Forty-nine firms — 28 limited companies, 12 sole traders — with plumbing (28) and central heating (24) as the core, and specialist tails in underfloor heating (13), bathroom installation (10), and renewables (9 firms fitting air-source heat pumps). Guernsey Gas dates to 1823; the newest opened 2025. Nine firms belong to the GBTEA. —
Thirty-six plumbers — 20 limited companies, 10 sole traders — weighted toward St Sampson (8), with a renewables cohort of nine.
Forty-two heating engineers on the island — 14 in underfloor heating, 12 boiler installation, 11 air-source heat pumps.
Seven gas engineers — six limited companies and one sole trader — anchored by Guernsey Gas, the island's utility with heritage to the 1820s.
One firm per niche, picked for editorial depth.
Plumbing and heating specialists — boilers, renewables, 24/7 emergency service.
Fuel & gas supplier; only supplier of Maxiheat premium heating oil, with OFTEC approved technicians
Island gas utility — natural gas, bottled gas, and low-carbon alternatives.
Municipal services: engineering, waste, land, emergency response