Home Heat Pump Guide

Export Tariff and Heat Pumps: Using Solar Surplus

By Home Heat Pump Guide
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 15-24p — but exporting it earns only 4-15p. 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

15-24p/kWh saved

Export Income

4-15p/kWh earned

Ratio

2-3x better to use it

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

SupplierExport RateNotes
Octopus (Outgoing)Up to 15p/kWhVariable rates, can be very competitive
EDF~5-7p/kWhStandard SEG rate
British Gas~4-5p/kWhMinimum SEG rate
E.ON~5-6p/kWhStandard SEG rate

Export rates as of Q1 2026. Octopus offers the most competitive export tariffs for solar panel owners.

For surplus you genuinely cannot use, Octopus export rates are the best available. 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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See combined heat pump + solar + export income figures

Frequently Asked Questions

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

Always better to use it. Self-consumption saves 15-24p/kWh versus 4-15p/kWh from export. 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, typically 4-15p/kWh. Octopus offers the best 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.