What Is a Heat-Only Boiler? A Simple Guide for UK Homeowners

If you're looking into new heating options for your home, you’ve probably come across something called a heat-only boiler. Also known as a regular or conventional boiler, it’s a traditional system that's still widely used in the UK—especially in larger homes or older properties with existing pipework.

But what exactly is a heat-only boiler, how does it work, and is it the right choice for your home? Let’s break it down in plain English.

How Does a Heat-Only Boiler Work?

A heat-only boiler works alongside two other components:

A hot water storage cylinder (usually found in the airing cupboard)
A cold water tank (often located in the loft)

Here’s how the system works:
Cold water flows from the tank into the boiler, where it’s heated. The hot water is then stored in the cylinder until you need it—for example, when you turn on the taps, run a bath, or switch on your heating.

Unlike combi boilers, which heat water instantly, heat-only systems store hot water in advance, so it's ready when you need it. That makes them ideal for busy households with multiple bathrooms.

Pros of heat only systems

If you have a bigger home or a busy household, a heat-only boiler could be just what you need. It’s great for meeting higher hot water demands, especially when showers and taps are in regular use across multiple rooms.

Another advantage is its compatibility with low-pressure areas. If your home suffers from weak mains water pressure, a heat-only boiler connected to a gravity-fed system can keep everything flowing smoothly. Plus, these systems can be paired with solar thermal panels, helping you cut down on energy bills and boost your home’s eco-credentials.

And here’s a bonus—if the boiler itself has an issue, you’ll still have access to stored hot water from the cylinder, giving you some breathing room while repairs are arranged.

Things to Consider

Like any system, heat-only boilers have their pros and cons. It’s worth keeping these points in mind:

They take up more space. You’ll need room for both a hot water cylinder and a cold water tank—so they’re not ideal for smaller homes or flats.
Installation is more involved. Because of the extra components, installing a heat-only boiler tends to take a bit more time and planning.
Stored water can lose heat. Unless your hot water cylinder is well-insulated, some heat will gradually escape over time.

Is a Heat-Only Boiler Right for Your Home?

You might want to consider a heat-only boiler if:

You have multiple bathrooms in regular use
Your home has older heating infrastructure that may not handle a high-pressure system
You live in an area with low water pressure
You're planning to use solar thermal panels in the future

On the other hand, if you’re short on space or want instant hot water without relying on storage tanks, a combi boiler might be a better fit.

How Much Does Installation Cost?

Installing a heat-only boiler typically costs between £1,400 and £4,000, depending on the complexity of your existing setup and which system you choose. This includes supply and installation by a qualified heating engineer.

At Thermo-Tec, we offer free, no-obligation quotes and honest advice—so you’ll know exactly what you’re paying for, with no hidden extras.

Local Experts in Heat-Only Boilers – Here to Help

Still not sure if a heat-only boiler is the right option for your home? That’s what we’re here for. At Thermo-Tec Plumbing and Heating, we’ve helped hundreds of homeowners across Reading, Wokingham, Earley, Woodley, and Shinfield find the perfect heating system for their needs.

Our team is fully Gas Safe registered, and we’re proud to be a local, family-run business with years of experience.