The Hidden First Bill: Part P, Dedicated Circuits and Why an Electric Sauna Needs an Electrician

Installing an electric sauna in the UK triggers Building Regulations approval (Part P) in almost every situation. You'll need a registered electrician to design and sign off the work, costing £800–£1,500 in labour and compliance alone—often before you buy the heater itself. Electrician quotes of £200–£400 for site visits and quotes surprise buyers when they're researching costs. The only genuine way to avoid it: choose a gas heater powered by propane, which needs neither electricity nor an electrician. For electric buyers who proceed, understanding Part P upfront saves frustration and hidden bills later.

What is Part P, exactly?

Part P is Building Regulations for electrical installations in domestic property. Any permanent electrical work—including sauna heaters—must be designed and certified by a qualified electrician registered with a competent-person scheme (such as NAPIT, ELECSA, or NICEIC).

The electrician must carry out an Electrical Installation Condition Report (EICR) on your existing supply, confirm it can handle the new load, design a dedicated circuit, and issue a completion certificate within 30 days. The local authority can request the certificate; failure to obtain one risks a fine (£5,000+) and invalidity for insurance claims.

According to Building Regulations guidance, permanent electrical appliances in wet areas require added protection: a residual current device (RCD) rated 30 mA and Type A (AC + DC). Sauna cabins count as wet areas—water runs over you and condensation is inevitable.

Why a dedicated circuit?

Electric saunas draw serious power. A typical 6 kW heater needs 26 amps; an 8 kW heater needs 35 amps. Most UK homes run lights, sockets and appliances on 16 amp or 20 amp circuits, designed to share. A sauna heater cannot share a circuit—it has its own breaker and wiring all the way from the consumer unit.

If your property has an older 60 amp or 80 amp main fuse (common in 1980s properties), the entire supply may struggle to deliver 35 amps continuously to one appliance while the rest of the house runs normally. An upgrade to the consumer unit costs £1,200–£2,000.

This is why electricians quote £200–£400 for a site visit and desktop survey before giving a final price. They need to inspect your existing board, test the supply, and model the load flow.

The total cost breakdown

A typical electric sauna installation runs:

• Electrician's survey and design: £200–£400
• New circuit (cable, breaker, RCD, installation): £400–£800
• Consumer unit upgrade (if needed): £1,200–£2,000
• Building Control sign-off (some local authorities): £150–£300
• Total non-heater cost: £800–£1,500 (simple) to £3,500+ (if upgrades needed)

The heater itself is extra. For a 6–8 kW electric heater, expect £800–£2,000 retail. You're looking at £1,600–£3,500 before you heat a single session.

Gas heaters, by contrast, arrive ready to use. No wiring, no Building Regulations, no electrician.

Is there a way around Part P?

Technically, no—not legally. Every permanent electrical installation in the home needs certification. However, some users explore temporary or portable electric heaters (under 2 kW), which sidestep some requirements because they plug into a standard socket.

These trade-off power for simplicity. A 2 kW heater warms a small (up to 3 m³) sauna slowly, taking 45–60 minutes to reach 70°C. They're also inefficient, losing heat through the tent fabric.

If convenience and low installation cost drive your choice, a gas sauna heater delivers far more practical advantages: ready to go, no electrician, full power, and genuine portability.

What does the electrician actually do?

A qualified electrician will:

• Test your earth bonding and supply voltage
• Calculate load capacity (can your main fuse handle a 35 amp draw?)
• Design the circuit: cable gauge (typically 6 mm² or larger), breaker rating, RCD type
• Run cable from consumer unit to sauna location (may require conduit, especially in gardens)
• Install the breaker, isolator switch, and 30 mA Type A RCD
• Certify the work and lodge it with Building Control (usually)

The entire process takes 2–4 weeks from survey to completion certificate, because Building Control typically reviews designs and inspects before issuing approval.

Gas appliances are tested and CE-certified in the factory. Once installed, they're ready: no sign-offs, no inspectors, no delays.

Comparing the hidden costs

An electric sauna buyer pays for the heater, plus £800–£1,500 in electrical compliance. A gas buyer pays for the heater, plus a regulator kit (£89) and a propane bottle (£50–£80 initially).

The gas running cost is roughly level with electric at current UK rates: £2–£3 per session, either way. The real advantage of gas isn't cutting bills—it's removing the electrician, the wiring, the wait, and the compliance headache entirely.

For rural properties, allotments, or gardens far from the house, gas is even more compelling: no trenching for cable, no upgrading the main supply, no months of delay.

The honest case for electric

Electric saunas do offer one genuine advantage: no combustion. Some users simply prefer the idea of electricity (even if more complex to arrange) than managing propane bottles. They also suit urban flats where external venting isn't an option.

If you're committed to electric, budget for the full £1,600–£3,500 upfront and find a registered electrician before you buy the heater. Get the quote in writing, confirm the consumer unit survey is included, and ask about your local authority's Building Control review fee.

The hidden bill isn't hidden if you're expecting it.

Sources

Building Regulations Part P (Department for Levelling Up, Housing and Communities, 2024); competent-person scheme requirements (NAPIT, ELECSA guidance, July 2026); typical UK electrician labour rates and RCD Type A/AC specifications (Electrical Safety Foundation International, 2025).