Heat Only Boilers — Bournemouth, Poole & Dorset
A heat only boiler — also known as a regular or conventional boiler — is the traditional type found in many older homes across Dorset. It works alongside a hot water cylinder and a cold water feed and expansion tank, and remains the most cost-effective replacement option where that existing setup is already in place.
Installations from £1,299 + VAT · Free Site Visit · Gas Safe Registered · 01202 668822
What Is a Heat Only Boiler?
A heat only boiler heats water that is then stored in a hot water cylinder, and also feeds the central heating circuit. Unlike a system boiler, it requires separate external components — a cold water storage tank and a feed and expansion tank, both typically housed in the loft. The boiler itself is a simpler unit as a result; the additional complexity sits in the wider system around it.
Heat only boilers have been the standard setup in UK homes for decades, and many properties across Bournemouth, Poole, and Dorset still run on them. If your home already has this configuration, a like-for-like replacement is straightforward and avoids the cost and disruption of converting to a different boiler type.
Modern heat only boilers are condensing units, so they’re considerably more efficient than the older open-flued boilers they typically replace — typically achieving ErP A ratings above 90%.
How Does a Heat Only Boiler Work?
A large tank in the loft stores cold water fed in from the mains. This supplies the hot water cylinder below and acts as the primary water source for the system. Because the system is gravity-fed from the loft, water pressure to taps and showers depends on the height difference between the tank and the outlet — known as the head pressure.
The boiler heats a coil inside the hot water cylinder, warming the stored water indirectly. When a hot tap opens, gravity draws water from the cylinder. As the stored volume depletes, the boiler fires again to reheat it. Recovery time depends on the boiler output and cylinder size — typically 30 to 45 minutes for a full reheat.
A smaller tank — also in the loft — keeps the heating circuit topped up with water and provides space for the water to expand as it heats. This open-vented design means the system operates at low pressure, which is simpler but less efficient than a sealed system. Many homeowners fit a shower pump to boost pressure if gravity feed alone isn’t sufficient.
Heat Only Boiler Advantages & Limitations
►Like-for-like replacement is the most cost-effective option if the system is already in place
►Compatible with older pipework — no need to upgrade the wider system
►High hot water volume — multiple outlets can run simultaneously from stored supply
►Simpler boiler unit — easier and cheaper to repair than more complex types
►Requires loft space for cold water and expansion tanks
►Gravity-fed pressure can be low — a pump may be needed for good shower pressure
►Hot water can run out if the stored volume is exceeded — recovery takes time
►Open system is more susceptible to contamination and corrosion than a sealed setup
Is a Heat Only Boiler Right for My Home?
A heat only boiler makes most sense as a like-for-like replacement in a property that already has a cylinder and loft tanks. Converting to a combi or system boiler may offer long-term benefits, but involves additional cost and disruption — particularly in older properties where the pipework is set up for an open-vented system.
During a free site visit, we’ll assess your existing setup and give you an honest comparison of your options. Call us on 01202 668822 to arrange.
Why Choose Dorset Plumbing to Install Your Heat Only Boiler?
Gas Safe Registered ✓ — all engineers hold full Gas Safe registration (No. 943146).
All Major Brands ✓ — we install Worcester Bosch, Vaillant, Baxi, Ideal, Viessmann, Glow-Worm, and more.
Free Site Visit ✓ — we’ll assess your existing system and provide an honest recommendation before you commit.
Transparent Pricing ✓ — fixed written quotes with no hidden charges.
Finance Available ✓ — spread the cost over 2 to 5 years, no deposit on approved credit.
Locally Based in Poole ✓ — fast response across Bournemouth, Poole, and Dorset with no inflated travel charges.
Heat Only Boiler Installation Areas — Bournemouth, Poole & Dorset
We install heat only boilers across Bournemouth, Poole, Christchurch, and the surrounding Dorset area. Because we’re locally based in Poole, response times are fast with no inflated travel charges.
Bournemouth: Boscombe, Southbourne, Winton, Moordown, Charminster, Kinson, Westbourne, Talbot Woods, Pokesdown, Iford, Hengistbury Head
Poole: Sandbanks, Parkstone, Lilliput, Whitecliff, Canford Heath, Broadstone, Hamworthy, Oakdale, Creekmoor, Branksome
Wider Dorset: Christchurch, Highcliffe, Ringwood, Ferndown, Wimborne, Verwood, West Moors, Wareham, Blandford Forum
Not listed? Call us on 01202 668822 — we likely cover your area.
Frequently Asked Questions — Heat Only Boilers
It depends on your property and hot water usage. A like-for-like heat only replacement is cheaper and less disruptive, making it the right choice for many older homes. However, if you want to free up loft space, improve pressure, or simplify the system, converting to a combi or system boiler may be worth the additional investment. We’ll give you an honest assessment during a free site visit.
Yes — a shower pump fitted to a gravity-fed system can significantly boost pressure. Alternatively, an unvented cylinder upgrade converts the hot water side to mains pressure without replacing the boiler. Both are options we can advise on as part of any heat only boiler installation.
Yes — all major manufacturers including Worcester Bosch, Vaillant, and Baxi still produce heat only models. Modern versions are condensing boilers with efficiency ratings above 90%, so a replacement will be significantly more efficient than the older boiler it replaces.
Like-for-like heat only boiler replacements start from £1,299 + VAT. The final price depends on the boiler model and any additional work required. Call us on 01202 668822 to arrange a free site visit and fixed written quote.