Export Tariff and Heat Pumps: Using Solar Surplus

Q: Is it better to use solar surplus for my heat pump or export it?

Usually better to use it. Each kWh you use yourself saves what you would have paid to import it (the price cap rate is 26.32p per kWh for 1 October 2026 to 31 December 2026), whereas export tariffs usually pay considerably less per kWh. Check your own import and export rates to compare.

Q: How can I divert surplus solar to my heat pump?

Use a solar diverter (like MyEnergi Eddi) to automatically send surplus solar to your hot water cylinder via the immersion heater. Alternatively, schedule your heat pump to heat water during peak solar hours. Smart systems can automate this.

Q: What is the Smart Export Guarantee rate?

Smart Export Guarantee rates vary by supplier and change often, so check each supplier's current export rates. Export rates are usually well below what you save by using the electricity yourself.

Q: Can I have an export tariff and a heat pump tariff simultaneously?

Yes. Your import tariff (e.g., Octopus Cosy) and export tariff (e.g., Outgoing Octopus) are separate products that work together. You pay cheap off-peak rates for overnight heating and get paid for surplus daytime solar export.

By Home Heat Pump Guide Published 18 March 2026

UK home with solar panels generating surplus electricity that can power the heat pump or be exported for income — Surplus solar electricity is worth 2-3 times more powering your heat pump than earning export income.

Every kWh of surplus solar you use for your heat pump saves you what you would have paid to import it (up to 26.32p at the price cap) — but exporting it usually earns considerably less. The smart strategy is to maximise self-consumption first (using surplus solar to heat water or pre-heat your home) and only export what you genuinely cannot use.

This guide explains how to combine solar panels, a heat pump, and an export tariff for maximum financial benefit.

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Self-Consumption vs Export

Self-Consumption Value

Your import rate saved (price cap: 26.32p/kWh)

Export Income

Your export rate earned (varies by supplier)

Rule of Thumb

Use it if your import rate is higher than your export rate

Diversion Strategies

Solar diverter (e.g., MyEnergi Eddi): Automatically sends surplus solar to your immersion heater, heating water for free
Schedule heat pump hot water during solar hours: Set your heat pump to heat the cylinder 11am-3pm when solar peaks
Pre-heat house during solar generation: On mild days, use surplus solar to warm the house slightly above target — free stored heat
Smart integration: Some systems automatically adjust heat pump operation based on solar generation

Hot water cylinder being heated by surplus solar electricity diverted from solar panels through heat pump system — Diverting surplus solar to your hot water cylinder is the simplest and most effective self-consumption strategy.

Export Tariff Rates

Supplier	Export Rate	Notes
Octopus (Outgoing)	Fixed or variable export options	Check current rates
EDF	Smart Export Guarantee tariff	Check current rates
British Gas	Smart Export Guarantee tariff	Check current rates
E.ON	Smart Export Guarantee tariff	Check current rates

Export rates differ widely between suppliers and change often, and some require you to take their import tariff: check the supplier's current rates for solar panel owners. Last reviewed October 2026.

For surplus you genuinely cannot use, compare suppliers' current export rates. Combined with Octopus Cosy for import, you get the best of both worlds: cheap overnight heating plus competitive export income.

Smart meter showing solar generation and export data alongside heat pump consumption — Your smart meter tracks both what you import and export — the data helps optimise your self-consumption strategy.

Energy bill showing reduced costs from combining solar self-consumption with heat pump and export tariff income — The combined strategy of self-consumption + export income + off-peak tariff delivers the lowest possible bills.

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Frequently Asked Questions

Is it better to use solar surplus for my heat pump or export it?

Usually better to use it. Self-consumption saves your import rate (up to 26.32p/kWh at the price cap), and export usually pays considerably less. See our solar + heat pump guide.

How can I divert surplus solar to my heat pump?

Use a solar diverter (MyEnergi Eddi) or schedule your heat pump to heat water during peak solar hours.

What is the Smart Export Guarantee rate?

SEG rates vary by supplier and change often, so check current export rates. See the Home Solar Guide for details.

Can I have an export tariff and a heat pump tariff simultaneously?

Yes. Your import tariff (e.g., Cosy) and export tariff are separate products that work together.

Solar Export and Heat Pump Economics

Combining solar panels, a heat pump, and smart tariffs creates an integrated energy system where every kWh is optimised. The Boiler Upgrade Scheme and zero-VAT solar make the combined investment increasingly accessible. With proper insulation and the right tariff strategy, UK homeowners can achieve annual heating costs below £400 while earning export income from surplus generation.