Worcester Greenstar 4000 review verdict Yes — the Worcester Greenstar 4000 is the best all-round combi boiler of 2025 for most UK homes. In this detailed Worcester Greenstar 4000 review, we’ve installed over 1,200 units in Watford & Hertfordshire and can confirm: 94% efficiency, super-quiet 45 dB(A), 12-year guarantee, hydrogen-blend ready, and perfect sizing from 25–35 kW. At £1,950... https://warmthheating.com/worcester-greenstar-4000-review-2025/