Boilers

Energy Efficient Heating

No one likes to be cold, so a good boiler can help those cold, harsh nights at bay. From heating your home to providing you with plentiful hot water to wash and bathe in, boilers are an integral part of the modern home.

James Hargreaves supplies a range of domestic and commercial energy-efficient boilers from a variety of market-leading brands such as Ideal and Vaillant.

If you're installing an entirely new system or simply replacing a currently existing boiler, James Hargreaves carries a full range of SEDBUK "A" Rated:

Combination Boilers System Boilers Conventional Boiler

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Combination Boilers

Combination (combi) boilers are the most popular in the UK Market and can be found in around 70% of UK homes. Thanks to their space saving features and energy efficiency, combi boilers are one of the most popular choices in the UK - accounting for over half of domestic boiler installations each year.

Providing central heating and instant hot water without the need for a hot cylinder, combi boilers work by heating mains cold water instantly as it flows through the unit.

Combination Boilers

Sealed System Boilers

The perfect choice for a busy family home with multiple bathrooms. System Boilers use a separate hot water cylinder that contains a large amount of hot water, ready to be piped to multiple locations throughout the home at the same time.

They provide a greater hot water capacity than combi boilers so you can use multiple hot taps at once. Another feature of system boilers is that they provide water at a higher pressure than Combi boilers.

Sealed System Boilers

Ideal Open vent Heating only boiler - Boilers

Conventional Boilers

What sets Conventional or Heat Only boilers apart from a combi or system boiler is it does not operate on a sealed system, the system in this case is subject to external atmospheric pressure, and can be called “Open Vent”.

Open vent heating systems will typically have two cold water storage tanks; a large one for the hot water cylinder which refills the cylinder when the hot taps are used and a smaller tank which connects to the boiler and radiators. This smaller tank allows the water in the radiators to expand.

Conventional Boilers

Which boiler type is best for your home?

The most installed type of boiler in the UK is the combination boiler (small to medium-sized homes), followed by system boilers in larger homes with multiple bathrooms.

Older properties may need to install a conventional boiler to avoid having to replace pipework and radiators. Also homes in areas of low water pressure could find that a conventional boiler delivers better water pressure via its gravity-fed system.

If you are in any doubt about the type of boiler you should install, contact a professional heating engineer in your area who can provide you with advice and a quote for the work.

Should you switch boiler type?

Exchanging an old, inefficient boiler (of any type) for a newer model has many benefits including increased efficiency, lower heating bills and reduced emissions. If you want to keep installation costs to a minimum, a like-for-like boiler replacement may be the cheapest option in terms of upfront costs.

In most cases, homeowners choose to replace a conventional boiler with either a system or a combi boiler unless they are looking for a Low Carbon solution like an Air Source Heat Pump.

Boiler change	Potential benefits	Things to consider
Conventional to System Boiler	You can remove the feed and expansion tanks in the attic. Stronger water pressure (if mains pressure in your area is adequate).	Older pipework and radiators may not be able to cope with stronger water pressure. Mains water pressure may be weak in your area. If so, an additional pump may need to be installed.
Conventional Boiler to Combination Boiler	You can remove the feed and expansion tanks in the attic. You don't need the hot water cylinder in your airing cupboard. Stronger water pressure (if mains pressure in your area is adequate).	A combination boiler may not be able to produce enough hot water for homes with lots of radiators and/or multiple bathrooms without losing pressure and/or temperature. Older pipework and radiators may not be able to cope with stronger water pressure. Mains water pressure may be weak in your area. If so, an additional pump may need to be installed.
System Boiler to Combination Boiler	You can remove the hot water cylinder from your airing cupboard. Hot water would be available on-demand so no more waiting for the cylinder to refill. Reduced heating bills due to not having to heat a hot water cylinder.	A combi boiler may not be able to produce enough hot water for homes with lots of radiators and/or multiple bathrooms without losing pressure and/or temperature.
Combination Boiler to System Boiler	A higher volume of hot water is stored in the cylinder which can supply multiple bathrooms and radiators without losing pressure and/or temperature.	When the hot water in the cylinder has been used up, you will need to wait for it to refill. Heating bills can increase as more energy is required to heat water in the cylinder.

What size of central heating boiler is required?

A key decision relates to the size of the boiler.

The central heating system needs to be powerful enough for the home's needs. The size or output of a boiler is measured in kW. If the boiler is too big for your home, it is likely to waste fuel and make your heating bills unnecessarily high. If a boiler is too small, it will struggle to heat your home.

To work out what size of boiler you need, you should always consult a professional heating engineer. They will consider factors like the number of radiators, the number of inhabitants and the number of bathrooms in your property.

Our table below will provide you with a rough guide as to the size range you should be looking for in your boiler search depending on the size of your home and hot water demand. Since combination boilers need to be able to produce heating and hot water on demand, they are generally more powerful than system or regular boilers.

Number of bathrooms	Number of radiators	Combi boiler recommended size	Number of bathrooms
1	10	24-27 kW	10-18 kW
2	15	27-32 kW	18-26 kW
3+	20	34-42 kW	27-40 kW

Top Brands

Industry-leading brands for Boilers.

James Hargreaves supplies only the highest quality plumbing products from trusted market-leading brands. Our reputation is built on excellent service and top quality plumbing, heating and bathroom products.

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Conventional Boilers

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