Combi Boilers

Combination boilers (combi boilers) provide both heating and hot water but do not use a hot water storage tank. They are perfect for 1-2-bedroom flats, 3–4-bedroom homes and spaces without a lot of room for a larger system but also need a good flow rate of cold water to operate properly since they have no storage tank.

Combi boilers are a substantial option for smaller spaces. A good combi boiler can provide the same benefits as a system boiler with far less space needed, and most combi boilers are also very efficient. A combi boiler will be weaker but also consume less power. They can instantly heat the water you need you will not have to wait around for that hot, sultry shower.

Typically, not suitable for larger properties with multiple bathrooms/or a high hot water demand.  

May not be suitable for areas that suffer from low mains water pressure.

System Boilers

System boilers are part of your central heating system and the water storage system, they take water directly from the mains instead of a feed tank in loft. They are very resourceful as they are able to heat up several rooms and operate multiple bathrooms without dropping the temperature of heating systems.

A system boiler can be a good option among all regular boilers, acting like a larger combi boiler. If you want to stick to regular boilers and avoid complex features that you will not ever use, a system boiler can be a great choice.

The downside is their size - they need a large hot water storage tank. If this tank is drained due to high water usage over a long period of time, it can take a little while for the system boiler to refill it. The high-pressure nature of this system means that it may not be suitable for properties with older systems. 

System boilers need a hot water storage cylinder and so if you are swapping it for a combi boiler, you will need to find adequate storage space. 

Heat Only (Regular Boilers)

A heat-only or regular boiler has three main components – the boiler itself, a separate hot water storage cylinder and cold-water storage tank.

The boiler supplies hot water to both the central heating and storage cylinder, so can provide both hot water and heating water. As they do not require water to be supplied at high pressure via the mains, they are a good option for older heating systems that may not tolerate the high pressure of a closed system. 

Coldwater is supplied to the boiler via a cold-water tank (typically located in the attic/loft), which fills the boiler with the help of gravity.  Since they require a cistern tank, they demand more space and limit boiler installation options. A cistern in the attic is prone to freezing during winter and if it leaks can be problematic.

You can take a look at our average boiler prices here, but you will need to have a survey first before installation. This is best practice for any central heating installation as your property is unique – and so is the placement of your boiler. We wouldn’t want to quote over the phone for an unseen property as this is misleading.

You may find upon survey that some additional work is required – such as movement of a flue in order to comply with the latest building regulations or running of condensing pipe as some old boilers are non-condensing. While this may feel like an inconvenience, this work would be required by any boiler replacement engineer to remain compliant, safe and validate manufactures guarantee/ warranty.

Our engineer will arrive with your boiler and all the necessary parts. They usually arrive between 8-11am.
Our Gas Safe engineers will carry out the work to the highest possible level, making sure they protect any areas in which they work and cleaning up any areas in which they have worked.

A like-for-like boiler replacement would on most occasions take 1-2 days. However, if you are moving home, or you require an upgrade, or you need new radiators, the installation may take longer. If we converting from conventional system to combi, it may take 2-3 days. For full new system it may take 3-4 days.