A 3-bedroom semi-detached house is the UK's most common property type — and it has specific heating requirements that make the boiler choice fairly clear. Here are our engineers' top recommendations.
What size boiler?
A standard 3-bed semi with one bathroom needs a combi boiler in the 28–32 kW range for central heating. The DHW (domestic hot water) output should be at least 35 kW to give a decent shower flow rate.
Combi or system?
For a 3-bed semi with one bathroom and up to 4 occupants, a combi boiler is almost always the right choice. It's simpler, cheaper to install, and eliminates the cylinder — freeing up the airing cupboard.
If you have two bathrooms and regularly run two showers simultaneously, step up to a system boiler with a 250-litre unvented cylinder.
Our top recommendations
Best value: Ideal Logic Max 30 — £999 fitted. 93.6% efficiency, 10-year warranty, proven reliability. Ideal for straightforward replacements where budget is a consideration.
Best mid-range: Worcester Bosch Greenstar 4000 28 kW — £1,199 fitted. Outstanding reliability, 10-year warranty (12 years with us), excellent controls.
Premium: Vaillant ecoTEC Plus 30 kW — £1,399 fitted. 94% efficiency, exceptional build quality, up to 10-year warranty.
One extra investment worth making
Whichever boiler you choose, add a magnetic filter (£149 fitted with the boiler). It protects the heat exchanger from sludge and is required by most manufacturers to keep the warranty valid. The investment easily pays for itself in prevented repairs.