What Is a Heat Only Boiler? Your Complete Guide

If you're exploring your home heating options, you’ve probably come across the term heat only boiler. Also known as a regular or conventional boiler, this system is a classic choice that’s still going strong in UK homes—especially in larger or older properties. But what exactly is a heat-only boiler, how does it work, and is it the right fit for your household?

Let’s break it down in simple terms.

How Does a Heat Only Boiler Work?

A heat only boiler works in tandem with two key components: a hot water cylinder and a cold water tank (typically stored in the loft). Unlike combi boilers that provide hot water on demand, a heat-only boiler heats and stores hot water for later use.

Here’s what happens: cold water from the storage tank is fed into the boiler, where it’s heated. This hot water is then sent to the cylinder for storage. When you turn on a tap or switch on the heating, hot water flows either through your pipes to your radiators or to your taps and showerheads. It’s a tried-and-tested system that’s built for reliability.

What is a heat only gas boiler?

The main appeal of a heat-only boiler lies in its steady performance and ability to supply large amounts of hot water. For families or homes with multiple bathrooms, that’s a major plus. With a dedicated cylinder, several people can use hot water at the same time without affecting pressure or temperature.

These boilers also work well with older central heating systems, making them a go-to option when upgrading an older property where pipes and radiators may not be suited to the high pressure of combi systems.

Pros of boiler 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 Keep in Mind

Of course, no heating system is perfect. Heat-only boilers do need more space due to the extra components: the hot water cylinder and the loft storage tank. This setup also means installation is more complex compared to simpler systems like combi boilers.

There’s also the matter of heat loss. Since hot water is stored rather than heated on demand, some energy can be lost over time unless your tank is well insulated.

Is It the Right Boiler for Your Home?

You might want to seriously consider a heat-only boiler if you live in a home with multiple bathrooms or you have a traditional heating setup with older pipework. It’s also a solid choice in areas where mains water pressure is low.

On the other hand, if you’re in a small home or apartment with limited storage space—or you want instant hot water without waiting for a cylinder to fill—a combi boiler could be a better fit.

What Does It Cost?

The cost of installing a heat-only boiler depends on a few factors, including the brand, boiler size, and the complexity of your home’s heating setup. Generally, you can expect the boiler by itself excluding a flue to cost anywhere between £900 and £2,500. Installation adds another £500 to £1,500, depending on what’s already in place.

It’s an investment—but for the right home, it pays off in comfort, reliability, and long-term value.

Need Expert Advice? We’re Here to Help

If you're not sure whether a heat-only boiler is the right choice for your home, Thermo-Tec Plumbing and Heating is just a call away. Our experienced team offers professional guidance and expert installation services across Reading, Earley, Wokingham, Woodley, Barkham and surrounding areas.

Call us today on 07850 116944
Or book online at www.thermo-tec.co.uk

We’re a local, family-run business—and we’re ready to help you find the perfect heating system for your home.