Keep domestic heating costs under control

The cost of installing new domestic heating controls can be easily offset by savings in energy bills. A further incentive comes in the form of the improved level of comfort that is achieved by delivering heating and hot water at the times they are required by the household.

Existing controls

Vaillant commercial director (UK and Ireland) Dave Lacey (pictured) says an installer’s first step should be to look at the controls already in place to ensure those fitted are set and operated correctly, and to fit appropriate controls where necessary.

“Controls should allow the user to set the times and temperatures required for the heating within the property, preventing unnecessary running of the heating system - for example, when a property is empty during the day,” he says.

Without the control of a room thermostat, some boilers may cycle continuously, wasting fuel and increasing costs, as well as wear and tear.

A programmable room thermostat takes the element of control a stage further by allowing different temperatures to be set for different times of the day, providing a further saving of 5 to 10 per cent, says Mr Lacey.

More sophisticated control features, such as weather compensation, can also be added. “Wise installers are undergoing specific training in aspects of system design, including which control options will benefit the end-user. With the right controls, correctly used, a comfortable indoor environment can be achieved without having to worry about high fuel bills,” Mr Lacey concludes.

Expert advice

Installers providing helpful advice to offset hikes in energy costs stand to gain more business, says Chalmor managing director Steven Henry. “The latest Ofgem figures say the average home energy cost will rise to £1,345 a year. Heating professionals can offer expert advice to homeowners on how they can help to mitigate their energy costs.

“About 95 per cent of the UK housing stock consists of traditional homes rather than new build, so the focus needs to be on improving these buildings.”

The latest electronic technology enables homeowners to control energy use while the system delivers improved comfort, he says. Users are nowadays more aware of this, and better controls will also help them deal with the vagaries of the British climate.

“By integrating boiler and space-heating control, savings on fuel bills as well as on CO2 emissions can be made,” says Mr Henry.

Correct commissioning

In addition to ensuring correct thermal insulation of a building, it is also vitally important for a heat pump to be commissioned correctly, according to Daikin heating and renewables product manager Nancy Jonsson.

As part of this process, it is important to set up the heat pump’s user controls correctly. The temperature of the water leaving the heat pump should be as low as possible, in order to maximise the device’s coefficient of performance while still ensuring comfortable conditions will be achieved in the building.

The required flow temperature will depend on the heat emitters installed and the heat loss of the building. “A good heat pump will always have a weather compensator and the heat pump should be set to this whenever possible, because heat pumps operating on weather compensation instead of a fixed temperature will be more efficient,” says Ms Jonsson.

“If economy electricity tariffs are available, the heat pump should be timed to come on during these periods, with restricted use at other times where possible.”

Consideration should be given to hot water requirements when space heating demand is likely to be low - in the early hours of the morning, for example, to ensure that space heating is available when required.

Where there is a back-up heating source, this should be programmed to come on only when absolutely necessary.

The operation of the heat pump should be explained to the end-user. Installers may also consider restricting access to a few key functions to prevent changes being made that could result in inefficient operation.

Call-out considerations

Heatline commercial director Mark Derbyshire outlines a common scenario: “The weather turns colder, homeowners switch their heating on for the first time since spring and find that it isn’t working.”

When attending call-outs to fix boilers, installers can also consider updating radiators, which may be old, incorrectly sized or poorly installed.

When discussing a system upgrade, it is vital to look at the bigger picture, considering the entire heating system to ensure that the benefits expected and financial return can be delivered.

The tasks carried out should include a full check of the existing radiators, including age, condition, surface temperature, whether the system is balanced correctly, or if thermostatic valves have been fitted.

Energy-saving measures carried out since the last boiler replacement should be considered, as this will affect heat loss, and radiators may be incorrectly sized.

“Ask if the homeowner is planning any extensions or refurbishments. Not only could this affect the size of the boiler but also the size of the radiators,” says Mr Derbyshire.

Further tasks to complete include a heat loss calculation and system flush, along with recommending a system cleanser and corrosion and scale inhibitor.

Efficiency assessment

The subject of the efficiency of space and water heating appliances is raised by Zenex Technologies chairman Tony Billett, who states that the government’s drive to improve the insulation and air-tightness of buildings is meeting with some success.

“However, as far as the homeowner or occupant is concerned, all this good work is being undone by rising energy prices, which means that they aren’t seeing any real saving,” he says.

The parallel push towards installation of more efficient appliances is no less important, because here we are talking about actual running costs. “But what if the energy efficiency that is being delivered by appliances is less than promised?” he asks.

The reason some boilers and water heaters are being assessed as inefficient lies in the way the previous government laid down the rules for assessment of the efficiency of condensing boilers.

The Boiler Efficiency Directive used to assess and rate boilers only applies to space heating-using radiators and does not consider domestic hot water, which is becoming the main use for domestic boilers as buildings require less energy to heat.

In some cases, boilers may only be delivering 30 per cent efficiency, far below the performance homeowners were led to expect, says Mr Billett.

Research by Defra’s Climate, Energy and Households Team has found that water heating efficiency is considerably lower than that of space heating, and separate findings from the Energy Saving Trust and others confirm this.

“If we are truly to provide energy efficiency, we need now to look beyond the building envelope and look once again at the way in which we assess appliances,” he concludes.

Efficiency assessment

Smith’s Environmental Products sales and marketing director Jim Bennett says using fan convectors alongside renewable technology can keep heating costs and carbon emissions to a minimum.

The former are extremely controllable and can be switched on and off independently or automatically with any heating system. External and integral thermostats provide homeowners with greater control, while reducing the quantity of latent heat that other appliances produce.

Fan convectors can be used in both existing and newly built properties, he says. They are low surface temperature appliances with low water content, so can heat up (and cool down) quickly. Running at low water temperatures allows them to be used with carbon-cutting technologies.

“The technical facts speak for themselves,” says Mr Bennett. “The published coefficient of performance of a heat pump is given at an exit water temperature of 35 deg C. Indeed, industry standard testing (EN14511) for air-source heat pumps is carried out at an air temperature of 7 deg C and a water temperature of 35 deg C.”

With fan convectors, the heat pump will always be running at close to optimum efficiency, he continues, and recent developments have seen fan convectors close the gap on radiators even further. These new products are low in cost and simple to install, with the added benefits of being smaller and lighter than panel radiators of equivalent output.

For instance, the equivalent-output radiator could be as much as 2.2 m long and 55 kg in weight, and would take three men to lift, whereas new fan convector products can be lifted single-handedly.

“When it comes to domestic heating systems, end-users and installers need to be more aware of the energy efficiency credentials of fan convectors as a viable alternative to radiators.

“After all, if a domestic heating system is to be deemed truly energy-efficient, the emitter needs to be equally as ‘green’ as its heat source,” Mr Bennett concludes.