A Beginner's Guide to Home Heating
With the huge increase in fuel costs in recent years, along with new government incentives favouring renewable energy, choosing your heating system is more important than ever.
CONSIDERATIONS FOR HEATING SYSTEM
The way you live will have a major effect on your heating needs. Typically, a working family’s requirements for instant heating early and late in the day will contrast with a retired couple’s requirement for steady, background heat throughout the day.
YOUR HOME DESIGN
A well insulated new home with family bathroom and single en suite may suit a fairly standard combination boiler set-up, whereas a barn conversion with multiple bathrooms will place very different demands on the heating system.
SET UP COSTS
The cost of the installation, including labour and materials, will vary greatly from system to system. Some of the greener systems have high initial costs as they have yet to benefit from the economy of scale available to the mass market producers of gas boilers. However, some have very attractive incentives under the government's proposed Renewable Heat Incentive which is due to come into practice next April.
This is perhaps the most difficult aspect of choosing a system. If you possess a crystal ball, then now’s the time to use it! The open energy market that we now enjoy makes establishing today’s energy costs difficult enough; predicting future costs is all but impossible. Even the costs of one fuel relative to another are difficult to forecast – so levels of energy efficiency may be a better criteria.
This is a little easier to predict, although there may be question marks over some of the newer technologies, making solid manufacturer’s warranties essential.
Do you want to see traditional radiators? Are power showers a must? Will you cook on a range? All these can influence the logic behind your choice of heating system.
FUEL AVAILABILITY AND STORAGE
Sadly, not all of us are at the end of a gas pipeline and while there are usually suitable alternatives in most situations, it is best to establish what your realistic options are early-on.
Before choosing any heating system it is worth analysing government incentives for particular systems. Last year the government introduced a boiler scrappage scheme which made it attractive to replace old inefficient models. Sadly that scheme has come to a close. However, there are still other schemes around, especially for installing renewables, such as solar, photovoltaics and wind turbines. The current Feed-In tarrifs offer good returns for producing 'green' power. Next April, the proposed Renewable Heat Incentive scheme will make it even more attractive to install renewable systems, especially biomass boilers.
CHOOSING WINTER FUELS
Despite the upsurge in popularity of renewables, most central heating systems are gas-fired. All new gas boilers are condensing models. This means that the hot flue gases pass through a heat exchanger to pre-heat cold water entering the boiler. The result is an efficiency of around 90 per cent compared with around 70 per cent for conventional boilers. ‘Condensing’ comes from the fact that the flue gases are now so cool the water vapour they contain condenses into steam. Efficiency can be improved even further by a modulating burner, which can adjust the boiler flame automatically depending on the demands placed on it. The main choice in boilers is between a straightforward condensing model and a combination, or ‘combi’ boiler. A combi is effectively an instant water heater. The water is heated up only on demand using an additional heat exchanger inside the boiler. As a result there’s no need for a separate hot water cylinder, a cold water or expansion tank in the attic or all the associated pipework. This makes it much easier and quicker to install, one reason why professionals have pushed it; combis now account for over half of all boiler sales. A further advantage is that the system is sealed so that water comes out of the taps at mains pressure. The main drawback is that only relatively small volumes of water can be heated at one time, so flow rates can be slow, and get even slower if two hot taps are operated at once. Combis are most suitable for flats and smaller houses; in a large family home their limitations are likely to be exposed very quickly. A third type of boiler, known as a ‘system’ boiler, combines the virtues of the two. It uses a full-size storage cylinder – thereby guaranteeing a plentiful supply of hot water – but, as with the combi, the system is sealed, giving mains pressure throughout the house. A system boiler can also incorporate all the main components, including storage, pump and programmer, in a single unit, making it as easy to install as a combi.
- Sticking to the tried and tested is generally a safe bet with the biggest pool of professionals if anything goes wrong.
- Gas is clean, easy to obtain and efficient.
- Boilers are compact, and can be easily incorporated in a kitchen.
- If you’re not on mains gas, installation costs can be expensive.
- The complexity of modern condensing boilers makes annual servicing essential.
- Fluctuating prices make budgeting difficult.
This again is a popular option with around 1.5 million house-holders using oil-fired boilers for central heating. As with gas, prices have fluctuated wildly in recent years, and look set to continue to do so – albeit in a generally upward direction. One of the advantages of oil is that it can be bought in bulk when prices are at the bottom of the cycle (summer).
This is also its main disadvantage since you will need to install a large storage tank, typically between 1,000 and 6,000 litres, depending on the size of your home. Currently, tanks have to be sited at least 1.8metres from the house and 760mm from a boundary. If over 2,500 litres they should also be double-skinned. It’s no surprise, then, that most oil-fired systems are found in rural areas where space is less restricted. Oil-fired boilers, which can be both condensing and combi, are more efficient than gas, but cost around 25 per cent more.
