Don't forget these boiler jobs to do in summer

Paying your boiler a bit of attention in its off-season can set you up for a much easier time when the temperature drops and bills creep back up.

Summer is a good circuit breaker for our central heating. But don't forget about it completely - it's an opportunity to deal with wear and tear from last year. And if you find a fault, a repair isn't as urgent. A boiler repair during the winter is a nightmare; in the summer it's a dodged bullet.   

Read our checklist of boiler jobs to think about now. And if you're looking for a Gas Safe engineer, find a Which? Trusted Trader you can rely on. 

If heating is a million miles away from your mind, read our electric fan and  air conditioner buying advice to cool down. 

Turn on summer mode

Many combi boilers have modes called 'summer mode' and 'winter mode' you can access within the menu on your boiler control panel.

It's worth toggling summer mode on right now if your combi has it and you haven't already. This guarantees your combi boiler will only supply hot water and no central heating.  

If your boiler doesn't have summer/winter modes, don't fret. You can set the same thing up yourself by turning off your heating thermostat or toggling any equivalent 'hot water only' mode.

If you don't need your boiler to produce any hot water, for example if you have an electric shower and a dishwasher, or a seperate water heater, then you can turn your boiler off. And if you have an old boiler with a pilot light then it may be wise to turn that off too. 

Regardless, it's a good idea to check your heating is still working once or twice over summer. Toggle the heating on briefly and make sure the radiators start to warm up. This is especially key if you don't have a boiler service.

If you want to turn your boiler off completely and rely on an electrical water heater for the summer, read our explainer on immersion heaters to find out more.

Get your boiler serviced

A regularly serviced boiler will last longer, run more cheaply and is less likely to conk out in the middle of winter. 

One service a year is advised (and mandatory to maintain manufacturer warranties), but even if you don't regularly service your boiler, we'd recommend one this summer to make sure it's running efficiently, as gas prices will still be high over winter. You'll also lower the risk of an emergency repair. 

Summer is the best time to get your boiler serviced for a few reasons:

• You may get off-peak rates and a greater choice of engineers who aren't busy with boiler repairs this time of the year. 
• If your boiler does needs repair, it's less of an inconvenience during the hot summer months.
• You can deal with the wear and tear of the last heating season and guarantee peak performance ahead of the next one.

Getting the best boiler service

Your boiler must be serviced by a Gas Safe registered engineer. A boiler service should last at least 30 minutes  — if it doesn't, your engineer should be able to justify why. 

 During your service, the following should happen:

• A visual check of the boiler and flame
• Checks on the flue (externally and internally)
• Checking the operating pressure and/or heat input
• Checking safety devices
• Check case seals for an effective seal
• Boiler casing removed to check all main boiler components (burner, heat exchanger, main injector, spark/sensor probe)
• Boiler fired safely to identify any working faults
• Boiler parts cleaned, if necessary
• A service report showing everything the engineer has done

Afterwards, ask for a written report and check it looks right. You could end up relying on this if you try to make use of your warranty because it proves you've taken proportionate steps to look after your boiler. Your warranty terms and conditions will show the specifics. 

Flush your central heating system

You only need to do a power flush a couple of times a decade, but it's a useful way to improve efficiency and prolong the life of your boiler.

A power flush works by cleaning your boiler, pipes and radiators with a chemical mix pushed forcefully through the system. As it happens, debris, rust and scale is cleared away which lets hot water flow more freely through the loop.  

It might be worth asking your boiler engineer about doing a power flush if one of the following applies:

• Your radiators have cold spots that aren't fixed by bleeding them.
• Your boiler feels slower than usual, even if you haven't changed its flow temperature.
• Your heating is noisier than it used to be.
• You've drained a radiator and the water inside is very discoloured. 

You can bleed your radiators yourself to free trapped air if they are cold at the top and make gurgling sounds when your heating comes on. Find out how with our guide.

Fix the roof while the sun is shining

Metaphorically speaking of course, unless your roof is really broken. In which case, tend to that first. 

But more broadly, if you have gaps, cracks and draughts in your home, it's good to insulate them now, while it's an easier and less urgent job.

In fact, insulation is a two-way street. Not only does it stop your home getting cold in the winter, but when done correctly it also wards off excess heat during the peak of the summer. 

In hot weather it's good to ventilate your house when it's cooler, like at night, but lock out hot air during the heat of the day. 

Find out more: how to keep your home cool without air conditioning

If you're interested in larger insulation jobs, consider:

• Loft and roof insulation. Heat rises, so trapping it in from above is crucial. 
• Floor insulation can reportedly reduce heat loss by 15%. 
• Cavity wall insulation is useful for properties built in the last century. It's injected into the gap between your outer and inner walls. 
• Solid wall insulation can be placed in or outside a wall without a cavity. It's expensive to install, so it's a longer-term investment.  

Our insulation advice guides show you options, costs and where to start, from little jobs such as installing sealants and draught excluders to commissioning major retrofits. 

Consider new boiler controls

Some people have heating controls that are too basic to run their system at its most efficient. This is especially likely if your boiler was installed more than five years ago.

2018's Boiler Plus rules encourage the use of smart thermostats with new boiler installations. These automate some of your heating and help reduce costs by making it easier to use your controls with flexibility.

But the two best types of boiler control are known as load compensation and weather compensation. And while many smart thermostats can enable one of these controls, they don't always — and you need an engineer to set them up. 

The difference between these controls and other types is that load compensation and weather compensation change how much heat your boiler produces depending on the heat demand of your property.

Boilers are able to operate at a range of outputs. As a general rule, the higher the maximum output, the higher the minimum output. This is why getting the right boiler size is so important.  

Many smart thermostats and older programmers simply turn the boiler on and off, meaning the energy you're using isn't always proportionate to how much heating you actually need.

If you're interested, a boiler service is a good time to bring this up with an engineer. Different boilers are compatible with different systems, so you'll need a thermostat-boiler combo that gets the most out of your model.

In some cases, an engineer will recommend traditional on/off controls along other measures like making use of thermostatic radiator valves. They will need to consider the facts of your heating system to recommend the best combination of efficiency and thermal comfort.

Find out more in our guide to heating controls.

Looking for quick energy saving tips? Head to our guide to the 10 best ways to save on your energy bill.