MT150512If everyone in the UK upgraded their old boiler, we would save £1,775 million and 13.12 tonnes of CO2 per year*

There are myriad systems out there to heat your home, and with fuel costs spiralling and carbon emissions to cut, it’s important to choose wisely. Our guide is the best place to start

As the worst of the winter stretches out before us, the UK’s 20 million central heating systems will have been dusted down, fired up and are being put through their paces. But as well as keeping the nation warm, each of these trusty machines is also generating by-products, many of which, such as carbon dioxide (CO2), are undesirable. Older, fossil fuel-based systems like oil and coal are the worst offenders, whereas the best of the new systems, such as biomass, can boast zero carbon emissions. There are 1.5 million boiler replacements in the UK a year, so what’s the best option? We examine the different fuels on offer to heat your home, the best appliances to choose and how your energy bills and carbon emissions will be affected by your choices.


The best, cheapest option for homes ‘on the grid’, but you could still save energy by upgrading to a better boiler

We’re big consumers of natural gas for heating – 77 per cent of central heating systems in the UK are powered this way. For households on the mains gas grid, gas is still the most cost-effective fuel for heating. And energy efficiency is much improved. Building regulations now specify that all new boilers in England, Wales, Northern Ireland (and Scotland from May 2007) must be highly efficient condensing boilers, which convert over 90 per cent of their fuel to heat. Check any boiler’s SEDBUK efficiency rating on boilers.org.uk, or look out for energy saving product labels issued by the Energy Saving Trust (est.org.uk). ‘There’s no excuse not to select an A-rated boiler when replacing an old one,’ says Ian Byrne of the National Energy Foundation. These are more expensive than a conventional boiler with 66-81 per cent efficiency, but you’ll save around a third on your heating bills, and more if you upgrade the controls (see box on p140).

MT150614Registered CORGI installers (who by law must install gas appliances) can source suitable condensing boilers. Market leaders are Baxi, Potterton, Glow- worm, Ideal, Saunier-Deval, Vaillant and Worcester. Ask the installer to calculate the correct size, based on the size of your home and its insulation.

So, is gas best? ‘Gas is the cheapest fuel,’ says Richard Macphail of the National Energy Foundation, ‘and it’s also much greener than its main competitor, oil.’ Of the fossil fuels, it’s the cleanest: according to Defra, gas has a carbon dioxide output of 0.19kg per kWh, lower than 0.214kg for liquid petroleum gas (LPG) and 0.24kg for oil. Yet this is still much higher than using biomass or a ground source heat pump.

In the future new-build homes should even strive to dispense with central heating completely, according to Zoltan Zavody of the Energy Saving Trust. ‘In Germany, Passive Houses (passiv.de) are so well built, without the gaping holes we leave during the construction process, and fully insulated, that they don’t need central heating. Panel heaters are sufficient for a few cold days a year. That’s what we need to start doing here.’

Be aware that prices of all heating systems can vary hugely, depending on manufacturer, the size of your home, the type of fuel and boiler you choose, and the cost of installation. Prices quoted here do not include installation and this adds a significant and unavoidable chunk. The best approach is to research various boilers or systems, then check the manufacturers’ websites or trade bodies (CORGI, OFTEC, GSHPA) to find registered or recommended installers in your region. Contact an installer to obtain a specific quote based on your home. The installer will source the correct boiler from a builder’s merchant. Don’t attempt to install it yourself.




Most expensive to run, but can be cost- effective for small, snug properties

Electric storage heaters tend to be more expensive than other systems. However, as gas prices rise, storage heaters are increasingly viable for small, well-insulated properties. They’re cheaper to install, but more expensive to run. Panel heaters now tend to be installed in bedrooms, offering better warmth.

The cheap off-peak electricity (such as Economy 7 or White Meter) that storage heaters use to heat bricks overnight is priced in line with mains gas, but some peak (ie costly) usage is usually inevitable.

The best modern storage heaters have a charge control, which automatically adjusts the amount of heat stored overnight according to room temperature. This is energy- efficient, but the way electricity is generated, often by burning coal, is not green. For every watt you use, up to three must be generated to transmit it to you. A solution is to use a green tariff, from a firm like Ecotricity (ecotricity.co.uk). Compare suppliers on whichgreen.org.

MT400215Oil and LPG

The most costly of the fossil fuels have high emissions too – use as a last resort

‘Oil and liquid petroleum gas (LPG) are becoming redundant. We’re about to reach peak global oil supply, so demand will start to exceed supply, and prices will rise,’ says Kirk Archibald of the Energy Saving Trust. For homes off the gas grid, oil (kerosene) and LPG have been traditional choices. Installing an oil or LPG boiler is cheaper than a biomass boiler or ground source heat pump, but running costs and carbon emissions are much higher.

Both oil and LPG condensing boilers are an improvement on a solid fuel system. Modern oil systems are very efficient, so it’s best to wait until your boiler is due for replacement before swapping it.

Pricewise, LPG has become cheaper than oil, but both are fairly expensive, partly because you have to pay delivery costs. Both require a large storage tank, which is a planning consideration. If you’re doing a new-build or replacing a solid fuel system, only choose oil or LPG if biomass isn’t available.

