Best inflatable hot tub for a small garden: what to look for (UK)

In a small garden the real question is not "which tub is best" but "which tub fits, with the clearance, socket and ground it needs". A tub that is 20 cm too wide, or a socket that is the wrong distance away, rules out an otherwise good model.

This guide uses published manufacturer and retailer specifications, checked on 12 November 2026. We have not tested any tubs, and we do not name a single winner. Instead you will get the measurements and checks that let you build a shortlist that genuinely suits your space.

The short answer

For most small gardens, shortlist round or square tubs of roughly 155 to 180 cm external width, with a published water volume of around 650 to 700 litres, a heater of 1,350 to 2,200 W, and a power cable long enough to reach a safely positioned outdoor socket. Then check three things before you buy: the width including the pump unit, the clearance the manufacturer asks for, and what the tub will stand on.

Step 1: Measure the space the tub really needs

The footprint is wider than the tub

Many inflatables have an external pump unit that sticks out from the side. The Lay-Z-Spa Miami AirJet is listed at 180 cm wide and 66 cm high, but 223 cm wide including the pump. If you only measure the 180 cm circle, you can lose over 40 cm of the space you thought you had.

Add the clearance

Lay-Z-Spa recommends 1 metre of clearance around the tub, and says its compact Oslo-style models need about 2.8 metres of total space including that clearance. Its owner manual for the Miami asks for at least 1 metre from surrounding objects and at least 2 metres from metal surfaces, and says to keep the tub away from overhead power lines, trees, underground utilities and house entrances.

Worked example: a 180 cm tub with 1 metre on every side needs a square of 3.8 metres (1.8 + 1.0 + 1.0). A 155 cm tub needs 3.55 metres. If your patio is 3 metres square, you are in "check the manual very carefully" territory rather than "it will fit".

Step 2: Compare the numbers that matter

These are examples of the published range, not recommendations. Always confirm the figures on the page of the exact model you are buying, because manufacturers revise models often.

The MSpa rows come from a third-party compilation of MSpa specifications, so verify them on the current retailer page. The other rows come from the manufacturer or retailer pages listed in the sources.

Look at internal width, not just "4 person"

The stated capacity is a marketing figure. The Miami's internal width is 1.32 metres and its internal depth is 52 cm; the Pacific's internal width is 115 cm. Divide the internal width by the number of adults you actually plan to bathe with, and think about whether that works for you.

Step 3: Understand heater size and heating time

Plug-in (13 amp) hot tubs typically have their heater capped at around 2 kW, according to one UK retailer guide. A larger heater heats faster; a smaller one draws less power but takes longer.

The Miami owner manual gives heating times to reach 40°C: 16 to 24 hours from 10°C, 12 to 20 hours from 15°C, and 10 to 18 hours from 20°C, with the cover on. Decathlon's listing for the same tub quotes roughly 2°C per hour. Whatever the headline claim, plan on filling the tub at least a day before you want to use it, particularly in spring and autumn.

Some manufacturers make efficiency claims, for example that certain ranges are "up to 56.6% more energy-efficient than standard inflatable models". The page making that claim did not say which models or what the comparison was, so treat it as a prompt to ask for the wattage and the heating-time table rather than as a spec.

Step 4: Check where the power will come from

This is where small gardens catch people out, because the socket location and the cable length interact:

• The Miami manual says to plug directly into a grounded socket, not an extension lead or multi-plug adapter, and that the outlet should be at least 4 metres from the spa.
• The Miami's listed cable is 7 metres. So the socket needs to sit somewhere between 4 metres and (allowing for routing) well under 7 metres from the tub, measured along the cable path.
• The manual calls for protection by an RCD rated at 30 mA or less, and says the plug must stay accessible after installation.
• If you have no suitable outdoor socket, one retailer guide estimates £150 to £450 to install one; Lay-Z-Spa's own comparison page quotes £130 to £200 for fitting an external plug. Prices vary by location and the route the cable has to take.

The installation must be safe and adequate, carried out by a registered competent person, according to the Planning Portal's guidance on hot tub electrics. Use a qualified electrician for any new outdoor socket.

Step 5: Check the ground

Do not leave this until delivery day. The Miami manual says the surface must be flat, level and able to bear the weight of the spa, water and bathers. It recommends grass and concrete and does not recommend dirt, sand, gravel, decks, balconies, driveways or soft soil. It also recommends an insulating mat underneath and siting the tub near a drain. A filled 669 litre tub with four adults weighs roughly a tonne; our base and placement guide shows the calculation.

Step 6: Think about running costs before you choose

A heater drawing 2 kW costs a little over 50p for every hour it runs at the current price cap, so the heater size and how well the tub holds its heat matter more than the purchase price over a season. See our running costs guide for the full calculation.

Small garden checklist

1. Measure the width including the pump unit, and add 1 metre clearance on every side.
2. Check the tub's external height against any fence, wall or overhang.
3. Find the socket position and measure the cable route. The Miami manual wants the socket at least 4 metres away, yet it must still be within the cable's reach. Check the manual for your model.
4. Confirm the ground: flat, level, grass or concrete, with an insulating mat.
5. Note the heater wattage and the heating-time table, not just the marketing claim.
6. Check the internal width against the number of adults you will bathe with.
7. Check the tub's water volume (and think about where 650 to 700 litres will drain).

Frequently asked questions

What size inflatable hot tub is best for a small garden?

There is no single best size, but the compact range runs from about 155 cm to 180 cm external width. Add the pump unit and a metre of clearance on each side before deciding whether a model fits.

Can I put an inflatable hot tub on a patio?

Often yes, but follow your manual. One UK retailer says most patios and block paving are already reinforced and can usually take a hot tub's weight, provided the surface is level and drains well, and advises asking a specialist if unsure. The Lay-Z-Spa manual recommends grass and concrete and does not recommend decks, gravel or driveways.

Do I need planning permission?

The Planning Portal says you typically will not need planning permission to install a hot tub in your garden, but you may if you live in a listed building or conservation area, so check with your local authority.

Can I use an extension lead?

The Lay-Z-Spa manual says no: plug directly into a grounded socket. Ask an electrician to fit a socket in the right place instead.

Related guides: inflatable vs hard-shell hot tub and hot tub base and placement.

Sources (checked 12 November 2026)

• Bestway Lay-Z-Spa Miami AirJet product page (water volume, size, power, cable): bestwaystore.co.uk
• Bestway Lay-Z-Spa Miami owner manual (heater, heating times, RCD, socket distance, ground guidance): manuals.plus
• Lay-Z-Spa, best hot tubs for small spaces (clearance guidance, efficiency claim): lay-z-spa.co.uk
• Lay-Z-Spa vs hard shell hot tubs (external plug cost): lay-z-spa.co.uk
• Decathlon UK, Lay-Z-Spa Miami listing (internal dimensions, heating rate): decathlon.co.uk
• Wave Spas, The Pacific (dimensions, heater): waveglobal.zendesk.com
• MSpa specification compilation (Tekapo, Bergen): manuals.plus
• Happy Hot Tubs, 13 amp vs 32 amp (socket installation estimate, 2 kW limit): happyhottubs.co.uk
• Happy Hot Tubs, best base for a hot tub (patios and paving): happyhottubs.co.uk
• Planning Portal, hot tub permissions: planningportal.co.uk