Hertfordshire’s housing was planned more deliberately than most counties’. Stevenage was the first new town designated, in November 1946, Hemel Hempstead and Hatfield are new towns too, and Welwyn Garden City and Letchworth were laid out as garden cities with their own rules on what can change outside a house. Alongside them sit owner-occupied market towns full of detached houses and semis, and a southern fringe where flats are a third of the stock. Where solar panels and a battery go depends on which of those four kinds of street you live on. Our hub on solar panels across Hertfordshire covers each council’s grants and planning; this guide takes the houses one type at a time.
A general rule first. In a house with a garage or side passage, a battery usually goes in the garage, a utility room or on a side wall near the meter, where the cable run to the consumer unit is short. A loft is a fallback, used only where the manufacturer’s instructions allow it and an engineer can reach the unit for servicing. The panels go where the roof faces best, unless something says otherwise. In Hertfordshire, something often does.
The new towns: long terrace roofs
Terraces are the defining house of the new towns. In Stevenage’s built-up area 44.9% of households live in terraced houses, in Welwyn Garden City 37.4%, across Hemel Hempstead’s 13 wards 34.8% and across Hatfield’s four wards 33.4% (the last two our sums of ONS ward figures). A terrace roof is long and plain, which suits an orderly array, but each house controls only its own slice, so arrays are often smaller than the 4.5 kWp the Energy Saving Trust treats as typical.
The battery is the harder part. Mid-terrace houses rarely have side access, so the unit usually goes indoors, in a cupboard or utility space near the consumer unit. Efficiency is middling rather than poor: ONS puts the median terrace in Stevenage and in Dacorum at an EPC score of 69, the bottom of band C. Our page on solar panels in Stevenage covers the town’s housing and council grant in full.
Ownership matters as much as layout. In Stevenage’s built-up area 25.3% of households rent from a social landlord, and 20.4% of the borough’s households rent from the council itself; across Hemel Hempstead’s wards the social-rented share is 26.7%, and across Hatfield’s 27.5%. For those households the roof is the landlord’s decision.
The garden cities: a second gatekeeper
In Welwyn Garden City and Letchworth, planning permission is not the only consent. Welwyn Hatfield Borough Council’s Estate Management Scheme covers most of Welwyn Garden City, including most homes in Sherrards and Handside wards, and the council describes it as entirely separate from the planning system. It grants consent for panels on a rear or side roof slope, leaves a principal slope to the case officer’s judgement and rules out wall-mounted panels in any position. Its fee schedule, updated 1 April 2026, charges nothing for a photovoltaic application but £281 for a retrospective one, so the order of events matters. See solar panels in Welwyn Garden City for the estate’s boundaries.
Letchworth goes further, and it reaches the battery as well as the roof. The Heritage Foundation’s principles, revised in May 2026, divide the town into two areas: in its Heritage Character Area panels must be on rear elevations and not visible from the public realm, while in its Modern Character Area any roof slope is acceptable if the other requirements are met. Its consent also covers battery storage units and other ancillary equipment, which must not be visible from the public realm anywhere. Where one half of a pair of semis already has panels, the Foundation expects the other to mirror them. Leaseholders need consent under their lease as well. Our Letchworth battery storage page covers where a unit can sit out of view, and solar panels in Letchworth Garden City covers the two character areas.
Both garden cities also have large social-rented sectors: 30.8% of Welwyn Garden City’s households and 30.1% of Letchworth’s, against 18.7% across North Hertfordshire.
Detached houses and semis: the owner decides
The market towns and the southern suburbs are a different picture. Across Harpenden’s four wards 39.7% of households live in detached houses and 78.2% own their home (our sums of ward figures); in Bishop’s Stortford’s built-up area 32.6% are detached; Potters Bar is 46.5% semi-detached, rising to 61.6% in Furzefield ward. Across St Albans district 76.5% of households live in houses. In these homes a garage or side wall usually takes the battery, the owner controls the roof, and the survey goes straight to design. Our page on solar panels in Harpenden has the town’s detail.
Two cautions apply. First, efficiency: Watford’s median detached and semi-detached houses both score 63 on their EPC, St Albans’ median semi scores 66, and homes built before 1929 have medians of 61 in St Albans district, 60 in Dacorum and 58 in East Hertfordshire. In an older house, insulation may deserve the first spend. Second, a few streets lose the usual planning freedom: the Cunningham Avenue Article 4 direction in St Albans withdraws the right to install solar PV, and the Bishop’s Stortford Conservation Area direction brings renewable energy equipment on homes into the planning system on all elevations.
Flats: the building owner first
The southern edge of the county is where flats concentrate. Borehamwood’s built-up area is 34% flats, maisonettes or apartments, Hertford’s 30.5%, and Watford has 28.8% of households in purpose-built flats plus 5.5% in converted or shared houses. UK Power Networks says the building owner’s permission is needed before solar or storage work begins on a multi-occupied building. Watford also has the highest private-rented share here, 28.2% of households, and for them the landlord decides.
Sizing, once you know where it goes
Where a battery can physically go often settles its size before any tariff does, especially in a terrace cupboard or a Letchworth utility room. The Energy Saving Trust says there is no exact formula, describes a typical home system as perhaps 10 kWh and puts a 5 kWh system at around £4,600; our guide to what size home battery you need shows how to read the evening figure from your bills. The battery systems in our own job photos are EnSmart and Hanchu. Tell us your town and house type at survey, and whether you are inside an estate scheme, and we will say plainly where everything can go, or whether it can go at all.
Sources: ONS, Towns and cities, characteristics of built-up areas, Census 2021 (tables 1c, 5c and 6c: Stevenage, Welwyn Garden City, Letchworth, Borehamwood, Potters Bar, Hertford, Bishop’s Stortford); ONS Census 2021, TS044 and TS054 by ward and local authority via Nomis and the ONS Census API (Hemel Hempstead, Hatfield, Harpenden and Furzefield wards; St Albans, Watford, Stevenage, North Hertfordshire); ONS, Median energy efficiency score, March 2025 edition (tables 2a to 2c); Welwyn Hatfield Borough Council and wgc-ems.org, Estate Management Scheme policies, design guide and fee structure; Letchworth Garden City Heritage Foundation, Solar Panels Design Principles (revised May 2026); St Albans City and District Council, Cunningham Avenue Article 4 Direction; East Herts District Council, Bishop’s Stortford Article 4 directions; UK Power Networks, Solar and storage: cost, time and what’s involved; Energy Saving Trust, Solar panels and Battery storage. Read 15 October 2026. Ward totals are our arithmetic.