BOILER BUYERS GUIDE

You’re about to make a big decision. The boiler you choose should be with you for 15 years or more, so it’s important to consider your options very carefully. We’re here to give you the best advice to make the right choice, even if that means you don’t buy your boiler from us.

Type of boiler

There are 3 basic types of boiler, which are available in gas or oil:

Combi boiler – directly heats both your heating and hot water

Heat only boiler – just heats the water to be supplied to your radiators and the hot water cylinder in your airing cupboard.
​
System boiler – similar to a heat only, but it contains the circulator pump within the boiler. It also allows for the small header tank in your loft to be removed.

Size of boiler

Your house will have a certain amount of heat loss. Your system and boiler should match this rating to ensure they work most efficiently. Oversized boilers are inefficient as they deliver too much energy for the size of the system. Undersized boilers are ineffective as they won’t give you enough heat to make up for your house’s heat loss.

Ideally you should have a detailed heat loss survey on your house to ensure you’ve sized the boiler correctly. This obviously adds to the cost but may save you money in the long run. Most companies just look at the number of bedrooms and bathrooms in your house, then use their judgement on the boiler capacity. This method almost always results in oversizing.

​Boiler output is given in kilowatts. The higher the kilowatt output, the more expensive the boiler will be.

Preferred brand

The quality of the boiler is the biggest determining factor in the cost of replacement. You can get some very cheap nasty boilers, which we do not fit and would never recommend. You’re entering a world of pain if you choose to fit a Ferroli, a Biasi, or something similar.

At the high end, you have brands such as Worcester, Vaillant and Atag. These companies have built a reputation for reliability and build quality.

Somewhere in the middle sit brands like Ideal and Baxi. If you’ve bought a new build house in the last 10 years, the chances are, it has an Ideal boiler.

​All boiler manufacturers offer some kind of reward scheme to their installers, so many companies will steer their clients towards their preferred brand. It’s wise to ask the engineer or sales person about other potential options.

Type of flush

You have a choice of 3 here. A full powerflush, a chemical cleanse, or a mains pressure flush.

A proper powerflush will take a full day to complete. It’s unlikely that any boiler quote you receive will include this.

A chemical cleanse is often used when new boilers are fitted. The engineer will add a cleaning chemical to the system and let it run for a while before draining the system to remove the dirty water. This is by far the cheapest option, but doesn’t clean the sludge out of your radiators very effectively,

​A system called Thoroughflush is sometimes used as an alternative to powerflushing. This uses mains-pressure water to clear debris from your system. It can target each radiator individually but takes a fraction of the time of a full powerflush.

​Controls

Thermostats and programmers vary widely in quality.

Recent regulations require new systems to be fitted with higher efficiency controls. The most efficient controls use a system called OpenTherm. The control communicates the energy demand so the boiler can adjust its gas consumption and water temperature accordingly. These controls can often adjust heat output on the boiler according to outside air temperature, reducing heat demands in spring or autumn when the weather is mild.

With most boiler makes, you have to use the manufacturer’s own controls to benefit from this system.

​Smart thermostats, such as Hive or Google Nest also meet efficiency regulations and can be fitted to all systems. In most cases, they do not connect to your boiler using OpenTherm, so can only tell your boiler to turn on or off, making them less efficient.

​Installer

Perhaps the hardest decision of all when buying a new boiler.

Most people rely on recommendations from friends and family to choose their installer. You’re more likely to get the personal touch from a local company. It also means that if any issues arise, you’re more likely to speak directly with an engineer. Checking reviews on Google or Facebook will give you a good idea of the reliability of these local companies.

​Some people opt for the perceived safety of a big company like British Gas or BOXT. This gives you the security of a large network of engineers, but the personal touch is lost. Should any problems occur, you’ll be calling a non-technical call centre operative.

​Like all large purchases for your home, choosing the right boiler is a big decision that will affect your home for many years. It’s important to research your options thoroughly and seek expert advice.