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More and more homes are being built outside major conurbations. These range from self-build homes – which topped 11% of all housing starts just a few years ago – to new estates aimed to meet government demands for more new housing. Add to this the current stock of rural and remote dwellings looking to upgrade and there is a massive market of over two million homes – none of which are served by mains gas.

Meeting demands
The householder of today demands the comfort of easily controlled and economical central heating. In the past, the alternatives have usually been bunkered fuels, the most traditional being solid fuel. This is fast losing popularity due to inconvenience and poor temperature control.

The price of oil seems to have a bumpy ride with every Middle East crisis and demands space for a storage tank with ancillary equipment that raises the installation costs. Also expensive to install, liquid petroleum gas (lpg) – often hailed as the alternative to mains gas – has proved to be the most expensive fuel for central heating.

Factor in the extra costs of fuel storage, plus access for deliveries and someone to oversee the ordering and suddenly things don't look so bright.

On out of town housing estates not served by mains gas, gardens are usually too small for fuel storage. In multi-storey accommodation, mains gas may not be a viable option, even if it is available. Consider also the problems of tenanted properties, where landlords have to pay a qualified engineer to annually service all gas appliances, and it becomes apparent that there is a real need in the market for a cost-effective, efficient alternative.

The electrical alternative
There is a logical alternative – electricity. Electrical heating has had something of a chequered history, with a Hobson's choice between poor control and high running costs.

Plug-in space heaters may offer heat where and when it is needed, but they are expensive to run. They operate on the highest cost tariff and, in the main, they lack power modulation. In other words, they are either fully on or off, which is like driving a car everywhere on fully throttle.

The main alternative has been night storage heating. While some tariffs are becoming more flexible, there is still a problem of trying to outguess the British climate 24 hours ahead.

Up to now, electrical heating has never enjoyed the same popularity as gas or even oil in the eyes of the British public, so the electrical contractor has never really shared in this lucrative market.

The introduction of a cost-effective, efficient and easily installed electric central heating boiler could change this.

One such product, the Amptec electric flow boiler does exactly the same job as a gas or oil-fired boiler ie heating primary water that is pumped round a conventional wet heating circuit and indirect domestic hot water cylinder, either tank-fed (vented) or on a mains pressure (unvented) water supply system.

A very important difference for the householder and the installer is that an electric central heating boiler creates no combustion gases, so the system does not need a flue. This reduces installation costs and opens up new options for siting the boiler which, unlike gas or oil, does not need to be near an outside wall or existing chimney.

This flexibility is further enhanced by the linear design of the Amptec boiler, which gains maximum heat transfer by being one metre-long but only nine centimetres square. This compact size allows the boiler to be fitted anywhere convenient to the power and water supplies.

With no flue requirement, this provides a realistic wet central heating solution where space is limited, making it ideal for flats above ground floor level or in listed buildings where permission for exterior alterations may be required. Installation is straightforward, with all electrical connections and servicing accessible from the front.

The Amptec option
Amptec C model electric flow boilers are suitable for conventional wet radiator systems with operating temperatures between 65-80°C. They come in a range of outputs – from 3 kW suitable for a small flat; 4, 6 and 9 kW up to 12 kW to provide the heating and hot water for a family home. There is also an 11 kW model designed to serve existing properties with older consumer units.

In dwellings with an electric shower, relay assemblies are available to prevent the boiler and shower operating together and overloading the electrical supply.

A new option with the same power outputs is the U range designed expressly for underfloor heating systems. With an operating temperature adjustable between 30°C and 60°C, these simplify the heating pipework, cutting out the need for extra thermostatic and flow control valves by providing the correct water temperature at source. These boilers can also be used to solve the programming and control problems that may occur on split systems where living rooms use underfloor heating but carpeted bedrooms retain radiators.

The next major point of concern is running cost. With no flue heat losses, an Amptec boiler returns 99·8% efficiency. Bearing in mind that Sedbuk (seasonal efficiency of domestic boilers in th UK) A-rated gas condensing boilers just top 90% efficiency, the Amptec boiler goes a long way to reducing the fuel cost differential.

Add the on-board energy management system that provides fully modulating operation and you have a conventional central heating system with full 24-hour programme control. In many cases it is more cost-effective to run than night storage heating and much more convenient and user-friendly.

An added bonus is a recent agreement with Scottish and Southern Power that includes Amptec boilers in their E10 tariff – allowing up to three low-cost periods over 24 hours. This major supplier group covers around half the UK, further reducing the cost of electric central heating for many consumers.

Proving a point
A point of concern for installers and consumers is product reliability. Can this new system match up to more traditional options? The answer seems to be an unequivocal yes.

The Amptec boiler utilises soft-start and soft modulation, zero volt, Triac, solid-state switching, offering longer life and better surge capability than mechanical switches or relays. In addition, solid-state, twin thermistors check correct water supply, flow direction and temperature levels, plus self-check diagnostics between the two thermistors, with any faults or anomalies activating the on-board alarm and shutting the system down in safe mode.

Naturally, these fail-safes are only as good as the overall engineering. Every Amptec boiler is tested at works before dispatch and their product reliability record stands at over 99%.

For electrical engineers, the introduction of the electric flow boiler adds a new and profitable dimension to domestic and light commercial installations. Electrical heating has come of age, offering the customer the expected luxury of wet central heating powered by a door-to-door mains service in most areas where mains gas is either unavailable or inappropriate, at an economical cost.