| HDB Surveys & Engineering Limited | West Midlands | 2003 |
| Headcorn Solar Limited | West Byfleet | 2013 |
| Headley Green Limited | Selby | 2011 |
| Headwind Development Services Limited | London | 2009 |
| Healey Electrical Services Ltd | London | 2019 |
| Healthcair Commissioning and Validation Services Ltd | Sidmouth | 2023 |
| Healthiest Homes Limited | Faversham | 2019 |
| Healy's ACR Limited | Tadworth | 2014 |
| Heanor Energy Storage Park Limited | London | 2023 |
| Heap Bridge Hydro Ltd | St Albans | 2017 |
| Heat Centre (Wick) Limited | Wick | 2009 |
| Heat Collector Ltd | Bracknell | 2011 |
| Heat Economy Limited | Bromsgrove | 2014 |
| Heat Haven Limited | Gloucester | 2021 |
| Heat House Farm Ltd | St, John'S Wood | 2024 |
| Heat Networks Development Company NO.1 Limited | Blackburn | 2026 |
| Heat Pump & Cooling Aftercare Ltd | Manchester | 2026 |
| Heat Pump Installs Ltd | Buckingham | 2019 |
| Heat Pump Solutions Limited | Hastings | 2020 |
| Heat Recovery (Hvac) Limited | Milton Keynes | 2020 |
| Heat Safe GAS Services Ltd | Newcastle | 2014 |
| Heatalia Utilities Ltd | Bishopton | 2022 |
| Heatek Limited | Bromsgrove | 1997 |
| Heatfields Heating and GAS Limited | Nottingham | 2026 |
| Heatguard Services Ltd | London | 2025 |
| Heath Farm Energy Limited | Guildford | 2015 |
| Heath Road Energy Centre Limited | Norwich | 2021 |
| Heather Moor Wind Farm Limited | London | 2026 |
| Heathland WF Limited | Glasgow | 2011 |
| Heathland Windfarm Limited | Houghton Le Spring | 2010 |
| Heathlands Solar Ltd | Carlisle | 2020 |
| Heathtech Ltd | Knighton | 2015 |
| Heating 4 U Ltd | London | 2026 |
| Heating Homes & Plumbing Ltd | Shropshire | 2024 |
| Heatthrow Ltd | London | 2025 |
| Heatwave Plumbing & Heating Ltd | Cheltenham | 2019 |
| Hebe Traders Ltd | Great Bookham | 2004 |
| Hebridean Energy Limited | Isle Of South Uist | 2002 |
| Hebrides Energy Community Interest Company | Stornoway | 2015 |
| Heck FEN Wind Park Limited | Stroud | 2012 |
| Hedgehog Grove Solar Farm Limited | London | 2021 |
| HEG Holdings Limited | Ayr | 2018 |
| HEI Group (SW) Limited | Newton Abbot | 2018 |
| Heidi Air Conditioning Limited | Andoversford | 2016 |
| Heidro Harnog CYF | Gwynedd | 2003 |
| Heightec Solutions Ltd | Dundee | 2024 |
| Hele Manor Limited | London | 2016 |
| Heliofidem UK Ltd | Manchester | 2021 |
| Heliogate Ltd | Crawley | 2025 |
| Helios Capital Prime Ltd | London | 2025 |
| Helios Energy Ltd | Glasgow | 2025 |
| Helios Mechanical Solutions Ltd | Haslemere | 2016 |
| Helios Solar 1 Limited | London | 2015 |
| Helios Solar 2 Limited | London | 2015 |
| Helios Volt Limited | Newcastle Upon Tyne | 2023 |
| Heliosx Energy Limited | Leamington Spa | 2023 |
| HELIUM-3 Technologies Limited | Saffron Walden | 2021 |
| Hello Soft Ltd | Southampton | 2020 |
| Hellums Field Solar Park Limited | Exeter | 2012 |
| Helm Power 2 Limited | London | 2019 |
| Helm Power Limited | London | 2019 |
| Helmdon Blackpits Power Limited | Wellingborough | 2014 |
| Help for Heating Limited | Bristol | 2018 |
| Heman Limited | Ashbourne | 2015 |
| Hemera Energy Limited | Uckfield | 2016 |
| Hemswell Biogas Limited | Gainsborough | 2014 |
| Hemswell Clean Tech Green Power Ltd | Gainsborough | 2020 |
| Hemswell Power Solutions Limited | Gainsborough | 2020 |
| Hendai Solar Limited | Hove | 2013 |
| Henderston Renewables Limited | Forfar | 2015 |
| Hendir Uchaf Solar Ltd | Bridgend | 2024 |
| Hendre Fawr Solar Limited | Hove | 2013 |
| Hendre Wind Limited | Abergele | 2016 |
| Hendrie & Kerr Limited | Maybole | 2013 |
| Hendrie Biotech Limited | Kilmarnock | 2009 |
| Hengrove Solar Limited | London | 2021 |
| Henley Solar Farm Ltd | London | 2014 |
| Henoc Ltd | Halesowen | 2018 |
| Henry Energy Limited | Huntingdon | 2021 |
| Henshaw & Henshaw Ltd | Durham | 2008 |
| Heolddu Solar Park Limited | London | 2024 |
| Hepworth Place Esco Limited | Blackburn | 2017 |
| Hereford Solar Limited | London | 2015 |
| Herefordshire Biogas Ltd | Leominster | 2013 |
| Hereward GAS Limited | Peterborough | 2003 |
| Hermia Community Energy C.I.C. | London | 2015 |
| Hermitage Solar Farm Limited | London | 2013 |
| Hermitage Solar Limited | Reading | 2014 |
| Hermitage Solar Park Limited | Reading | 2013 |
| Hero Surveyor's Ltd | London | 2022 |
| Heron Energy Limited | Magherafelt | 2023 |
| Heron Oughtboy Limited | Magherafelt | 2024 |
| Heron Power Limited | Magherafelt | 2018 |
| Heron Storage Development Limited | Magherafelt | 2026 |
| Heron Storage Limited | Draperstown | 2021 |
| Heron Storage NO. 2 Limited | Magherafelt | 2024 |
| Heron Storage NO. 3 Limited | Magherafelt | 2025 |
| Heron Storage NO. 4 Limited | Magherafelt | 2025 |
| Heron Storage NO. 5 Limited | Magherafelt | 2026 |
| Heron Storage NO. 6 Limited | Magherafelt | 2026 |