Getting paid, and getting more

Adding a battery to a builder-fitted system

Short answer

A battery can often be added to builder-fitted solar, but first identify who owns the system, the inverter model, network approval and warranty conditions. Size storage from measured solar surplus and out-of-solar-hours use. Do not assume the developer’s array size proves a particular battery will be worthwhile.

Check first
Ownership and inverter model
Size from
Measured surplus and demand
Ask
AC or DC coupled
Confirm
Warranty and DNO paperwork
By the UKSolars editorial team Updated 2026-09-09
Sources checked 2026-09-09

Start with evidence from the house

Use solar monitoring and smart-meter data to compare midday export with evening demand. A new home’s heat pump, EV charger and occupancy pattern can make generic battery rules unreliable.

Questions for the quote

  • Is the design AC- or DC-coupled?
  • What are the usable capacity and charge/discharge power?
  • Which circuits work in an outage, if any?
  • Does work touch anything covered by the developer or structural warranty?
  • Who updates the network connection and export supplier?
  • What does the warranty cover: years, cycles, throughput, capacity and labour?

Fix the export tariff first

If the home is exporting without payment, set up the export tariff before using a poor or missing rate to justify battery spending.

Then use the battery sizing method and compare the installed price with the value it can realistically shift.

Common questions

Will adding a battery affect a new-home warranty?
Warranty terms differ. Obtain written confirmation from the warranty provider or developer where work could affect covered fabric, wiring or equipment; do not rely on a battery installer’s general assurance.
Must the existing solar inverter be replaced?
Not necessarily. An AC-coupled system has its own inverter, while a DC-coupled design may use or replace a compatible hybrid inverter. Ask for the proposed arrangement in writing.

Sources

Checked 2026-09-09. Rates, rules and eligibility can change. Confirm current terms before signing a contract or applying for funding.

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