Heating your home and producing hot water should not have to be complicated. It is not, after you choose the right kind of boiler, but boiler shopping itself can be a bit challenging. With literally hundreds of choices to consider, you can drive yourself crazy trying to understand all the fine details of every brand and model.
So you’re in the market for a new combination boiler. How do you choose the best one in 2019? As is the case with almost every home renovation project, it is all about knowledge. Educating yourself as to the different kinds of boilers and what they do makes it a lot easier when you’re actually pricing them out. You will know what you’re looking at and what you are paying for.
We will get to some estimated prices later on in this guide. First though, let us talk about what a combi boiler is as compared to other types of boilers.
Three Kinds of Boilers
The combi boiler is not the only type of boiler you can buy. In fact, it is the most modern of the three primary boiler types here in the UK. Let’s look at all three to see what they do:
1. Open Vent Boiler
Open vent boilers are also known as conventional or standard boilers for the simple fact that they are the most commonly used in the UK. This sort of boiler is installed on an open vent central heating system. Making it all work requires a feed tank, an expansion tank, and the hot water cylinder.
The feed tank stores water that circulates throughout the house for heating purposes. The expansion tank holds cold water, while the hot water cylinder is used to produce the hot water that comes out of your taps.
2. System Boiler
A system boiler is similar to an open vent boiler with one notable difference: it does not utilise the expansion tank for cold water. Rather, cold water flows directly from the mains to taps, toilets, etc. This set-up is advantageous in homes where there is little space to install cold water expansion tanks.
3. Combi Boiler
The combi boiler is completely different from the other two styles. It is an on-demand boiler that has neither expansion nor hot water tanks. Instead, it heats water on-the-fly. It has two different heat exchangers for two different kinds of water.
The main heat exchanger is responsible for heating the water being used to provide heat. The system through which this water flows is a sealed system containing water that would be unsuitable to drink.
A secondary heat exchanger heats the water that comes out of the home’s taps. When hot tap water is required, a valve opens and diverts water from the heating system into a secondary closed system that heats the tap water. As for cold water, it comes in directly through the mains.
Choosing the Right Style of Boiler
Before you begin shopping for a boiler it is important to consider what kind of set-up is right for your situation. Vent and system boilers are generally recommended for larger homes. Detached, semi-detached, and end-terraced homes with three or more bedrooms and multiple bathrooms are best served by system and vent boilers.
Combi boilers are generally for smaller homes and flats. Because they heat water on demand, they are just not suitable for larger homes requiring more heating capacity. In a larger home the boiler has to work harder to keep interior spaces warm. Throw numerous bathrooms with tubs and showers and the typical combi boiler will probably not keep up.
Practicality notwithstanding, there are a couple of manufacturers that make larger combi boiler units usable in larger homes. They are certainly more expensive, and they start to lose efficiency as their size increases. So you still might be better off going with a system or vent boiler if you live in a larger home.
If you are like most people, price will greatly influence your purchase decision. Nobody wants to spend more than they have to. So what might you spend? If you are going with an entry level combi boiler, you’ll find they are fairly affordable. Viessmann offers a couple of smaller models ranging from £800 to just over £1,000 including VAT. Vailant and Worcester Bosch both offer combi boilers for under £1,000. Grant UK is on the higher end of the scale, with a 26-kW combi boiler at just under £2,500.
If you really want a combi boiler for a larger home, you can purchase one with additional storage. Storage combi boilers come with a built-in hot water storage tank that keeps a supply of hot water on hand so that water dedicated to the heating system doesn’t have to be diverted when you turn on the shower or run hot water from the kitchen tap.
Viessmann offers four different storage combi boilers in this category. The cheapest runs at about £870 while the most expensive is just over £1,500. The best-selling Worcester Bosch and the Grant UK models come with a price tag of about £2,100.
Shop and Ask Questions
As you can see, price variations are pretty significant depending on make and model. So how do you choose the best one? You shop and you ask a lot of questions. The worst thing you can do is call a heating contractor and choose the first model they suggest. Their recommended boiler may not be the best one for your situation.
Take advantage of all the information found online before you do anything. Familiarise yourselves with manufacturers, models, output, and extra features. If you ever come across information you do not understand, make an effort to contact the manufacturer and ask. When you are finally ready to purchase, insist that the salesperson you are dealing with compare multiple combi boilers for you so that you can see the differences.
Buying the right boiler is all about having the right knowledge. Hopefully our guide has given you enough to get started.