing or screens.

Best for:
People who love fresh air, have outdoor space and want the traditional hot tub experience.

Indoor hot tubs: private and convenient

Pros:

• Comfortable all year: no need to brave the cold or rain.
• Complete privacy: ideal if you like to soak on your own or keep your spa time private.
• More secure: protected from theft, wildlife and the weather.
• Part of a home spa: it can sit alongside a sauna, steam room or home gym.

Things to consider:

• Ventilation is essential: you need good airflow to control humidity and prevent mould.
• Structural planning: hot tubs are heavy. The floor must be strong enough and properly waterproofed.
• Installation can cost more: especially if the room isn't already set up for a spa.

Best for:
Homeowners with a suitable indoor space, such as a conservatory, basement or spa room, who value convenience and privacy.

Questions to ask yourself

• Do I want to use the hot tub in all weathers?
• How much space do I have indoors and outdoors?
• Am I after sociable evenings or quiet, private soaks?
• Can my indoor space cope with the moisture and weight?
• Do I prefer fresh air or a warm, controlled room?

Indoor or outdoor at a glance

	Outdoor	Indoor
Base	Level concrete slab, paving on a firm base, or a deck built for the load	A floor checked for the filled weight, usually ground-bearing concrete
Moisture	Steam disperses into the open air	Needs extraction or dehumidification to stop condensation and mould
Weather	Cover essential; shelter helps in wind and rain	No weather, use it in any season in comfort
Running costs	More heat lost on cold, windy nights	Less heat loss, but ventilation and dehumidifier add their own costs
Delivery and access	Clear route through the garden	Doorways, corridors and turns must fit the tub on its side
Drainage	Drain to a foul drain or sloping paving	A floor drain or a pump to an outlet is needed
Build cost	Usually lower	Usually higher, especially if the room needs work

Floor loading for indoor installs

A filled hot tub is one of the heaviest things you can put in a house, and the load is concentrated on a small area. The figures below use filled weights from our product pages plus 75 kg per adult at full seating, spread over the tub's footprint:

Model	Filled weight	Footprint	Load with bathers
Yukon	490 kg	213 x 100 cm	about 300 kg per m²
Calgary	930 kg	213 x 150 cm	about 385 kg per m²
Winnipeg	1,225 kg	198 x 198 cm	about 425 kg per m²
Toronto	1,380 kg	213 x 213 cm	about 400 kg per m²
Niagara	1,945 kg	228 x 228 cm	about 475 kg per m²

That is well beyond what an ordinary suspended timber floor in a house is designed to carry. A ground-floor concrete slab on solid ground is the usual answer. For any upstairs room, conservatory, garage with a suspended floor or new extension, ask a structural engineer to check the floor before you order. Ask them to look at waterproofing too, so a splash or a slow leak cannot reach the structure underneath.

Ventilation and humidity control

Warm water gives off moisture all the time, and far more when the cover is off. Indoors, that moisture settles on the coldest surfaces first: windows, outside walls and ceilings. Without a plan, the result is condensation, peeling paint and mould. To keep the room healthy:

1. Keep the cover on whenever the tub is not in use. It is the cheapest and most effective moisture control you have.
2. Fit mechanical extraction. An extractor fan ducted to outside, sized for the room, removes moist air during and after a soak.
3. Add a dehumidifier for rooms that are used often or have little natural airflow.
4. Choose moisture-resistant finishes. Tiled or sealed floors and walls cope far better than plasterboard and carpet.
5. Keep chemicals ventilated. After dosing, leave the cover open for about 30 minutes with the extractor running so the air clears.

Base options for outdoor installs

• Concrete slab: the most solid option for any tub, and the usual choice for larger 32 amp models. Make it level and slightly larger than the tub.
• Paving slabs: fine when laid on a properly compacted, level base. Slabs on soft ground can sink unevenly under the weight.
• Decking: works well if the deck is designed for the filled weight plus bathers. Have a builder confirm the joists and supports. Our guide to deck or patio installation covers the choice in detail.
• Grass or gravel alone: not suitable. The tub needs a flat, firm, level surface under the whole base.

Outdoors, a shelter makes the tub far more usable in a British winter. A gazebo keeps the rain off and breaks the wind, as long as you leave room for the cover to fold back.

Electrics indoors and out

The rules are the same wherever the tub goes. A plug and play model needs a dedicated 13 amp socket that can supply the full 13 amps, and a larger tub needs a dedicated 230V, 32 amp supply with an RCD, fitted by a qualified electrician. Indoors, sockets and switches in a room with a hot tub need particular care because of the water, so involve your electrician at the planning stage. Browse our 13 amp plug and play tubs or the larger models in our five seats or more range.

Service access and everyday practicalities

Wherever the tub goes, an engineer will one day need to reach the pumps and control pack behind the cabinet panels. Indoors, it is tempting to build a tub into a platform or tile right up to it. If you do, leave a removable panel on the service side and enough floor space to kneel in front of it. Outdoors, avoid boxing that side in with posts, planters or fixed seating.

Think about the small things too. Indoors, you will want somewhere to hang towels that will not get steamy, a non-slip floor around the tub and a place to keep chemicals locked away from children. Outdoors, a short, lit path from the back door, a hook for robes and a dry box for the test strips all make the tub easier to use on a dark winter evening.

Indoor and outdoor FAQs

Can I put a hot tub in a conservatory?

Possibly, but conservatories are often built on light foundations and get very humid. Have a structural engineer check the floor, and plan ventilation before the tub arrives.

Can a hot tub go upstairs?

Only if a structural engineer confirms the floor can carry it. Most upstairs floors in UK homes cannot without strengthening.

Is an indoor hot tub cheaper to run?

It loses less heat, but the cost of extraction and dehumidification can offset some of the saving.

How do I drain an indoor hot tub?

You need a floor drain or a pump to a suitable outlet. A submersible pump with hose makes this easier.

Will a hot tub fit through my doors?

Tubs are moved on their side on a trolley, so measure the clear width and height of every door, corridor and turn on the route and compare them with the tub's dimensions. Our team can check the measurements with you on 01293 824094.

It depends on how you live

There is no single right answer. If you want to relax outdoors under the stars, a garden hot tub is ideal. If privacy and year-round comfort matter most, an indoor setup may be worth the extra planning.

Either way, our team is happy to help you decide and find the right model for your home.

Choosing a hot tub?

Compare our hot tubs and swim spas, or visit our showroom near Gatwick.

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