| Horizon Technical Ltd | Banbury | 2018 |
| Horna Bess Limited | Bristol | 2022 |
| Hornage Green Energy Limited | London | 2022 |
| Horndon Electrical Testing Limited | West Horndon | 2026 |
| Hornsey Heating Ltd | London | 2025 |
| Hornsey Hill Wind Farm Limited | Shipley | 2026 |
| Horsacott Solar Limited | Reading | 2012 |
| Horse Close Green Power Limited | London | 2022 |
| Horsepark Wind Ltd | Belfast | 2015 |
| Horseway Energy Ltd | Chatteris | 2014 |
| Horsey Levels Renewable Energy Limited | Cheltenham | 2021 |
| Horsfields Solar Limited | Wakefield | 2023 |
| Hortus Green Limited | Boston | 2018 |
| Horus Partners UK Limited | Reading | 2021 |
| Horwich Aerials Installations Limited | Bolton | 2009 |
| Hospital Shields Energy Ltd | Forfar | 2014 |
| Hosswind Ltd | Newbiggin By The Sea | 2023 |
| Hot Rads Homes Ltd | Stoke-On-Trent | 2025 |
| Hotham Energy Limited | Beverley | 2011 |
| Hough Portable Events Limited | Stafford | 2005 |
| Houghton Energy Ltd | Kings Lynn | 2012 |
| Houlkair Ltd | Lymm | 2020 |
| House Nine Limited | Manchester | 2009 |
| House O' Hill Wind Energy Limited | Roslin | 2009 |
| Househill Bess Limited | Mirfield | 2022 |
| Houseline Solar Ltd | Birmingham | 2025 |
| Housemate Bills Limited | Leicester | 2024 |
| HOW Connection Four Limited | London | 2021 |
| HOW Connection One Limited | London | 2021 |
| HOW Connection Three Limited | London | 2021 |
| HOW Connection Two Limited | London | 2021 |
| Howard Tenens Power (HTP) Limited | Stroud | 2022 |
| Howard Tenens Power (Project a) Limited | Thrupp, Stroud | 2023 |
| Howat’S Hill Energy Park Limited | Glasgow | 2025 |
| Howbery Solar Park Limited | Bristol | 2011 |
| Howden Renewables Limited | East Lothian | 2012 |
| Howell Electrical Services Limited | Cambridge | 2019 |
| Howlett House Wind Farm Limited | Houghton-Le-Spring | 2026 |
| Howmuir Solar Limited | Edinburgh | 2015 |
| Howsham Power Co Ltd | York | 2009 |
| HOY Energy Limited | Stromness | 2009 |
| HP Solar Limited | Royston | 2013 |
| HQ Energy Centre Ltd | Liverpool | 2022 |
| HQ Security & Electrical Ltd | London | 2024 |
| HRE W Solar Limited | Stroud | 2016 |
| HRE Willow Limited | Stroud | 2011 |
| HRH Utilities Ltd | Greenhithe | 2025 |
| Hrossey Investments Limited | Ilkley | 2013 |
| HS Energy Limited | Londonderry | 2014 |
| HS Energy Service Ltd | Barking | 2018 |
| HS Group (Yorkshire) Limited | Barnsley | 2026 |
| HS Residential 1 Limited | London | 2023 |
| HS Utilities Ltd | Stoke-On-Trent | 2023 |
| Hs.Connect Ltd | Colchester | 2026 |
| HSS Inspection Services Limited | | 2008 |
| HTW Turbines Ltd | Belfast | 2014 |
| Huangoumituo Limited | Cardiff | 2026 |
| Hubber NO 4 Limited | Grimsby | 2025 |
| Huddle Utilities Ltd | London | 2015 |
| Huddlestone Renewables Limited | Goole | 2013 |
| Hudlow Ltd | London | 2024 |
| Hudson Electrical Solution Limited | Birmingham | 2021 |
| HUE Solarity Limited | London | 2025 |
| Hugo Energy Limited | Norwich | 2019 |
| Hull Energy Ltd | London | 2023 |
| Hull Renewables Ltd | Evie | 2012 |
| Hull Reserve Power Limited | Bristol | 2011 |
| Hulse Energy Limited | London | 2014 |
| Hulse Renewable Energy Limited | London | 2015 |
| Hulver Road Solar Limited | Liverpool | 2023 |
| Huma Electrical Limited | London | 2014 |
| Humber East Holdings Ltd | Hull | 2023 |
| Humber Gateway Ofto Holdings Limited | London | 2016 |
| Humber Gateway Ofto Intermediate Limited | London | 2016 |
| Humber Gateway Ofto Limited | London | 2016 |
| Humbly Grove Energy Services Limited | Alton | 2004 |
| Humidity Solutions Limited | Leatherhead | 2008 |
| Humidity Specialists Ltd | Maidstone | 2024 |
| Humpty Dumpty Limited | Newcastle Upon Tyne | 2019 |
| Hunciecroft Solar Limited | Hove | 2014 |
| Hunger Hill Solar Project Limited | Hove | 2014 |
| Hungerford Solar Projects Limited | Reading | 2015 |
| Hunmanby Solar Limited | London | 2025 |
| Hunt Air Conditioning Ltd | Wallsend | 2022 |
| Hunter's Hill Wind Farm Limited | Londonderrry | 2007 |
| Hunters Race Solar Limited | London | 2012 |
| Hunterston Data Centre Limited | Edinburgh | 2025 |
| Hunterston EV Ltd | Motherwell | 2025 |
| Hunterston Grid 1 Ltd | London. | 2017 |
| Hunterston Grid 2 Ltd | London | 2021 |
| Hunterston Grid 3 Ltd | London | 2017 |
| Hunterston PV Ltd | Motherwell | 2025 |
| Huoli Dragonfly Capital Limited | Leeds | 2017 |
| Hurcott Solar Limited | Hove | 2014 |
| Huron Solar Limited | London | 2023 |
| Hursit SPV 1 Limited | London | 2012 |
| Huskisson Welding Company Limited | Liverpool | 1983 |
| Husky Electricals Ltd | Dorchester | 2023 |
| Hutchinson Refrigeration Services Ltd | Ilkeston | 2016 |
| Huthwaite Solar Farm Limited | Birmingham | 2015 |