Field notes · 6 min read
Choosing a boiler that lasts 20 years
Why the brand on the wall matters less than the engineer behind it — and what to ask before you commission a system.
Boilers are bought twice: once by the homeowner, once by the engineer who installs them. The second purchase matters more.
A boiler is a relatively simple machine. What kills it isn't the brand on the front — it's the system around it. Undersized flues. Tight, badly bent pipework. Poor commissioning. Magnetite circulating through the heat exchanger because nobody fitted a proper filter.
When we specify a boiler we begin with the home: heat-loss calculations, hot-water demand, the condition of the existing pipework, the household's habits. The boiler that comes out of that process is rarely the one in the brochure.
Ask the engineer how they'll commission it. Ask what filter they'll fit. Ask what they'll do to the system before the new appliance ever sees water. The right answers are worth more than a brand name.