NOTE Nº 0210 · REV B

Hot Tubs: Cost & Running Costs

Rigid hot tubs cost £2,500–£20,000 and inflatables from about £300 in 2026; UK electricity runs £45–£140 a month depending on insulation and use.

By The Renovation Notes Team · 7 min read · Published 29 September 2025 · updated within the last month · Sources checked 30 September 2026

Explore a serene outdoor patio featuring a luxurious hot tub overlooking a tranquil lake.

In short

A mid-range 5–6 person hot tub costs £5,000–£10,000 to buy, before installation; a full-foam mid-range spa typically costs £50–£90 a month in electricity plus £25–£45 in chemicals. Well-insulated units with full foam insulation cost significantly less to run than entry-level models.

A hot tub is one of the larger discretionary garden purchases a UK homeowner can make, not just because of the purchase price, but because the ongoing running costs are often underestimated at the point of buying. A well-insulated acrylic spa used three or four times a week can add £50–£90 per month to your electricity bill; a poorly insulated entry-level unit running at 40°C through a British winter can push that figure considerably higher.

Types of Hot Tub

Inflatable hot tubs have transformed the entry-level market. Prices start at around £300 for a four-person unit. They are lightweight, easy to store in winter, and require only a standard 13 A socket. The trade-off is that they heat slowly (often the best part of a day from cold), are not as well-insulated as rigid spas, and have a shorter lifespan, typically a few years even with careful use.

Acrylic/rotational-moulded rigid spas are the mainstream choice, ranging from four-person entry models at £2,500–£4,500 to premium eight-person models at £10,000–£20,000. They heat faster, retain heat far better due to full-foam or partial-foam insulation, and typically come with a 5–10-year shell warranty.

Wooden hot tubs, typically cedar or larch, appeal for their aesthetics. Prices run £2,000–£8,000. Many are heated by a wood-fired stove, either inside the tub or alongside it, with at most a small electric circulation pump, making running costs very low once up to temperature. The downside is slow heating (typically a few hours), often no filtration system, and higher maintenance.

Swim spas combine a hot tub section with a resistance swimming current. Prices run from around £10,000 to £35,000 or more for top-specification units. They require a larger footprint (typically 5–6 m long) and more substantial electrical supply.

2026 UK Purchase Costs

Type	Typical price range (inc. VAT)
Inflatable hot tub (4–6 person)	£300–£900
Entry-level rigid spa (4 person)	£2,500–£4,500
Mid-range rigid spa (5–6 person)	£5,000–£10,000
Premium rigid spa (6–8 person)	£10,000–£20,000
Wooden hot tub (cedar, wood-fired)	£2,000–£8,000
Swim spa (5–6 m)	£10,000–£35,000

These prices are for supply only. Installation adds cost depending on what is required.

Installation Costs

Item	Cost range
Concrete pad (standard 2.5×2.5 m, 100 mm)	£600–£1,200
Reinforced concrete pad (heavy spa)	£900–£1,800
Decking platform (pressure-treated timber)	£800–£2,500
Electrical supply (32 A circuit from consumer unit)	£600–£1,200
Crane lift over house (if access is restricted)	£400–£800
Delivery and positioning (typical)	£100–£300

Most rigid spas need a dedicated circuit, commonly 32 A (larger units and swim spas may need more), and installing a new circuit is notifiable work under Part P of the Building Regulations.¹ Inflatable tubs typically run from a standard 13 A socket, though the socket should be RCD-protected and ideally on a dedicated circuit.

A concrete or paving slab base is essential, the manufacturer’s warranty is usually void if the tub is sited on soft or uneven ground. A 2.4×2.4 m spa filled with water and six adults weighs approximately 2–3 tonnes.

Monthly Running Costs

The biggest ongoing expense is electricity. The figures here use the Ofgem price cap electricity rate of 26.32p/kWh for 1 October to 31 December 2026.²

Tub type	Insulation quality	Monthly electricity	Monthly chemicals	Total per month
Inflatable (4-person)	Poor	£80–£140	£20–£35	£100–£175
Entry rigid (4-person)	Partial foam	£60–£110	£20–£40	£80–£150
Mid-range rigid (5–6 person)	Full foam	£50–£90	£25–£45	£75–£135
Premium rigid (6–8 person)	Full foam + insulated cover	£45–£80	£30–£50	£75–£130
Wooden (wood-fired)	N/A	£5–£15 (pump only)	£20–£35	£25–£50

Heat retention is the single biggest variable. A full-foam-insulated spa with a well-fitting hard cover typically uses 3–5 kWh per day to maintain 38°C in winter, roughly £24–£39 per month at that rate. A poorly insulated unit under the same conditions can use 8–12 kWh per day, £63–£95 per month just on standby heating.

