As the Christmas holidays approached, Madeleine and Matt Cage* decided to replace their 19-year-old boiler, which suddenly only lasted 20 minutes. When the engineer came out to see what they needed, he just looked at the existing system and recommended a similar machine.
The couple quickly realized that the existing boiler, which they were told to replace with something similar, was too big for their four-bedroom home.
The second engineer, who had a more accurate idea of the size of the houses and how they used their heating, recommended a smaller system that would be more efficient and cheaper to run.
Joe Alsop of The Heating Hub, an independent energy efficiency consultancy, says oversized boilers are a common problem and it only adds to the cost of heating our homes.
As we approach the coldest part of the year, bills are skyrocketing during the energy crisis and consumers are being told there are a few simple steps they can take to achieve boiler savings.
“Each boiler has potential efficiencies, some of which can be exploited by the user with a few simple and safe DIY changes,” Alsop said.
The majority of boilers (about 80%) sold in the UK are combined units providing heating and hot water. The rest are either conventional boilers for heat only, or system boilers operating with hot water tanks.
All types have similar problems in that they are often too strong for the demands of the family. As Alsop explains, “It’s like trying to boil water in a small pot on a big stove—it just can’t help but boil.
“Boilers are most efficient when they match the heat loss,” she said. Studies have shown that very large boilers are 6-9 percent less efficient.
On cold days, the average British home can be heated with a 6-10kW boiler. Most thermal and system boilers start at 11-13 kW. Combined boilers require at least 24kW, she says, but that’s for instant water heating with a heat output of around 18kW, which is still too much for most homes.
According to Alsop, a lack of understanding of heat loss has led some installers to install larger and larger boilers, installing systems up to 50kW. A boiler that is too large is prone to wear and tear, resulting in higher fuel bills. To solve this problem, modern boilers must have two separate outlets, one for heating and one for hot water. Combination boilers automatically have this function. But with heat-only boilers and system boilers, installers have to properly set up the system and install the correct heating controls, which is not the case in most cases, she said.
When they are installed correctly, the boiler can be lowered or adjusted according to the installer’s maximum heat requirements.
The water inlet temperature determines the temperature at which the boiler heats water and is usually set between 70°C and 80°C when the combination boiler is installed. But for many boilers, that’s too much to run efficiently, according to energy company EDF.
At lower temperatures, they are more likely to go into condensation mode, so more heat can be captured and returned back to the system.
According to Nesta, an organization that promotes innovation, combi boilers generally work best with radiators heated to 60°C or lower. This does not mean that the temperature in your house will be lower, but the radiator will take a little longer to warm up.
You can adjust it yourself, but it’s not the same as changing the temperature on a thermostat. The controls for changing the supply water temperature are located on the front of the boiler.
“A government report has shown that 70 percent of homes can be kept warm at a supply temperature of 60°C, which is 20 degrees lower than most homes currently have,” Alsop said.
“If residents pay special attention, they can raise the temperature to 50°C during the warmer months and return it to 60°C when it gets colder to match the temperature outside.”
Since the combi boiler is usually placed at some distance from the bathroom, it may take some time for the water to reach the faucet.
The pre-heating function of some machines allows you to prepare a small amount of hot water at any time, which can be quickly directed to the hot water tap.
But for this, the boiler must be turned on every 90 minutes or so, using a small amount of gas at a time. This adds up over time: Heat Hub says you can save up to £90 a year if you turn this off.
The method of disabling depends on the type of machine, not all models have this function, and some cannot be disabled.
Changing the way you heat your home can save you a lot of money. Turning the thermostat off even one degree can save money. In France, private house owners are advised to lower their thermostats to 19 degrees Celsius when they are occupied and to 16 degrees Celsius at night.
“It’s always a bit of a stretch. But it works. Going from 20°C to 19°C is one of the biggest savings,” says Alsop. The degree alone is said to save £117 a year on average bills.
Some homes keep their boilers “long and low” or at a lower temperature throughout the day, so the machine has less work to do and spends more time in low efficiency mode trying to reach a certain temperature, not enough.
However, Alsop says it has been proven to use more gas and timed mode, where the boiler is turned on for a set period of time, say two hours, is more efficient, saving £130 a year.
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Post time: Mar-24-2023