Improve your heating’s efficiency
Get your system up to scratch now – well in advance of winter – and you’ll reap the benefits on your energy bills, says Chris Bates
Boost your boiler’s performance before the winter chill
When Britain enjoys a long, hot summer, we understandably want to soak up every drop of it. I wouldn’t want to shatter the illusion, but by the time you’ve picked up this edition of Build It in the shops, we could be as little as a couple of months away from the start of the heating season.
Now is actually the perfect time to check over our central heating systems and look at ways to improve performance, before we actually start paying for the gas or oil we use. But for many of us, it’s a case of out of sight, out of mind when it comes to our boilers. Of course, you’ll always be using yours to provide domestic hot water – but the problem is that the unused parts of the system can collect dirt, limescale and other issues since they were last used.
Years ago, I was caught out myself when the motorised valve (the bit that controls the flow of heated water) seized up the first time I tried to get the radiators going. Cue three days waiting in the cold for a plumber to come out, plus a £200-odd bill before I even started putting warmth into the leaky old Victorian cottage I lived in at the time!
And I’m not the only one: according to a recent survey by Worcester, Bosch Group, one in five of us have never had our boilers serviced. “From checking our car MOT to updating antivirus software on our computers, we regularly ensure the important appliances around us are working to our best,” says Martyn Bridges, director of technical communication and product management at Worcester. “Unfortunately this attitude doesn’t stretch to boilers – despite the fact they are on day in, day out throughout the year – and they’re largely forgotten about until they actually stop working.” So, what can you do to make sure your boiler-fired central heating is in top shape; and how can you improve its efficiency?
Give it a test run
The simplest way to avoid getting into the same situation I did is to run the system for an hour or so in the early autumn, before the weather turns. This will give you a chance to check everything’s in order with the central heating before you actually need it in earnest. Check for obvious signs of issues: do the radiators come on properly (with no cold spots), for example; is the pressure on the boiler right; and are there any signs of leaks from the emitters?
Service annually
Your central heating consists of a whole bunch of components and materials, all with water running through them. Over time, sludge, limescale, air and even corrosive chemicals can build up in the system – reducing efficiency and potentially causing more serious damage.
A yearly service from a suitably qualified OFTEC or Gas Safe engineer shouldn’t cost more than around £70-£80 in most parts of the UK, which is pretty good value if it extends the life of the boiler (and it may be a necessity for any guarantee you have on a new appliance). Typically, this will involve a visual inspection of the boiler, seals and gaskets; operating pressure and/or heat input test; flue and ventilation inspection; safety check; and cleaning of parts (if required). Note, however, that you’ll have to pay extra for any follow-on services, such as repairs or power flushing.
Bleed the radiators
A simple DIY job (see www.self-build.co.uk/bleed-radiators), this can make a big difference to performance, so it’s worth undertaking several times over the course of the heating
system. The aim, as you’re probably aware, is to remove air pockets from the emitter circuit. These can not only cause cold spots on your radiators, but they’ll reduce efficiency and could even lead to corrosion. If you notice any discolouration in the water – either whilst bleeding the radiator or through evidence in old leaks – then the system is almost certainly overdue a clean (see the next paragraph for more on this).
Flush it out
Sludge, limescale and corrosive material will inevitably build up over time. The longer you leave it, the more inefficient the system will become – and the greater the risk of components failing. Tell-tale signs of an issue include the presence of reddish or (even worse) black particles in the water you bleed from radiators or any corresponding leaks.
In the UK, the preferred way to clean a central heating network suffering from this kind of problem is power flushing, which is always best left to the professionals.
For an average three-bed home, you can expect to pay around £300-£450 for this service – although the price is very much dependent on the number of radiators in your home. The engineer will need to use the appropriate cleaner to deal with the issue at hand and the age of the system. Note the process can open up leaks in degrading components, as sludge, rust and debris previously hiding the problem gets removed. These will need to be replaced.
Rebalance the system
If you find that radiators located further away from the boiler aren’t getting as hot as you’d like them to, the setup may need rebalancing. The basic idea is to increase resistance at emitters closer to the appliance by tightening the lockshield valves as required, so that the heated water flows throughout the whole house. You can do this DIY (www.boilerguide.co.uk has a handy step-by-step) but you may prefer to leave it to an engineer.
Fit thermostatic radiator valves
Most of us are familiar with TRVS; the self-regulating valves that change the flow of hot water into a radiator – allowing you to have control over the temperature in different zones in your house. Given that good-quality manual versions can be bought for around £20 each, it’s surprising how many homes still don’t have them. These days, digital models are available from the likes of Honeywell that can be hooked up to intelligent controls. They don’t come cheap, but they can be a good upgrade option for renovators who want more control over their energy usage.
Note that TRVS should never be fitted in bathrooms, because the heat from your bath or shower will shut the radiator off just when you need it to stave off condensation. You should also avoid fitting them in the same room as the main thermostat, as they will fight for control over the boiler.
Set the thermostat right
You’ve probably seen both the heating industry and the media harp on about this for many years, but it’s a fact that dialling your thermostat down by just 1°C can save as much as 10% off your annual heating bill – without affecting your cosiness factor. “Something between 18°C and 21°C should be plenty to ensure your home maintains a comfortable temperature throughout,” says Martyn.
Replace your old boiler
If your appliance is over 15 years old, you could be wasting as much as 30 pence out of every pound you spend on warming up your home and domestic hot water – and with it dramatically increasing your household’s CO2 emissions. “For an average home, as much as £235 could be escaping through the flue each year,” says Martyn.
At that level of potential savings, replacing a very old model with a high-performance modern version becomes a no brainer. Since April 2018, all new gas boilers installed in the UK have been required to deliver a minimum efficiency of 92% under the European Union’s Energy-related Products Directive. Time and temperature controls must be fitted to all new oil and gas appliances, and any combi installations must include at least one additional energy efficiency solution (either flue gas heat recovery, weather compensation, load compensation or intelligent controls).
Switch to smart controls
Given the high operating efficiency of modern boilers, in many ways improving performance and cutting bills is more about a household’s usage patterns and controls rather than the nuts and bolts of the system. Fitting (and correctly using) a standard programmable timer with thermostats and TRVS will get you three-quarters of the way there in terms of the potential savings. But if you want to go the whole hog, you’ll need to go a bit more hi-tech.
The latest smart systems can give you complete oversight of the internal climate of your home, with full zoning, ultra-detailed scheduling, weather pattern sensors and swipe-of-a-phone-screen mode changes to help you attain maximum levels of comfort and efficiency. “Recent research from Salford University showed that savings of up to 40% are possible on a well-controlled heating system over an uncontrolled one,” says Martyn.
If you’re the type of person who runs around the house all day adjusting each radiator valve, you won’t see such a big benefit – but the fact everything is automated and intelligently compensates for external factors means you’ll certainly have a lot more time on your hands.