One in three EPC-certificated homes in Windsor’s SL4 district is a flat. That fact shapes the battery conversation here more than any roof does. Of 13,517 certificated homes, roughly 59% are houses, 33% flats, 4.4% bungalows and 3.9% maisonettes, according to the EPC register as summarised by EPC Advisor. The usual installer picture of a semi with a garage covers some of them. It leaves a lot of Windsor out.
This guide goes through each type of home in turn: where a battery can physically go, and who has to agree before it does. For the rest of the battery decision, including size, cost and the local network, see our Windsor battery storage guide.
Houses: the wall next to the consumer unit
In most houses the battery goes on a wall, close to the consumer unit, with clear space around it for ventilation and servicing. In practice that means:
- A garage. This is the easiest case. It is out of the living space and there is usually a short cable run to the meter. With about 5,973 privately kept plug-in vehicles across Windsor and Maidenhead at the end of June 2026, up from 4,651 a year earlier, a garage is also the natural place for an EV charger, so it is worth planning the two together.
- A utility room or under-stairs cupboard. These are common in terraces and older semis. The survey checks the wall and whether the space meets the manufacturer’s installation rules.
- A loft. Sometimes possible, but access, temperature and weight all need checking. It is rarely the first choice.
Windsor’s houses also carry efficiency headroom. SL4 averages EPC band D, only 44% of certificated homes reach band C or above, and solar PV is the improvement most often recommended on local certificates, appearing 11,356 times. Where panels make sense, a battery is usually fitted at the same visit, which the Energy Saving Trust says costs less than a separate visit later.
Flats and maisonettes: consent first, then space
The flat share of 33%, plus 3.9% maisonettes, is high for a Berkshire town. Three points decide whether a battery is possible:
- Consent. A leaseholder normally needs the freeholder’s or management company’s agreement for fixed equipment and new cabling, and a tenant needs the landlord’s. Ask before you pay for a survey.
- Panels. A flat roof is shared, so panels may not be on the table at all. A battery does not need them. It can be charged from the grid on a time-of-use tariff and used at the evening peak. Our guide to battery storage without solar panels covers when that pays.
- Space. A flat often has no garage, so the question becomes whether a hallway cupboard, utility space or storeroom meets the manufacturer’s installation rules. Some won’t, and a survey should say so.
Maisonettes often have more room than a flat, and sometimes a private entrance, but the lease still applies.
Bungalows: one floor, one roof
Bungalows are 4.4% of SL4’s certificated homes. They usually offer the shortest cable runs in the district: panels, consumer unit and battery are all on one level. Because the whole footprint is roof, a bungalow can carry an array that makes a bigger June surplus than the household can use. That is where a battery adds most. Size it to your evenings rather than to the roof. Our guide to what size home battery you need shows how.
Renters: a growing share of conversations
At the 2021 Census, 66.2% of Windsor and Maidenhead households owned their home, down from 68.0% in 2011. Private renting rose 4.4 percentage points to 20.6%. For a fifth of households, then, the first conversation is with a landlord. A battery is fixed equipment, and the agreement should be in writing.
Inside the conservation areas
The Royal Borough has 27 conservation areas. Several cover Windsor itself: the Town Centre (with sub-areas including Castle and Royal Mews, Historic Core and High Street, and Riverside), Inner Windsor, Trinity Place/Clarence Crescent, Mill Lane in Clewer Village, and Old Windsor. An Article 4 Direction in the town centre requires planning approval even for exterior painting.
For a battery, that points one way: keep the unit and its cabling inside. If anything must go on an outside wall in the centre, check with the council first. Listed buildings need consent for works that affect their character, and that can include work inside. Windsor Castle took its first solar panels in 2024, on the roof of the Lord Chamberlain’s Upper Store, so careful design can work on sensitive buildings. The consent process still applies to your own address.
The grid and backup
Windsor is on SSEN Distribution’s Southern Electric Power Distribution network. A system whose inverters, including the battery’s, total up to 16 A (3.68 kW) per phase is notified under G98. Anything larger needs a G99 approval before work starts. In every type of home, a standard grid-tied battery shuts down in a power cut unless backup has been designed and installed.
For panels, our solar panels Windsor page covers SL4 roofs and Switch Together. For the county view, see solar panels in Berkshire.
Sources: EPC Advisor, SL4 Windsor and Maidenhead (government EPC register data); ONS Census 2021, tenure (Windsor and Maidenhead); Royal Borough of Windsor and Maidenhead, Conservation areas and Permitted development rights; DfT and DVLA, VEH0142 (2026 Q2, published 23 September 2026); Energy Saving Trust, Battery storage (updated 19 August 2026); Reuters, reporting the Sovereign Grant annual report (July 2024); NESO, GB DNO licence area boundaries; SSEN, Who we are; ENA EREC G98 Issue 2.