As the mercury drops, keeping our homes warm becomes a top priority. And as the energy price cap increases, it’s more important than ever to make sure your heating system is running efficiently, or you may find yourself using more energy – and getting less warmth – for your money.

From neglecting your boiler to obstructing radiators, we reveal the common heating mistakes that could be driving up your bills.

Click or scroll on to discover how to optimise your heating system by avoiding these costly missteps this winter...

When you come home to a cold house, it can be tempting to crank the thermostat to max. However, doing so won't heat your home any quicker. Boilers work at the same speed, regardless of your thermostat settings. A thermostat simply sets the maximum room temperature, so turning it up will only result in sweltering living spaces later on and wasted energy – and money. Instead, add an extra jumper and wait for your home to reach a comfortable temperature.

Being mindful of your thermostat can really pay off. Energy provider British Gas suggests that you can save up to 10% a year by turning your thermostat down by just one degree.

It might seem logical to turn your heating off at night when you're tucked up in bed. However, you'll likely want to turn it right back up in the morning when you wake up to a freezing house. This regular fluctuation between extreme temperatures means your boiler has to work overtime to get your living spaces back up to temperature, which can put undue strain on it and potentially lead to costly repairs in the future.

Rather than allowing your heating to plummet overnight, reduce it by a few degrees instead. That way, you'll save money on your energy costs without risking damage to your boiler.

An obvious way to slash your utility bill is to make sure you're only heating the rooms you use most frequently. It doesn't make financial sense to pump heat into an attic room that's seldom used, for example. According to heating company UK Radiators, heating unnecessary rooms could cost you between £50 and £150 a year.

However, if your home is susceptible to damp, you may want to heat unused rooms intermittently to avoid costly remedial work. During a cold snap, it's also a good idea to use the frost setting on your radiators to help prevent your pipes from freezing.

A smart thermostat gives you more control over your heating, and consequently, more opportunities to reduce your energy costs. Savings claims vary between manufacturers, but British Gas says that its smart thermostat can lower heating bills by up to £175 a year.

Smart heating controls are usually linked to your smartphone, allowing homeowners to adjust their heating from anywhere. Many also come with geo-fencing functionality – this means they can track your phone's location and automatically turn your heating down when you're away and turn it up before you return home.

The location of your thermostat plays a major role in how efficiently your heating system operates. While it might seem logical to install it in a high-traffic area like a hallway, this can actually lead to unnecessary heating. When the front door opens and cold air rushes in, the thermostat may misread the overall temperature of your home and signal the boiler to fire up, even if the rest of the house is already warm.

It's best to position your thermostat in an area that isn't affected by temperature fluctuations, such as a living room, to ensure the heating only turns on when necessary. 

While there's a tendency to assume bigger is better, that's not the case when it comes to your boiler. Opting for a model with a larger capacity than your household needs will ultimately waste energy and increase your heating costs. That's because an oversized boiler produces more heat than your home can absorb in a short space of time. This can result in boiler cycling, where your boiler turns itself on and off in short intervals, which can also wear out your heating system.

Enlist a reputable engineer from the Gas Safe Register to carry out a heat loss calculation, which can indicate the right boiler size for your property.

Your boiler settings could also be inflating your energy bill, particularly your boiler's flow temperature. This is the temperature that the boiler heats water to before it's circulated to your radiators. Boilers run more efficiently with a lower flow temperature, which can save households around £65 a year according to British Gas. The optimum temperature is 65°C, which will also keep your boiler free from harmful legionella bacteria. 

You can lower the flow temperature by adjusting the dial on the front of a conventional boiler. If you have a combi boiler, simply adjust the radiator setting dial. 

Keeping your boiler in top condition is key to keeping your utility bills in check. According to UK boiler installation company Heatable, an inefficient boiler could add over 10% to your annual heating costs. That’s why a yearly service is essential, not just to maintain peak performance, but also to catch potential faults before they become dangerous.

Skipping your annual service could also void the manufacturer’s warranty, leaving you to cover costly repairs yourself. And with a full boiler replacement ranging from £2,000 to £3,000, neglecting maintenance could prove an expensive mistake.

If you have a conventional boiler rather than a combi, one of the easiest and most cost-effective ways to save energy is by insulating your hot water tank. Insulation jackets are inexpensive and widely available online or at DIY stores. The Centre for Sustainable Energy, a UK energy advice charity, says a well-fitted jacket can cut heat loss by over 75%, helping your system use less energy and money to keep your water warm.

British Gas estimates this simple upgrade could save you around £50 a year. Just make sure the jacket is at least 3cm thick for maximum effectiveness.

Over time, dirt, rust, and debris can accumulate in the pipes, radiators, and boiler of your heating system. This can lead to a build-up of thick, muddy sediment, known as sludge, which can cause obstructions, corrosion, and expensive repairs if left untreated. Sludge can also reduce the efficiency of your heating system by 15%, resulting in higher energy costs.

Enlisting a central heating engineer to clean your system can help remove the build-up and optimise your heating. This is usually done with a process known as a powerflush (pictured), in which a machine extracts dirty water and debris and replaces it with clean water.

