400 kW Solar + Heat Pump Pool Electrification at a Surrey Destination Spa

The hotel

An 80-room independent destination spa resort in the Surrey Hills with 25m pool, full spa with 14 treatment rooms, fitness suite, 90-cover restaurant, and substantial corporate-events and wedding business. AONB designation. Listed Grade II main house plus extensive unlisted estate buildings. Annual energy spend £290,000 (£195,000 electricity + £95,000 gas).

The brief

Combined electrification programme: replace existing gas pool heater with air-source heat pump, deploy estate-distributed solar, eliminate Scope 1 emissions from the property, and underpin the destination spa sustainability marketing narrative for the wellness-retreat segment.

What we delivered

400 kW estate-distributed solar array: 220 kW on the main spa block flat roof (unlisted), 110 kW on the stable-block roof, 70 kW on the function-suite extension. Air-source heat pump conversion of the pool plant (180 kW thermal capacity). Listed Building Consent secured for the stable-block roof — Grade II main house untouched. Combined capex £620,000 with AIA 100% first-year tax relief on the full amount.

The numbers at year one

• Annual solar generation: 375,000 kWh
• Self-consumption: 94% (pool plant + spa plant electric load absorbing solar generation)
• Year-1 combined saving: £135,000 (£105,000 electricity offset + £30,000 net gas-to-electric conversion saving)
• Capex: £620,000 gross; £465,000 after AIA + 50% FYA shield
• Effective payback: 3.4 years
• Scope 1 emissions reduced by 168 tonnes CO2e/year (gas pool plant eliminated)
• Wellness-retreat segment booking-rate uplift 16% in 6 months following lobby display deployment

What the client said

“The combined electrification project worked because they understood both the solar economics and the heat pump conversion. The Scope 1 reduction lets us claim genuine net-zero pool operation in our wellness marketing — and the wellness-retreat booking-rate uplift more than covers the marginal heat pump capex.”