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London & South-East England

Home Battery Storage

Store cheap overnight power or your own solar surplus, and stop buying electricity at the daytime rate.

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Accredited, certified installersOne point of contactFixed written quote

Is battery storage right for your home?

  • Homes with solar panels that export most of their daytime generation
  • Households out during the day whose use peaks in the evening
  • Homes on, or moving to, a cheap overnight time of use tariff
  • Owners with an electric car or heat pump, or planning one
  • Homes that want to keep the lights and router on during a power cut

Home Battery Storage: key facts

  • A home battery stores surplus solar or cheap overnight electricity and releases it when the tariff is dear.
  • Typical home batteries hold 5 to 13.5 kWh; an average UK home uses around 7 to 8 kWh of electricity a day.
  • Indicative cost: 5 kWh £3,000 to £4,500, 10 kWh £4,500 to £7,000, 13.5 kWh £6,000 to £8,500 installed.
  • Charged at 0% VAT until 31 March 2027, whether the battery is fitted with solar or on its own.
  • Most batteries are warranted for around 10 years or about 6,000 charge cycles, whichever comes first.
  • Installed by accredited, MCS certified installers, arranged and project-managed by Stay Warm.

What is battery storage?

A home battery is a lithium battery pack, usually lithium iron phosphate, with an inverter that charges it and discharges it into the house. It fills up either from your solar panels during the day or from the grid overnight on a cheap time of use tariff, and it powers the home in the evening when electricity is at its most expensive. A 5 kWh unit is about the size of a small suitcase; a 13.5 kWh unit is nearer a large radiator. Most homes fit one in a garage, a utility room or a cupboard under the stairs.

London and South-East homes have some of the highest electricity use in the country, with many households out during the day and using most of their power between five and ten in the evening. That is exactly the pattern a battery suits: without one, a solar system exports most of what it makes for a low export price and buys it back at night for three or four times as much. A battery also lets a home without solar shift its use onto an overnight tariff, which matters more once an electric car or a heat pump is added.

We are an insulation company first, so our advice is to cut the heat you lose before you spend on storing energy. Once the fabric is right, Stay Warm surveys the electrical supply, the space available and your tariff and use pattern, then gives you one fixed quote. An accredited, MCS certified installer fits and commissions the battery. Where we are already fitting solar or insulation, doing the battery in the same project keeps the cost down.

Who does the work

Home battery storage is arranged and project-managed by Stay Warm and installed by accredited, MCS certified installers. You get one point of contact, one written quote and one guarantee pack.

Home Battery Storage cost guide

Indicative 2026 market ranges for London and the South-East. Your fixed quote follows a free survey and depends on capacity, whether the battery is AC or DC coupled, and where it sits.

Job typeIndicative cost
5 kWh battery, AC coupled£3,000 – £4,500
10 kWh battery£4,500 – £7,000
13.5 kWh battery£6,000 – £8,500
Battery fitted with a new solar system£3,000 – £6,000
Backup gateway, consumer unit work, cablingItemised

VAT: 0%. Since 1 February 2024 a home battery counts as an energy-saving material in its own right, whether it is fitted with solar panels or on its own, so the installation is charged at 0% VAT until 31 March 2027 (HMRC VAT Notice 708/6).

What a battery installation includes

Lithium iron phosphate battery module, 5 to 13.5 kWh, expandable on most systems
Battery inverter (AC coupled) or hybrid inverter shared with solar (DC coupled)
Wall or floor mounting in a garage, utility room or cupboard, with the clearances the manufacturer needs
Consumer unit work, isolators and a CT clamp on the incoming supply
Optional backup gateway so chosen circuits stay live in a power cut
MCS certificate, DNO notification and a monitoring app for charge, discharge and export

How battery installation works

1

Free survey

We check the fuse board, the incoming supply, where the battery can go and how you use electricity, including any solar, EV or heat pump.

2

Sizing and fixed quote

A recommended capacity and coupling method with a fixed written quote, usually within a few days.

3

Installation

An accredited, MCS certified installer mounts the battery and inverter and wires them in, normally in one day.

4

Commissioning and paperwork

The system is tested, the tariff schedule is set up in the app, and you receive the MCS certificate, DNO notification and warranties.

Free survey & fixed quote

Book a free, no-obligation survey and we will send a clear, fixed written quote. One point of contact from survey to sign-off, and a written guarantee on the work.

Get a free quote

Home Battery Storage FAQs

How much does a home battery cost?
Indicative 2026 ranges are £3,000 to £4,500 for 5 kWh, £4,500 to £7,000 for 10 kWh and £6,000 to £8,500 for 13.5 kWh, installed. A battery fitted at the same time as a new solar system is usually cheaper because it shares the inverter and the visit. VAT is 0% until 31 March 2027.
What size battery do I need?
Enough to cover the evening and overnight use you would otherwise buy at the day rate. For many 3-bed homes that is 8 to 10 kWh. A home with an electric car or heat pump often goes to 13.5 kWh or two modules. We size it on the survey from your bills and your solar output, if you have it.
AC coupled or DC coupled: which is better?
DC coupled means one hybrid inverter runs both the solar and the battery, which is neater and slightly more efficient when both are fitted at once. AC coupled means the battery has its own inverter, which is the usual choice when adding a battery to an existing solar system or fitting one without solar.
Is a battery worth it without solar panels?
It can be, if you use a cheap overnight tariff. The battery charges at the night rate and runs the house during the day and evening at the higher rate. The saving depends on the gap between the two rates and how much electricity you use, so we work it through with you on the survey before recommending one.
Will it keep the power on in a power cut?
Only if a backup gateway or a battery with an emergency power supply output is fitted, and only for the circuits wired to it. A standard grid-tied battery shuts down in a power cut for safety. Backup is an option we itemise on the quote, and it is most useful for the fridge, freezer, lighting and router.
Where can the battery go?
A garage, utility room, hallway cupboard or an outside wall in a weatherproof unit are the usual places. Lofts are possible with care over weight, temperature and access, and some manufacturers exclude them. Who installs it is an accredited, MCS certified installer; Stay Warm arranges and manages the job.

Areas we cover

We arrange battery storage across Greater London, Surrey, Kent and Hertfordshire. See all areas we cover →

Related services

Solar PanelsAir Source Heat PumpsEV Charger InstallationFree Heat Loss SurveyDouble & Triple Glazing

Related guides

In-depth, independent guidance to help you decide.

Is a home battery worth it?Solar and battery grants 2026Where homes lose heatInsulation cost guideLoft insulation guide

Last reviewed September 2026 by Stay Warm Insulation.

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