Selfbuild 123 - How to Self Build a House
Selfbuild Central Heating
Central heating fuel
If you plan to selfbuild your new home on an infill site or on the outskirts of a town then connecting to the mains gas supply should not be a problem. However, the reason why so many people self-build is to get away from it all, and where this is the case mains gas is not usually available. I was lucky with my selfbuild, mains gas was available, but it cost me £1400 and I had to dig a 200m trench to the main road.
In fact, an estimated 70 per cent of self-builders have to find an alternative fuel to heat their home. The other options are Liquefied Petroleum Gas (LPG or 'bottled gas'), oil and electricity. Solid fuel can also be used, although the majority of selfbuilders choose this for a supplementary form of heating - eg. Wood burning stoves.
Oil is the cheapest, followed by mains gas, LPG and then electricity. Running costs will also be determined by the efficiency of your heating system. At the centre of this system is a boiler or cooker which burns the fuel to provide both space heating and hot water.
Central Heating Boilers
There are three main types of boiler: conventional, combination and condensing. A conventional boiler is a good choice for large families who need plenty of hot water and are typically between 75-88 per cent efficient. If you can't wait for water to be heated in the conventional way, then combination boilers heat water direct from the mains, eliminating the need for cylinder in the airing cupboard and tank in the loft. As no energy is wasted in keeping stored water heated energy efficiency can be as high as 90 per cent. At the top end of the market, both in terms of price and efficiency is the condensing boiler. These use an extra heat exchanger to recover and recycle more of the heat that would be wasted by a conventional boiler an typically give an energy efficiency output of between 90-95 per cent. A further development in this market is the 'condensing-combi' boiler, which combines the efficiency of the condensing boiler with the performance of the combination boiler.
All these boilers can now be bought to run on one of a range of fuels and can be used to heat water for radiators and underfloor heating. If you want to go for underfloor heating, then a condensing boiler will prove the most energy efficient. This is because an underfloor heating system uses warm (as oppose to hot) water and a condensing boiler relies on a low water temperature return so that it can condense.
A boiler is only as efficient as its controls. An energy management system (EMS) can improve the efficiency of your heating system even further by monitoring the temperature of the water within the boiler and preventing the boiler's burner from firing if there is no need to do so.
If you are planning to selfbuild a traditional country-style house a central heating cooker is worth considering as an alternative to a boiler. The top of the range can provide both domestic hot water and run your central heating system.
Central Heating Radiators
A conventional central heating system will of course use radiators. These now come in a variety of shapes, sizes, styles and colours so you can choose the right ones for your home - whether you are building a contemporary or period style of house.
If you want to keep your walls free from radiators, then underfloor heating is now very popular with selfbuilders. Similarly to a radiator, an underfloor heating system uses water as a medium, but instead of the water passing through a wall-hung apparatus, it is circulated through special pipes installed into the fabric of the floor. Most of the heat output is in the form of radiant heat which transfers from the system straight to you, creating a noticeably more comfortable atmosphere. As radiant heat eliminates the wasteful build-up of heat under the ceiling, underfloor heating is more energy efficient, proving especially economical in homes with high ceilings. The decision to have underfloor heating should be made early on in your project, as you will need to plan it in conjunction with the floor construction. A concrete screed covering provides a higher heat output, although the system can also be installed with suspended timber floor construction.
Fires and stoves
The decision to have a fireplace for an open fire or stove should be made at the design stage, as you will need to plan for a load-bearing floor and a class one chimney. Few selfbuilders can resist the hypnotic appeal of a real open fire, although these are not very efficient with around 75 per cent of the heat going straight up the chimney. You can increase the efficiency of a real fire by either installing a back boiler or to contain it in a firebox - a stove. A stove can enjoy 80 per cent efficiency and more.
The majority of selfbuilders choose solid fuel fires and stoves, although a flame-effect 'fire' or stove, running from gas, oil or electricity is obviously a cleaner option. If you go for a flame-effect electric stove then you will not need a flue or chimney.
Stoves and fires come in a variety of shapes, sizes and styles so you will be able to choose the one that best suits the interiors of your new home. Remember, by law, a CORGI registered fitter should fit all gas appliances. Contact the Council for Registered Gas Installers (CORGI) (Tel. 01256 372300) for details. If you are planning to use solid fuel, contact the Solid Fuel Association (Tel. 0800 600 000) for information and advice.
Whatever heating system you want, it is worth spending time with your architect / builder and potential suppliers discussing your precise heating needs so you get the right system for your new home.
By investing in the energy efficiency of your home, you will not only be doing your bit for the environment, but also making savings on your fuel bills. This does not mean sacrificing on your comfort, with the right advice and proper planning you can have a house that is just as warm and as pleasant as your neighbours - just with cheaper running costs!
Energy savings are achieved by a combination of more efficient heating and ventilation systems, better insulation, draught-proofing and high-performance windows.
Your choice of insulation materials (for the walls, roof and floor) is crucial and you should always take professional advice, especially on how these should be installed. Your heating system should be designed to complement the high levels of insulation in your home. There is no point in over specifying a boiler for the sake of it! A completely sealed and insulated system would result in very humid and unhealthy conditions inside the building, so proper ventilation will also be required. Again, take professional advice.
If you can take energy from renewable energy sources, such as from the sun, then even better. As well as fitting solar panels, incorporate passive solar features into the design and layout of your new home, giving careful thought to the positioning of windows ensuring that they will gain more heat from the winter sun that they will lose.