What are heat-only boilers? A Complete Guide

Heat-only boilers, also known as conventional or regular boilers, have provided central heating to homes since the 1970s. Despite their long-standing presence in many UK households, many people are unaware of how they work.

Since 2005, condensing boilers have become increasingly popular due to their energy efficiency. However, many homeowners still opt for a heat-only boiler. This article will explore the workings of heat-only boilers, their advantages and disadvantages, and much more. So, let’s dive in!

How do heat-only boilers operate?

Heat-only boilers are responsible for ensuring a continuous supply of hot water and heating for homes. They require a hot water cylinder, cold water storage tank, feed expansion tank, and pump.

The cold-water tank takes the main supply and feeds it into the hot-water cylinder, where a heat exchanger warms the water. This heated water is then supplied to radiators, taps, and showers whenever needed through the pump. On the other hand, a feed expansion tank is essential for maintaining a consistent level of water pressure, as water is often lost from the system through leaks and evaporation.

How do they differ from the system boiler?

Regular and system boilers perform similarly, providing a continuous hot water supply to multiple bathrooms and central heating. However, there are some operational differences between the two and some space requirements. Regular boilers require an expansion tank, a hot water tank, and a cold water storage tank, taking their supply from the loft tank.

They are appropriate for homes with low water pressure flow rates. On the other hand, system boilers take their water supply directly from the mains, eliminating the need for an additional cold water storage tank and saving space. However, because they are highly dependent on main pressure, they are not suitable for homes with low flow rates of water pressure.

How do they differ from combi boilers?

When comparing regular boilers with combi boilers, there is a significant difference between them as they both serve different purposes for different sizes of households. Traditional boilers are ideal for larger homes because they provide continuous hot water and heating, but they require a lot of space.

On the other hand, combi boilers are much more space-efficient and are perfect for smaller homes, as they do not require a hot water and cold water storage tank and take water directly from the main supply.

However, compared to regular boilers, combi boilers cannot provide hot water to multiple bathrooms simultaneously and are also highly dependent on the main’s water pressure, making them unsuitable for homes with low water pressure.

Advantages of a Heat-Only Boiler:

Get uninterrupted hot water at multiple bathrooms simultaneously with different taps and showers.

Open vent boiler simple design makes them relatively easy to maintain; regular annual boiler service will keep them running for 10–15 years. They are ideal for new and old properties with central heating systems.

It is also compatible with solar panels.

If you instal an immersion heater in the hot water cylinder, it will store hot water for future use if your boiler breaks down.

Disadvantages of a Heat-Only Boiler:

Regular boilers are a highly complex system to instal due to the numerous components involved, such as storage tanks and piping. Not only is the installation process costly, but it also requires a significant amount of time to complete.

Space is critical when deciding where to store hot and cold water storage tanks. If you have a smaller household, it may not be feasible to dedicate separate rooms for the water tanks.

You won’t have access to hot water immediately when the stored supply runs out. The tank will take some time to reheat the water, so you should plan accordingly. To ensure you always have hot water on demand, consider investing in a tankless water heater. This system heats water as it passes through the pipes, so you’ll never have to worry about running out of hot water again.

Sometimes, the stored hot water can lose heat if it is not used for a few hours, so you may need to invest in insulating your cylinders, which could incur an additional expense.

What size heat-only boiler do I need?

There are several factors to consider to calculate the size of a boiler before the installation of a new boiler, such as the number of bedrooms, the home’s insulation quality, and the wattage output. For example, if you have a 2 to 3-bedroom apartment with good insulation, the wattage output you would require would be 8 to 9 kW.

On the other hand, if you have a 3- to 4-bedroom home with poor or moderate insulation, the wattage output you would need would range between 14 and 16 kW. Ultimately, it is up to you to make the decision that best suits your needs.

Cost of heat-only boilers from top brands

Brand	Wattage	Warranty Period	Price
Worcester Bosch	9 kw – 42 kw	5 Years	£880- £2300
Potterton	12 kw – 32 kw	7 Years	£730- £870
Baxi	12 kw – 30 kw	3-5 Years	£766- £976
Ideal	12 kw – 36 kw	2-10 Years	£730-£1150
Vaillant	12 kw – 35 kw	2-5 Years	£760-£1597
Glow-worm	12 kw – 30 kw	7 Years	£786-£1600

Conclusion:

To sum up, it’s essential to consider your usage and available space if you’re looking to purchase a heat-only boiler. We’ve provided all the necessary information to help you make the right choice for your needs. If you’d like to learn more about selecting the right boiler, check out our blog for more information on the different types of boilers.

If you’re ready to buy a new boiler or looking for a boiler on finance, you can simply call us at 0345 3192 247 to speak with one of our knowledgeable representatives, who will be happy to answer any questions you may have.