In December 2006, the government published a consultation paper Building a Greener Future detailing an ambitious target of zero carbon for all residential new builds by 2016.
This announcement came just months after the introduction of the 2006 Part L Building Regulations. Whilst these regulations demanded only relatively modest reductions in carbon emissions, they did focus attention on the need for superior insulation and air tightness specifications, and encourage the use of renewable technologies. Without doubt, the drive towards zero carbon homes will intensify interest in new and exciting technological advances and trigger their wider usage.
One such technology is ground source or air source heat pumps, designed to replace conventional gas or oil-fired boilers and provide exceptional efficiency.
Heat pumps are at their most efficient when the water they produce is between 350C and 450C, far lower than would be practical for a conventional radiator system typically needing water at 650C or higher, but ideal for warm water underfloor heating. Heat pumps are perfectly capable of producing water of a higher temperature but the efficiency rating or Coefficient of Performance (CoP) suffers, falling on average by 30% when delivering water at 500C, significantly compromising the economic and ecological benefits of the system. A CoP of five means that for every kilowatt of electricity put in, you get five kilowatts of energy out in the form of warm water.
 The most common method of extracting warmth from the ground is via collector pipes laid one metre below the surface in a series of horizontal trenches.
The amount of land needed is approximately double the floor area of the property to be heated (150m2 floor area requires approximately 300m2 land for the collector pipes), which could be a problem in densely populated urban areas. However, where land is at a premium, the collector tubes can be set into a vertical borehole; the earth gets warmer the deeper the borehole, so a correspondingly smaller amount of tube is required. This said, the geology of the British Isles is notoriously varied in its makeup, meaning quotations for drilling boreholes may also vary significantly as contractors allow for the worst-case scenario. Any uncertainty can be overcome by commissioning a geotechnical survey giving detailed information on exact ground conditions; the cost of the survey is likely to be offset by savings of up to 50% on the quotation price.
Where space is at even more of a premium, an air source heat pump may be the answer for heating and domestic hot water production. The unit itself works on a similar principle to the ground source heat pump but, as its name suggests, heat is extracted from passing air, requiring only an outside wall for installation and, therefore, greatly reducing cost. The only refrigerant present is contained within the unit meaning that it can be installed by a plumbing contractor rather than a refrigeration or air conditioning specialist. On average, the CoP is slightly less than for a ground source heat pump and units may require a supplementary source such as an immersion heater in severe weather conditions; a feature which is available on some units as standard.
As one of the UK's leading suppliers, Nu-Heat is well-established and also well placed to play its part in achieving government targets. Although UFH can be connected to all conventional boiler types, the lower water temperatures required make it the perfect partner for 'green' energy sources such as ground source, air source and exhaust air heat pumps. Nu-Heat has recognised the importance of this relationship and now supplies both technologies as well as a wide range of control options that can also contribute towards lower carbon emissions.
The very real practical benefits of underfloor heating are well documented:
more space, increased comfort, enhanced system control and lower running costs. UFH produces radiant, rather than convection heat, meaning warmth is concentrated in the lower part of the room where it is most effective, allowing thermostats to be turned down; its lower flow/return water temperatures mean less cycling of condensing boilers or more efficient operation of any heat pump. With the accepted life of a radiator recognised to be about 30 years and that of UFH heating tube at least 50 years with no ongoing redecoration costs, the lifetime costs of the heating system can be significantly reduced.
 The same can be said for heat pumps the government's Decent Homes Standard expects boilers to last for 15 years at the most and they should have annual safety checks by a Corgi registered heating engineer. Heat pumps require no servicing, just a simple annual check of the system pressure that also helps to keep costs down. They can provide energy for both heating and domestic hot water. Ground source heat pumps are also suitable for communal schemes where several homes are connected to a central unit.
Nu-Heat director, Adrian Troop says: "Whilst the rise in steel prices has contributed towards more expensive radiators, Nu-Heat's rising level of sales has resulted in more competitive pricing. The company¹s ability to offer a wide range of design options guarantees straightforward installation into any floor construction, and our experience of both underfloor heating and its integration with energy-efficient technologies ensures complete project support and valuable peace-of-mind for anyone considering them for the first time. Purchasing both heat pump and heating system from one supplier means the systems will be totally compatible; there is just one point of contact and no conflicting advice."
In order to achieve this level of expertise and service, Nu-Heat has invested heavily in product development and training with new products and floor constructions designed specifically to meet the requirements of Part L and to enable heat pumps to work at optimum efficiency. Expert guidance on suitable heat sources and Part L compliance strategies is provided and, where required, a SAP assessment service is also available. For flats or apartments that feature separating floors, the company also offers some unique Part E (acoustic) compliant solutions.
 Having established the most appropriate design, the focus must be on delivering a competitively priced system that can be installed quickly and without disruption to the build programme. All Nu-Heat designs meet the precise needs of each individual project with detailed installation information shown on layout drawings. Installation can be handled either by the self-builder, an installer recommended by Nu-Heat or the preferred plumbing contractor. The installation process is straightforward, requires no prior experience or specialist tools and is supported by award-winning documentation.
Finally, provision of a user guide will ensure that homeowners fully understand both the underfloor heating system and the heat pump and how to gain the most benefit from their energy efficient features.
For more information on how Nu-Heat can upgrade your heating system specification, or for further information on products, the design service or to receive a copy of the latest brochure, visit www.nu-heat.co.uk or call 0800 731 1976.
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