Boiler Plus regulations explained

The short answer

Since April 2018, every gas boiler installed in a home in England must be fitted with time and temperature controls: a way to set when the heating comes on, and a way to set how warm the home gets. If the boiler is a combi, it also needs at least one extra energy-saving measure from this list:

• flue gas heat recovery
• weather compensation
• load compensation
• smart controls with automation and optimisation

Your installer chooses the measure with you and fits it with the boiler. It is part of meeting Building Regulations, so it is not optional, and it should appear on any quote for a combi boiler installation.

Time and temperature controls

This part applies to every new gas boiler, whatever the type. Time control is a programmer or timer that switches the heating on and off at set times. Temperature control is a room thermostat that turns the heating off when the home reaches the temperature you have set. Many modern thermostats do both in one unit, and a smart thermostat does both with an app.

The idea is simple: a boiler that runs only when you need heat, and only until the home is warm, uses less gas. Most homes already have something like this, but an old dial thermostat or timer may need replacing to work with the new boiler.

Where the thermostat goes matters as much as which one you choose. It should be in a room you use, away from draughts, direct sunlight and heat sources such as a radiator or the kitchen. A thermostat in a cold hallway keeps the heating running long after the living room is warm. Ask your installer where they plan to put it.

The four options for a combi

A combi needs one of these four measures on top of time and temperature control. Here is what each one does.

• Flue gas heat recovery: a unit fitted with the boiler that captures heat from the hot flue gases and uses it to pre-warm the cold water coming in for your taps. It needs a compatible boiler and some extra space.
• Weather compensation: an outside sensor tells the boiler how cold it is outdoors. On milder days it runs the radiators cooler, which keeps a condensing boiler working efficiently.
• Load compensation: works on a similar idea using the temperature inside. As the room gets close to the set temperature, the boiler turns down its flow temperature rather than switching on and off.
• Smart controls with automation and optimisation: a smart thermostat that learns how long your home takes to warm up and starts the heating at the right moment, rather than earlier than needed.

Which suits you depends on the boiler, how you like to control your heating and whether you want an app. A smart thermostat is the option most people have heard of, but it is worth asking about the others too.

System and regular boilers

If you are fitting a system boiler or a regular boiler, Boiler Plus requires the time and temperature controls, but not the extra measure that a combi needs. You can still choose to add one. Weather compensation and smart controls work on these boilers too, and many people find them worth having.

Your installer will check what controls are already in place, whether they will work with the new boiler, and what needs adding. Ask them to explain anything that is being replaced and why.

What it means when you buy a boiler

Because the controls are a legal requirement, they should be part of the price from the start. When you compare quotes, check that each one names the controls being fitted. If a quote for a combi doesn’t mention a smart thermostat, weather compensation or one of the other options, ask which measure is included.

• Ask which controls are included and how they meet Boiler Plus.
• Ask whether they will be set up before the engineer leaves, including any app.
• If you already have a smart thermostat, ask whether it can be reused with the new boiler.
• Ask for the controls to be shown to you at the handover, so you actually use the features you are paying for.

For more on the options and how they connect, see smart thermostat installation.

Common misunderstandings

• “Any app thermostat will do.” For a combi, a smart thermostat only meets the rule as the extra measure if it provides automation and optimisation. Ask your installer to confirm the model they fit does.
• “I have to replace my controls now.” Boiler Plus applies when a boiler is installed. It doesn’t require changes to a boiler that is already in place.
• “It only matters for the paperwork.” The controls are part of meeting Building Regulations, which is confirmed when the installation is notified through the Gas Safe Register. They also make a real difference to how much gas the boiler uses.
• “The controls have to be the same brand as the boiler.” Not necessarily. What matters is that the controls are compatible with the boiler and set up properly. Some features, such as compensation, rely on the controls and boiler being able to talk to each other, so ask.

If you are ever unsure whether a quote meets the rules, ask the installer to explain in plain terms which part of Boiler Plus each control covers. A Gas Safe registered installer should be able to answer that easily.

Getting the benefit from your controls

Controls only save gas if they are set up and used. The biggest gains usually come from a lower flow temperature, which lets a condensing boiler recover more heat from its exhaust, and from heating schedules that match when you are actually home. Our guide on boiler flow temperature explains how to set it.