Solar Panel Installation
in Hemel Hempstead

New Town DNA sets the roof stock apart: Hemel was designated a New Town on 4 February 1947 to Geoffrey Jellicoe's masterplan, with Adeyfield the first neighbourhood built (first houses at Longlands went up in spring 1949; the first families moved in on 8 February 1950). Housing from that period across Adeyfield, Bennetts End and later Grovehill/Woodhall Farm varies, so we survey the roof structure and covering before designing any system.

Homes bordering the Box Moor Trust estate have a genuinely local quirk worth planning around: the Trust, founded in 1594 and governed by trustees elected from residents on the Hemel Hempstead and Bovingdon electoral roll, manages nearly 500 acres of open-access common land (watermeadows, chalk downland and recreational moor at Blackbirds Moor and Chaulden). Properties fronting this open land at Boxmoor, Chaulden and Corner Hall enjoy an unusually open, un-shaded aspect that helps year-round yield, though south-facing elevations facing the common are more visible and benefit from a low-profile, in-roof or flush-mounted layout.

East and north Hemel is the growth frontier: Hemel Garden Communities (a Dacorum, St Albans and Hertfordshire County Council partnership) is planning around 11,000 new homes and 10,000 jobs by 2050, including the Hertfordshire Innovation Quarter next to Maylands Business Park, with outline applications from late 2025 and construction from 2027. New-build and self-build owners near Leverstock Green and east Hemel should specify solar, battery and EV-charger provision at design stage, when integrated in-roof mounting and cabling are far cheaper than retrofitting.

UK Power Networks, which distributes electricity across the East of England, runs the local network your Hemel Hempstead system will connect to. In August 2020 it was replacing one transformer at its Warners End substation in Hemel Hempstead with two new 33/11 kV transformers, to boost reliability for more than 8,000 customers. For solar, the network operator's rules matter as much as the council's. Under the ENA's G98 standard, generation up to and including 16 A per phase (3.68 kW on a single-phase supply) is notified by the installer no later than 28 days after commissioning, and batteries count towards that total. MCS says that when battery storage is added to solar PV, total connected generation is likely to be above 16 A per phase, so G99 applies instead and UK Power Networks is consulted before installation. A Tesla Powerwall 3 on its own is rated at 11.5 kW continuous, well above 3.68 kW, so it is worth building that step into your timeline.

Census 2021 counted 63,413 households in Dacorum, the borough that includes Hemel Hempstead. Terraced homes were the largest group at 29.8% of households, followed by semi-detached (25.0%), detached (21.3%) and purpose-built flats (20.6%). On tenure, 63.9% of households owned their home, 21.0% rented socially, including 15.6% renting from the council or local authority, and 14.3% rented privately. These are borough-wide figures rather than Hemel Hempstead alone, but with more than a third of households renting and around a fifth living in purpose-built flats, it is worth confirming early who is responsible for the roof and whose agreement is needed before anyone designs a system.

The European Commission's PVGIS model gives a useful starting point for a Hemel Hempstead roof. Run for the town's coordinates with PVGIS-SARAH3 solar data, 14% system losses and a 35-degree pitch, one kilowatt-peak of panels facing due south is modelled at about 1,021 kWh a year. Facing south-east it is about 966 kWh, south-west about 955, east about 814 and west about 798. The seasonal swing is large: about 125 kWh per kilowatt-peak in July against about 34 kWh in December. As a worked example, ten AIKO 485W panels (4.85 kWp) on a south-facing roof would be modelled at roughly 4,950 kWh a year, but only around 5.3 kWh a day in December, before any shading from nearby trees or buildings. So an east or west roof is still worth surveying, and solar will charge a battery far more in summer than in winter.