Try these: Grant Vortex Utility System oil condensing boiler, 97.0 per cent efficient; Atlantic 2000 R22/40 oil condensing boiler, 94.2 per cent efficient; Vaillant Ecomax 613/2E LPG condensing boiler, 93.3 per cent efficient; Keston C55 LPG condensing boiler, 93.3 per cent efficient Initial outlay £3,000 and upwards Annual running cost £893 Green verdict 2/5

ENERGY SAVING The logical approach to reducing energy usage in your home is to conserve heat first before overhauling your heating system. Prioritise fitting insulation and modern heating controls. Take the Energy Saving Trust’s Home Energy Check: either online (est.org.uk) or obtain a paper version from your local Energy Efficiency Advice Centre (0800 512 012). They give free, impartial advice on making your home more energy-efficient. You must carry out energy- saving measures before applying for any energy-saving grants.

INSULATION It’s no use improving your heating if your insulation isn’t up to the job. So top up your loft insulation, insulate cavity walls and seal off any draughts. Double glazing will also keep in heat. Read our Eco feature (on page 112) for more advice.

MODERN CONTROLS Heating controls can be upgraded any time, so when you are getting your boiler serviced it should not cost much more to fit a good timer. Recommended controls, all of which will save you money, are: Separate boiler controls for heating and hot water Thermostatic radiator valves Room thermostats Zone control – two or more thermostats, for large houses Weather compensated controls – these measure the ambient temperature and delay turning the heating on in the morning according to the weather


A carbon neutral fuel that’s best for the environment

‘If you’re off the gas main, that’s usually because you’re in the sticks,’ says Richard Macphail. And sticks burn. ‘In the countryside there’s always someone nearby generating biomass fuel, usually wood pellets.’ Although burning biomass creates CO2, this is carbon that the tree has absorbed during its lifetime, so biomass is carbon neutral.

‘A biomass boiler can cost a lot to install, but the annual savings of £300-£350 a year compared to oil, LPG or electricity means it will pay for itself over 10 years, and it should last for 20. There’s a significant annual saving of six to seven tonnes of CO2 too,’ says Kirk Archibald.

Biomass systems are easy to install in existing homes and new-builds. Stand-alone stoves (with a 6- 12kW output) heat a room, and higher output versions can also be attached to a back boiler to run central heating or heat water. Separate boilers, the size of a large oven, run on logs, woodchips or pellets, but pellet versions are best as they have an automatic feed. Compacted wood pellets have a higher energy value than logs or woodchips, so they’re more expensive but are easier to handle.

At around £5,000, biomass boilers are comparatively costly, but the Low Carbon Buildings Programme offers grants for 30 per cent of the cost (up to £1,500) – apply in advance. Prices of biomass stoves are around £1,500-£3,000, and grants are available to subsidise up to 20 per cent of the cost.

Make sure you fit the correct flue, which must comply with Part J building regs, and you need planning consent for Areas of Outstanding Natural Beauty or listed buildings. You need ample storage space for fuel, and also check which appliances are permitted in smoke control areas (for details see uksmokecontrolareas.co.uk)

‘You have to watch transport costs. It’s no good having biomass delivered from Scotland if you’re on the south coast of England, or the transport impact will shatter your green credentials,’ says Richard Macphail. Check logpile.co.uk to find a supplier within a 25-mile radius.

Try these: Kunzel pellet boiler; RIKA Evo Aqua pellet stove; Wamsler Inga pellet stove

Renewable energy

Generating your own renewable electricity to power your heating is increasingly viable. Products like domestic wind turbines, solar water heating or photovoltaic panels are growing capable of powering a boiler or panel heaters. Micro combined heat and power (CHP) units, which are domestic- scale plants that generate electricity and heat, are currently on UK trial. If successful, carbon-free heating may become available within the next few years. ‘Homes will always need to rely on the grid in winter, but the electricity you generate in summer can be sold back to the grid,’ says Kirk Archibald. Installation grants are available from the Low Carbon Buildings Programme, which also has a useful list of suppliers on its website.

Ground source heat pumps

A major installation, but offers huge savings on running costs

Latent heat from the ground is extracted via a borehole or network of submerged pipes in your garden. A unit the size of a fridge-freezer is installed inside. These systems are usually efficient and trouble free, relying only on an electrical pump. But, if there is a problem it can be a big problem, as boreholes are deep and pump failures or flow problems can be costly. Can be carbon neutral if you use a renewable energy source for the pump, such as wind or solar.

Ground source heat pumps are advisable for a new- build or significant conversion, but not really sensible for retro-fitting. Putting in boreholes or underground pipework is less feasible in cities. ‘GSHPs don’t work well with existing radiators as the temperature they generate – 50°C – is too low. What this does suit is underfloor heating,’ says Ian Byrne (see box below).

Installation is much more costly than an A-rated gas boiler, but the running costs are comparable, and the green credentials are far greater, saving 4.5-5.5 tonnes of CO2a year.

This is a promising option for the future. ‘Ground source heat pumps are a nice technology that’s already common in Scandinavia, and they’re now enjoying good market growth here,’ says Kirk Archibald. ‘It’s a way to get your carbon footprint right down.’

Try this: Worcester Greenstore ground source heat pump; Kensa compact heat pump



Words Fiona Sibley

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