What Is a Heat-Only Boiler?
A heat-only boiler — also widely known as a conventional boiler or regular boiler — is the traditional type of central heating boiler that was standard in UK homes from the 1960s through to the 1990s. Rather than doing everything in a single unit like a combi boiler, a heat-only system uses three separate components: the boiler itself, a hot water cylinder (usually in the airing cupboard), and a cold water storage tank in the loft.
How Does a Heat-Only Boiler Work?
Cold water flows by gravity from the loft tank into the bottom of the hot water cylinder, where it is heated by the boiler via a heat exchanger coil. Hot water rises to the top of the cylinder and is drawn off when taps are opened. A smaller feed-and-expansion tank, also in the loft, keeps the sealed heating circuit topped up. The boiler circulates hot water through the radiator system independently of the domestic hot water supply.
One important consideration is water pressure: because cold water is fed by gravity from a loft tank rather than directly from the mains, the hot water pressure at your taps depends on the height of the tank above the outlet — often resulting in lower pressure than a mains-fed system.
Should You Keep or Replace a Heat-Only System?
If your property already has a well-functioning cylinder and loft tanks, replacing a failed boiler with a new condensing heat-only model is often the most cost-effective solution. However, if you are modernising an older property, many homeowners take the opportunity to switch to a system boiler with an unvented cylinder, gaining mains-pressure hot water and a tidier installation.
Heat-Only Boiler Installation in Corby and Northamptonshire
Our Gas Safe engineers at Corby Boiler Installations are experienced in both replacing heat-only boilers on a like-for-like basis and advising when a full system upgrade makes sense. We work across Corby, Northamptonshire, and the surrounding counties, offering honest, no-pressure advice on the most cost-effective solution for your home.