Radiators play a vital role in your central heating system, so it's important not to overlook them. With regular use, air can become trapped inside, preventing hot water from circulating efficiently. This makes your heating system work harder and less cost-effectively. If the top of a radiator feels cold or you hear gurgling or banging noises, trapped air is likely the cause.

Fortunately, bleeding a radiator is a simple fix. First, switch off your heating and wait for the radiator to cool. Place a towel underneath, then use a radiator key to open the valve. When you hear a hissing sound and water begins to escape, close the valve. Finally, check your boiler’s pressure gauge as it may need topping up.

Radiators emit heat into your living spaces, as well as into the wall they're fitted to. When radiators are installed on external walls, this could mean losing valuable warmth in the colder months. Radiator reflectors are a simple way to save energy and money. Fitted between the wall and radiator, these metal or foil-wrapped boards help to reflect heat into the room, rather than allowing it to escape outside.

Heat retention estimates vary between brands, but according to manufacturer Radflek, its radiator reflectors redirect at least 95% of lost heat back into the room.

Restricting airflow to your radiators can make your heating system less effective and more expensive to run. Furniture placed too close to a radiator can trap heat, preventing it from circulating properly and warming the room. Experts recommend leaving a gap of six to 12 inches (15-30cm) between a radiator and any furniture to allow optimal airflow.

This is especially important if your radiators are fitted with thermostatic radiator valves, which detect the room temperature and adjust the flow of hot water accordingly. If heat circulation is blocked, the valves may not get accurate readings, resulting in less efficient heating.

With our washing lines out of use until spring, you might hang wet clothes on the radiator to help them dry quicker. But doing so can hike up your utility bills. Like obstructing radiators with furniture, drying clothes on them prevents heat from circulating properly, forcing your boiler to consume more energy to warm your home. If done regularly, this can wear out your heating system and reduce the lifespan of your boiler.

For those with thermostatic radiator controls, the obstructed airflow can also cause localised heat spots, which can trigger your radiator to turn off. Instead, stick to a trusty clothes horse.

Even with an efficient heating system, poor insulation can lead to significant heat loss and higher energy costs. According to the Energy Saving Trust, an uninsulated home can lose 25% of its heat through the roof, 33% through the walls, and 10–20% through the floor.

Most modern homes built after the 1990s include wall insulation, but many older properties with solid or cavity walls may not. While wall insulation can be costly to install, it pays off in the long run through energy savings. You can also improve efficiency by topping up loft insulation or adding insulation boards over concrete floors. Always consult a qualified installer to ensure work is safe and effective.

A more affordable way to prevent heat from escaping your home is through draughtproofing. This involves sealing gaps and cracks to reduce the energy needed to keep your living spaces warm. For instance, draught seal tape is an effective and inexpensive solution for stopping cold air from entering through voids around windows and doors. Flexible sealant or decorators' caulk can also be used to fill gaps between floorboards and skirting boards.

However, it's also important to maintain good indoor air quality. Some ventilation is essential for a healthy home, so avoid blocking wall vents, trickle vents, extractor fans, underfloor grilles, or airbricks. 

The front door is one area that’s often overlooked when it comes to draught-proofing. Cold air can seep in through unexpected gaps, such as keyholes and letterboxes, making your home harder to heat. Fortunately, there are plenty of cost-effective solutions. Keyhole covers and letterbox brush strips are cheap and easy to fit, while fabric draught excluders can block chilly air from creeping in under the door.

According to British Gas, sealing gaps around doors and windows alone could save you up to £60 a year on heating bills, making this a simple upgrade that pays for itself over time.

An open chimney can cause significant heat loss, letting warm air escape and making your heating system work overtime. If your fireplace is mainly decorative, draught-proofing the chimney is a smart way to save energy. For a long-term fix, fit a cap over the chimney pot to retain heat and keep out moisture and birds. Alternatively, use a chimney balloon or a draught excluder around the fireplace – both can easily be removed if you want to light a fire. Just be sure not to fully seal the chimney, as some ventilation is still necessary.

The Energy Saving Trust estimates that draught-proofing your chimney could save between £60 and £65 per year.

Windows are a major culprit for poor heat retention, and your choice of window treatments can exacerbate the issue. Thin, sheer curtains or voiles provide limited insulation, allowing heat to filter through their open-weave fabrics. Opt for thicker designs instead, such as thermal or blackout curtains, or Venetian blinds or shutters, which offer a more robust barrier. 

If you have long curtains that hang over your radiator, consider using tie-backs or shortening their length to sit around 1.6 inches (4cm) above the radiator. Otherwise, the curtains may obstruct the circulation of hot air, making your heating system work harder and your energy bill rise.

There's only so much insulation your curtains can provide if your windows themselves aren't energy efficient. Single-glazed windows can leak heat from your home and make living spaces draughty even when the heating is cranked up. Swapping out single glazing for A-rated double glazing can save you between £140 and £160 on your annual heating costs, according to the Energy Saving Trust.

While upgrading your windows is usually relatively straightforward, it might not be quite so simple if your home is a protected listed building. If it's not possible to replace your windows, secondary glazing, which involves fitting a pane of glass or transparent material on the inside of an existing window, may be a more appropriate option. 

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