Most of us don’t give our heating system a second thought once the summer months arrive. The radiators are off, the evenings are lighter, and the boiler is left ticking away in the background.
But ignoring your boiler during the off-season can cause problems when you really need it. Regular boiler maintenance, especially in spring, summer and at the start of Autumn, is a good move to make sure your home is safe and ready for the cold winter months.
Let’s look at what happens when your boiler sits unused, whether you should switch it off, and why a boiler service in the summer can save you hassle and money later.
What happens to boilers when they’re unused?
A boiler is made of many moving parts, including valves, pumps, seals, and heat exchangers. Like any mechanical system, boilers can run into various issues if it is unused for extended periods, including:
| Issue | Likelihood | Cause | Effect |
|---|---|---|---|
| Pressure loss* | Common | Natural seepage or small leaks in the system | Boiler struggles to heat water properly, and radiators may not get warm |
| Trapped air | Common | Air entering the system through valves or joints | When switched back on, you may get uneven heating, cold spots on radiators and noisy pipes |
| Sticking valves or pumps | Occasional | Lack of movement | Reduced circulation, poor boiler performance, risk of breakdown |
| Corrosion inside components | Occasional | Moisture and inactivity leading to rusting | Reduced boiler lifespan, potential leaks or breakdown |
| Seized parts | Less common | Lack of movement | Boiler may fail to start or make strange noises |
| Carbon build-up | Less common | Incomplete combustion when boiler is rarely fired up | Reduced energy efficiency, risk of safety issues if unchecked |
*Your boiler’s pressure gauge should sit in the green zone between 1.0 and 1.5 bar when the system is cold. If the pressure drops below 1.0 bar, it might not work properly, and it could cut out to protect itself. A reading of 0.5 bar or lower usually means the boiler won’t fire at all. That’s considered very low and will almost always need topping up straight away.
It’s essential to keep your boiler well-maintained, even in the summer, to ensure you avoid these issues.
Should I be switching off my boiler during the summer?
It’s a common question: should I switch my boiler off when it’s warm? The answer depends on your setup.
For most homes, leaving the boiler on but turning off the central heating function is the safest and most practical choice. This keeps hot water available while reducing wear on the heating system.
If you switch your boiler off entirely, not only will you cut off your hot water supply, but you may run into any number of issues, as detailed in the table above.
If you’re concerned about energy costs, remember that modern boilers are designed to be energy efficient. Running your boiler in the background to supply hot water will not cause a dramatic rise in energy bills, especially compared with potential repair costs.
Is it time for a new boiler? Read our guide on how to choose the right boiler for you.
Can you keep your hot water on and radiators off?
Yes, and this is what most households do. You can set your controls so the boiler heats only the hot water cylinder, leaving the radiators off. This way, your boiler is still functioning properly without wasting energy on unnecessary heating.
Keeping the hot water active also gives you peace of mind that the boiler is working correctly and allows you to spot any strange noises, smells, or boiler issues early.
Prompt repairs of minor issues are always easier, safer, and more cost-effective than dealing with unexpected breakdowns, especially as the weather gets colder.
Why you should do your annual boiler service in spring or summer
An annual boiler service is an essential task for every homeowner, and most boiler warranties depend on it. Choosing to book a service in the off-peak season, rather than waiting for when it gets cold, has many benefits:
Beat the rush
In the colder months, heating engineers are naturally busier. When everyone suddenly switches their boiler on and finds out it’s underperforming, appointment slots quickly disappear. By booking in spring, summer, or even early Autumn, there is more availability and a quicker turnaround.
Cost savings
A thorough inspection during the warmer months can uncover small faults before they become major problems. Something as simple as a sticking valve or low boiler pressure can cause bigger boiler issues if ignored. Regular servicing keeps boiler components in top shape and prevents costly repairs.
Keep your home safe
Boilers that are not properly maintained can pose a serious safety risk. Carbon monoxide poisoning from undetected leaks is rare but dangerous, and gas leaks can put your household in immediate danger. Annual boiler servicing ensures your system is thoroughly tested for safety and operates efficiently and safely throughout the year.
Boost energy efficiency
Whether you have a new or older boiler, regular maintenance keeps the system working efficiently and helps reduce wear and tear. Proper maintenance ensures optimal performance and lower energy costs throughout the winter season.
Protect your warranty
Many manufacturers insist on an annual service to keep the warranty valid. Skipping annual maintenance could leave you unprotected if the boiler develops a fault. A properly maintained boiler is less likely to suffer major problems, but if it does, your warranty gives you added security.
Book now and be winter-ready
The warmer months are the perfect time to book your annual service, with more availability and a faster turnaround. Booking a service now can also catch minor issues before they escalate, providing peace of mind and saving money on potential repairs.
At JPS Plumbing, Gas, and Electrical, we understand the importance of having a reliable, safe, and winter-ready heating system. We serve homes and businesses in Winchester, Southampton and beyond – book your annual boiler service today and step into autumn and winter with confidence.
Final thought
Boiler maintenance might not be at the top of your to-do list while the sun’s blazing, but it’s a smart decision to book a service, especially if you decide to turn your boiler system off. When left idle, your boiler’s components can suffer, meaning your system may struggle to work properly when it’s switched back on.
By booking a summer service, you can be confident that your heating system will function properly as cold temperatures creep in.