Tips for reducing running costs:

Keep the cover on whenever the tub is not in use: much of the heat is lost through the water surface
Lower the temperature to 36°C rather than 40°C when the tub will be unused for several days; a lower set point reduces standing heat loss
Run filtration cycles during off-peak Economy 7 hours if you have that tariff
Check the cover regularly and replace it when it becomes waterlogged, typically every 5–7 years: a waterlogged cover insulates far less effectively
Add a floating thermal blanket (£30–£80) to reduce surface heat loss further

Planning Permission

Hot tubs in rear gardens generally fall under Permitted Development in England and do not need planning permission.³ Check if your property is in a conservation area or if your PD rights have been removed via an Article 4 Direction.⁴ Class E does not cover a verandah, balcony or raised platform, and a platform counts as raised once it is more than 0.3 metres high, so a tall deck built around a tub may need planning permission.⁵³

Part P of the Building Regulations applies to electrical work in a garden where the supply comes from the house.¹ An electrician registered with a competent person scheme can self-certify the work and should give you an electrical installation certificate and a Building Regulations compliance certificate; otherwise the work must be notified to building control before it starts.¹

Maintenance Schedule

Task	Frequency	Annual cost (approx.)
Water chemistry testing and dosing	Weekly	£240–£480 (chemicals)
Filter cartridge cleaning	Monthly	-
Filter cartridge replacement	Every 1–2 years	£40–£150
Full drain and refill	Every 3–4 months	£15–£30 (water)
Hard cover replacement	Every 5–7 years	£300–£700
Annual service (pump, heater, jets check)	Annually	£100–£250

Inflatable vs Rigid Spa: Which Is Right for You?

If you are unsure whether you will use a hot tub regularly, an inflatable model is a sensible first step, the low capital outlay limits your risk. If you use it frequently for 12 months, that is a reasonable signal that a rigid spa will pay for itself in enjoyment and lower per-use cost.

The ongoing running-cost difference between an inflatable and a mid-range rigid spa is often surprisingly small in mild months, but diverges significantly in winter. If you intend to use the tub year-round, the insulation quality of a rigid spa makes it the more economical choice over a three-to-five-year horizon despite the higher upfront cost.

References (5)

Figures in this note were checked against the sources below on 30 September 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

1technicalvery strongMinistry of Housing, Communities and Local Government.RN-JYJ3I5The document that decides what electrical work a homeowner may legally do themselves, and the exact list of notifiable jobs. Regulation 12(6A), reproduced at paragraph 2.5, makes only three things notifiable: the installation of a new circuit, the replacement of a consumer unit, and any addition or alteration to existing circuits in a special location. Regulation 12(9) defines special location as, in a room containing a bath or shower, the zone extending vertically from finished floor level to 2.25 metres (or the shower head position if higher) and horizontally 600mm from the edge of the bath tub or shower tray. Paragraph 2.7 states that all other electrical installation work is not notifiable, namely additions and alterations to existing installations outside special locations, and replacements, repairs and maintenance anywhere. Paragraph 2.8 gives worked examples: a built-in cooker is not notifiable unless a new cooker circuit is needed, and connecting an electric gate or garage door to an existing isolator is not notifiable but running a new circuit from the consumer unit to that isolator is. Paragraph 2.2 confirms Part P reaches outdoor work including fixed garden lighting, pond pumps and outbuildings such as sheds, detached garages and domestic greenhouses. Notifiable work must be certified by self-certification by a registered competent person, third-party certification, or a building control body (paragraph 3.1), with the compliance certificate issued within 30 days (paragraph 3.4). Note that Approved Document P is a source of guidance rather than a ban: non-notifiable work still has to comply with BS 7671.
2technicalvery strongOfgem.RN-YYE8U2The live source for any running-cost sum in a heating note. For 1 October to 31 December 2026 the direct debit cap is 26.32p per kWh for electricity with a 54.83p daily standing charge, and 7.97p per kWh for gas with a 29.68p daily standing charge, giving a typical annual dual fuel bill of £1,723, a 4% rise on the previous period. Ofgem states these are the average unit rate and standing charge for direct debit customers in England, Scotland and Wales; gas prices include 5% VAT while electricity carried no VAT in this period. The cap is reset every three months, so any note quoting a pence-per-kWh figure should be dated against this page.
3technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-J6L7TIThe primary legal text for garden rooms, sheds, summerhouses, pergolas, greenhouses and outdoor pools. Class E permits any building or enclosure, swimming or other pool within the curtilage required for a purpose incidental to the enjoyment of the dwellinghouse, plus a domestic heating oil container. Limitations: E.1(b) buildings, enclosures and containers other than the original dwellinghouse must not cover more than 50% of the curtilage; E.1(c) nothing forward of a wall forming the principal elevation of the original dwellinghouse; E.1(d) single storey only; E.1(e) maximum height 4 metres with a dual-pitched roof, 2.5 metres if any part is within 2 metres of a curtilage boundary, otherwise 3 metres; E.1(f) eaves no higher than 2.5 metres; E.1(g) not within the curtilage of a listed building; E.1(h) no verandah, balcony or raised platform; E.1(j) oil containers capped at 3,500 litres. E.4 defines incidental use as including keeping poultry, bees, pet animals, birds or other livestock for domestic needs or personal enjoyment, which is why a garden room used as a separate dwelling falls outside Class E.
4technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-3LA2VCArticle 4(1) allows the Secretary of State or the local planning authority, where satisfied that it is expedient that development should not be carried out without permission, to direct that the permission granted by article 3 does not apply to all or any development of a Part, Class or paragraph of Schedule 2 in a specified area, or to any particular development. The procedures for making, modifying or cancelling a direction are set out in Schedule 3, and a direction does not affect development for which prior approval was granted before it took effect.
5technicalvery strongThe National Archives, legislation.RN-OWGIY3Schedule 2 Part 1 of the GPDO 2015, development within the curtilage of a dwellinghouse. This is permitted development itself: Class A enlargement and alteration, with the limits and conditions, through the classes covering roof alterations, porches, outbuildings and hard surfaces. Every statement about what can be built without planning permission traces to this Part, and the exclusions at the start of each class are where most projects actually fall out.