The Government’s ambitious programme for new housing requires all new homes to meet strict zero-carbon standards by 2016 – and renewable technologies, such as heat pumps and solar thermal, are helping housebuilders achieve these targets. But the real challenge, some argue, is making the country’s existing 26 million ‘leaky’ homes energy-efficient. 

Improving energy-efficiency of British homes is potentially a huge source of income and employment and a UK Green Building Council (UKGBC) report calls it an ‘enormous business opportunity worth an estimated £3.5bn-£6.5bn a year.

We contacted Nu-Heat, a leading renewables and underfloor heating provider, to establish whether the retrofit market is a going concern, how the two technologies can be integrated into existing dwellings and what, if any, are the implications for today’s heating installers.

Market growth & government support

Nu-Heat’s solar thermal and heat pump orders have increased by around 30 per cent since December last year and although the majority tend to go into new build properties, the heating firm is experiencing a steady flow of enquires for the retrofit market, especially for air source heat pumps.

Adrian Troop, Nu-Heat’s Sales and Marketing Director, predicts this trend will gain momentum with Government grants making high-tech, energy-saving systems more affordable to a wider market. Homeowners, public sector bodies and businesses can apply for grants for approved solar thermal and heat pump products through the Government’s Low Carbon Buildings Programme.

Air source heat pumps only need space on the outside wall

But before recommending this route to customers it is worth pointing out that existing householders must conform to a number of energy saving measures before becoming eligible and applicants must also provide a Microgeneration Certificate Scheme (MCS) number. This can be obtained one of two ways – either through an MCS approved installer or an MCS affiliated company. Nu-Heat is part of the BRE’s Microgeneration scheme for solar thermal and heat pumps – putting the company in the strong position of being able to supply every customer with a grant application MCS number, contact with its accredited installer network and grant-approved, market leading products.

Taking the company-approved route assures homeowners and installers that both the product and design procedures will maximise system efficiencies – making sure the end-user is able to make the most of fuel savings will strengthen the reputation of these technologies and, ultimately, result in more enquires for the installer.

Design & project compatibility

If your customer’s home complies with the mandatory requirements, the next step is to check that the project is suitable for use with solar thermal and heat pump technology and companies like Nu-Heat, offering a design and supply solution, will take care of the complicated heat loss calculations to ensure the best solution for each particular project.

In order to discover the most appropriate product(s) to retrofit into the property, system designers will need information about the existing heating system: whether it has radiators or underfloor heating, the roof orientation (for solar), details about the cylinder/boiler configuration and the build type (to determine heat losses) –  this will allow designers to establish the dwelling’s heat load requirement.

Solar

With regards to retrofitting solar, Nu-Heat recommends either:

• replacing the existing cylinder with a thermal store
• using the present cylinder but installing a pre-heat cylinder,
  or
• replacing the current cylinder with a twin coil cylinder.

Based on recent solar retrofit sales, Nu-Heat states that installers are recommending on-roof systems to their customers as this method allows panels to be clipped and secured on the roof, whilst avoiding major alterations associated with the fitting of in-roof solar panels. 

Air source heat pumps

Air source heat pumps work best with underfloor heating but can run alongside radiator-based systems

Air source heat pumps are well placed for the retrofit market as they are probably one of the less invasive units of the heat pump family – the only space required is an outside wall.

Heat pumps, although more energy-efficient when combined with underfloor heating (due to the lower operating temperatures), can run alongside radiator based systems. An air source heat pump should cover the heating requirements of a well-insulated property in all but the most extreme conditions. When used in combination with an immersion heater both heating and hot water needs should be met, the immersion heater boosting water temperatures when necessary.

Installer implications

If integrating solar thermal hot water systems with a twin coil or pre-heat cylinder, heating engineers will need to be certified to carry out G3 Unvented Hot Water installations.

The industry is calling for professional installations and by virtue of this; Nu-Heat has formed a link with the NICEIC to offer a range of approved courses in solar thermal hot water, heat pumps and underfloor heating (as well as other associated topics such as G3 and Energy Efficiency). Nu-Heat is also offering one-day manufacturer ‘taster’ courses in these principles – please see Nu-Heat’s website for more details.  

For more information about solar, underfloor heating, heat pumps or renewables training, please call Nu-Heat on 0800 731 1976.

	Published: 20/05/09 (Previously published in HVP magazine)
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