- You can set your budget by buying in one go.
- The growth of biodiesel promises cheaper and more stable fuel supplies.
- Storage tanks are expensive.
- Space and tanker access is also required.
- Tanks can look unsightly.
LIQUID PETROLEUM GAS (LPG)
Most of us are familiar with portable Calor gas cylinders used for caravans and boats, but LPG can also be used for full-scale central heating systems. It gives a cleaner burn than heating oil but is more expensive. It’s also more volatile. As a result, storage tanks must be sited at least 2.5 metres from the house and boundaries – further for larger tanks – though distances can be reduced by erecting a protective fire wall. Fortunately, LPG suppliers will install the tank for you and provide regular maintenance. LPG boilers cost up to 15 per cent more than gas models, but gas models can be converted.
- Self-sufficiency of oil with convenience of mains gas.
- Can also run cookers.
- Outside space is essential.
- Can look unsightly.
Real fires have an enduring appeal, but traditional solid fuels such as coal and anthracite are heavy carbon dioxide emitters, messy to use and inefficient; 70 per cent of an open fire’s output goes up the chimney. Stoves, however, can provide efficiencies of more than 70 per cent while integral back boilers can power all or part of a conventional central heating system. Increasingly, multifuel and woodburning stoves are being sold as supplementary forms of heating, reducing the load on a gas or oil-fired system when a real fire is required. Wood and other forms of biomass, however, are a renewable energy source. Stoves and boilers which use wood pellets claim efficiencies and running costs equivalent to gas boilers, while the pellets allow automatic fuelling. Pellet suppliers, however, are still thin on the ground. Stoves and boilers are expensive; boilers are bulky and need ample storage space for pellets.
- Wood pellet burners are an investment in a low carbon future that will reap increasing benefits as fuel prices rise.
- The proposed Renewable Heat Incentives will make them very lucrative with returns of around 12per cent over 15 years.
- Pellet suppliers required.
- Pellet boilers don’t allow precise control of heating; installing a thermal buffer – a large hot water cylinder – between the boiler and the heating system is advisable to regulate the supply of heat.
Electricity is 100 per cent efficient and installation costs are low, largely because your home will need electrical power anyway. But it’s also the most expensive form of energy, and still generated largely by burning fossil fuels. As a result, electricity is mainly used either as a back-up – an immersion heater in the hot water cylinder – or a supplementary form of heating; a heated towel rail or background underfloor heating in a bathroom, kitchen or conservatory. Until recently off-peak storage heaters were the best known form of whole house electric heating. Electric boilers are available to power conventional radiator-based systems. They require minimal maintenance, don’t need a flue so can be sited anywhere and are very compact. Electricity’s biggest recent boost, however, has been the rise of heat pumps. Just as a refrigerator extracts heat from the items inside and disperses it externally, a heat pump draws heat from the ground or the external atmosphere and uses it to provide space heating and hot water. Is there enough heat available outside? Remarkably, there is. One metre down the soil temperature is between five and 12C degrees throughout the year. Tapping and concentrating this low-temperature warmth enables it to heat the small volume of water in a central heating boiler. The result is that each unit of electricity used to operate the system produces between 2.5 and four units of heat – a ratio known as the coefficient of performance (CoP). It’s not quite energy for free, but it brings electricity close to the cost of gas and oil-fired systems. The main drawback is the expense of the system, though there are grants to help out. Ground source heat pumps (GSHPs) are the most efficient. The most economic form of heat capture is via a ‘ground loop’ of pipe work laid in metre-deep trenches in the garden. The rule of thumb, however, is that the ground loop should take up 2.5 times the footprint of the house. Where space is limited a single, deep borehole can be used, but this is extremely expensive. Air source heat pumps are are a cheaper alternative. Thanks to the constantly varying temperature of the atmosphere, the CoP of an air source heat pump is typically around 2.5. A variation is the exhaust air heat pump. This extracts heat from air expelled from a mechanical whole house ventilation system. The house in question needs to be highly insulated with a high degree of air-tightness. Warm stale air is extracted via unobtrusive ducting and drawn through a heat exchanger in the attic. This warms incoming fresh air which is then distributed through another system of ducting.
- Heat pumps can provide heating at close to gas-fired prices.
- Cost can be reduced still further by incorporating other renewable energy sources such as solar thermal and photovoltaic panels.
- Most effective with a highly insulated house with high levels of airtightness and underfloor heating.
HOME HEATING DIRECTORY
Eastlands Court Business Centre, St Peters Road, Rugby, CV21 3QP
01788 555023 / email@example.com