Conventional boiler replacement

What a conventional boiler is

A conventional boiler — also called a regular or heat-only boiler — heats water for the radiators and for a hot water cylinder, with a cold water tank in the loft feeding the system by gravity. It is the setup found in many older houses, and there is nothing wrong with it: for homes with several bathrooms or a weak mains supply, it remains a sensible design.

Replacing one like for like is usually the simplest boiler job there is, because the pipework, cylinder and controls are already arranged around it.

When keeping the conventional setup makes sense

• Two or more bathrooms are used at the same time — stored hot water copes better than a combi
• Your mains water pressure or flow is poor — a gravity-fed system does not rely on it
• The existing pipework and radiators were designed around the current system
• You want the least disruption: no tanks removed, no pipework reworked

System vs regular boiler

A system boiler is the middle ground: it still works with a hot water cylinder, but takes its water from the mains, so the loft tank goes. That removes the frost risk and the weight of a tank full of water above your bedroom, while keeping the stored hot water that busy bathrooms need.

If your loft tank is old, or you would simply rather it was gone, a system boiler installation is worth considering at replacement time. Our combi vs system boiler guide compares the wider options.

What the replacement involves

The old boiler is drained down, disconnected and removed, and the new one is fitted on the existing pipework. The flue and condensate arrangements are brought up to current standards, the system is cleaned if needed, and the controls are checked or upgraded. Because the cylinder and tank stay, the disturbance is much less than a conversion.

It is still worth having the cylinder looked at while the boiler is changed — an old cylinder with a new boiler can be the weak link. Our hot water cylinder installation page explains the signs of a cylinder near the end of its life.

Considering a combi instead?

Some households use a boiler replacement as the moment to change system type. If you want the cylinder and loft tank gone and your mains supply is up to it, read about combi conversion. Chris will give you an honest view of which route suits your home at the survey — there is no one right answer.

Get a quote

Send photos of the boiler, cylinder and loft tank via WhatsApp or use the new boiler quote page. The survey and written quote are free, and you will know exactly what is included before any work is booked.