Boilers 6 min read16 February 2026
There is no universally best boiler type. There is a best boiler for your property, your water pressure and the way your household actually uses hot water.
When a combi is right
Combis suit one-bathroom flats and houses with good mains flow — the sort of properties we work in across Glasgow's West End and newer estates. No cylinder, no loft tanks, hot water on demand, and more usable space.
The limit is simultaneous demand. Two showers running at once on a combi will disappoint everyone.
When a system boiler wins
Larger family homes with two or more bathrooms are usually better served by a system boiler and an unvented cylinder. You get strong simultaneous flow, and the cylinder can be sized to the household.
Measure before you decide
We measure incoming mains flow rate and static pressure at survey. If the flow rate is below about twelve litres per minute, a large combi will underperform no matter what the brochure claims — and a cylinder-based system is the honest recommendation.
Need help with this?
We handle this work every week. See Heating & Boiler Services in Glasgow or browse all our services.
Frequently asked questions
Can I convert from a system boiler to a combi?
Usually yes, provided mains flow rate is adequate. We measure it before quoting.
Do combis work in top-floor tenement flats?
Often yes, but flow rate on upper floors must be checked — we test on site.
Which lasts longer?
Both last well when serviced annually; system boilers have fewer components working on hot water duty.
Related reading
New Boiler Cost in Glasgow: A Straight Answer
Unvented Cylinders: Better Showers, Explained
Central Heating Installation: What to Expect