The Boiler Guide

The Only Boiler Guide You Need


Guscott Heating Services

boiler guide

The Boiler Guide

Buying a new boiler. Not the sexiest of purchases you’ll ever make, but an important one to see you and your family through the Great British winter. There are many different options available, from combis to conventionals, electric to gas, and more. Your choice depends on a myriad of factors such as your budget, the size of your home, how many people live in the house and even where the boiler will be located.

Hopefully, our advice below can help you make an informed decision and have confidence that you’ve picked the perfect system for your home.

The types of boiler available

There are three main types of gas boiler to consider:

  • Combi (combination)
  • Conventional
  • System

Combi boilers

Combi boilers are the most popular type of boiler in the UK and they make up over half of all new boilers being fitted. A combi is effectively an all-in-one boiler solution that operates as a highly efficient heating and hot water boiler. They don’t need a separate hot water cylinder, which means they’re great for smaller homes or homes with space-conscious considerations.

A combi boiler heats water directly from the mains instead of drawing water in a tank that’s usually located in your loft (as such a conventional boiler). This means you can get hot water on demand without the risk of ever running out. Without a cold water tank, the costs of installation are reduced, as well as the cost of materials required.

Their small size means that they’re perfect for installing within a kitchen cupboard. They run quietly but are still powerful enough to deliver all of your heating and hot water needs making them a great choice.

A consideration with a combi boiler is the mains pressure in your area. Because a combi will deliver water at mains pressure, without the need for a separate pump or power shower, you may find the water exiting the taps or showers is quite weak if your area struggles. This will be exacerbated further if multiple taps or appliances are on around the house. If you are worried about the pressure of your water, speak to your water supplier or speak to OFWAT who independently regulate the industry.

Conventional boilers

Typically found in older properties, they are the perfect boiler for homes where there is a high demand for hot water or in buildings where there is a large number of bathrooms. 

These types of systems do require space for a hot water cylinder, where the heated water is kept until it is needed, and a cold water tank, where freshwater is pulled in and stored, ready to be heated. In some cases, an immersion heater can be added too, so if your boiler breaks down for any reason, you have a backup hot water supply.

While offering an effective solution, the hot water cylinder and cold water tank could be a problem for small homes, and this is why combi boilers have significantly increased in popularity. Once the hot water in the cylinder has run out, you would need to wait for the boiler to heat more water, meaning you may need to exit a cold shower and wait for 30 minutes for more hot water, for example. Generally, this won’t be an issue, as you can programme the thermostat to preheat the water at set times. If your household tends to have showers in the morning, you could set the boiler to begin heating water at 6 am, for example, ready for everyone’s 7 am shower.

boiler guide

System boilers

A system boiler works on the same principles as a combi boiler, heating water directly from the mains. However, a system boiler also has a domestic hot water storage cylinder.

This means that a system boiler is an ideal choice for households that consume a lot of hot water, allowing multiple hot water taps to be used at the same time with little to no impact on water pressure.

It’s very important to get the sizing correct for a system boiler, or you may find that the tank isn’t big enough to store all the hot water you need.

Know your heating and hot water demands

 Now that you understand the three main types of boiler available, you should work out how much hot water you use to understand the system right for your home.

Small terraced house, flat or bungalow

For these smaller builds with one to two bedrooms and up to 10 radiators, a 26-30kW boiler will be more than enough.

Medium terraced house, semi-detached house or bungalow

For a medium-sized build with up to four bedrooms and 15 radiators, a slightly bigger boiler is recommended, closer to 30kW+. A DHW storage boiler could be the most advantageous as it won’t take up too much space but will still meet your hot water needs.

Large semi-detached or detached house

For a large house with four or more bedrooms and up to 20 radiators, a 30-35kW  system boiler is recommended. This will be able to store hot water for when you need it with no reduction in water pressure when using multiple appliances.

Assess your budget

There isn’t a ‘one price sets all’ mechanism when it comes to boilers and before you can make any decisions about which make, model or type you’ll go for, you need to know your budget. 

Boiler prices generally depend on the brand, the type of boiler (combi, conventional or system) and the size of the boiler. Generally, a combi boiler will be the most reasonable, and system or conventional choices could be pricier. You should also take into consideration that the installation cost will not be included in the price of the boiler.

Location, location, location

Picking a location for your boiler is important as this could impact the type of boiler you choose. If you’re replacing like for like, then this won’t be an issue. If you wish your boiler to be hidden in a kitchen cabinet, then you’ll likely need a combi boiler that’s small enough for this. It is worth considering the location of the boiler to allow the shortest possible flue run to avoid excess costs when installing large flue systems for the removal of waste gases.

Any flue fitting must conform to manufacturing installation instructions and gas safety regulations – your installer will be able to help give clarity on this.

Secure your warranty

The length of the warranty may impact your decision when buying a new boiler. Boilers can be a significant investment, and you want to make sure that it’s covered should anything go wrong within the first few years of ownership. Most boilers come with a warranty, but the length of these can vary from two to 12 years. The longer the warranty, the better but these do typically come at a higher cost. Understand how much you value long-term peace of mind and use this to help make your decision.

Given boilers come in all different shapes and sizes, the important thing to do is pick the system that best suits your needs based on a thorough evaluation.

Guscott Heating Services help all of our customers get access to our expert team of Gas Safe engineers who can help advise you on which boiler type is most suitable for your property. The team have a wealth of knowledge and experience that can help prevent you from making the wrong purchase and rest assured your home will be warm and toasty for years to come.

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