The Code for Sustainable Homes supports Government plans to make all new homes zero carbon by 2016. Some organisations have deemed the objectives unrealistic; however, the Code does offer one major benefit to housebuilders as properties awarded six stars under the scheme will qualify for stamp duty exemption for being zero carbon. At present, stamp duty is charged at 1% on properties costing between £125,000 and £250,000, which means someone buying a zero carbon home for £200,000 would save themselves £2,000; a significant amount at the lower end of the market.

In fact, plans to create eco-towns across the UK moved a step closer last year with the first official zero-carbon home recognised at ‘The Big Build’ project during OFFSITE2007. The Housing Minister, Yvette Cooper, awarded a stamp duty exemption certificate to a prototype carbon neutral property – the most environmentally friendly home assessed under the scheme and the first to meet the highest standards laid out in the Government’s Code.

The construction methods championed by companies taking part in The Big Build included the integration of energy-saving technologies such as heat pumps and warm water underfloor heating – all of which achieve favourable energy ratings as such extras are awarded credits under the Code. In fact, the participants were so successful that the homes achieved a rating of between 4 and 6 (Levels 1 to 5 of the energy code represent improvements of 10-100% over the 2006 building regulations, with code 6 being zero carbon in terms of construction and operation).

With media speculation citing further deterioration of the housing market in 2008, stamp duty exemption may offer housebuilders an ideal marketing opportunity to capture the attention of cautious house purchasers, and integrating heat pumps and underfloor heating may be a way of achieving this.

Next generation in housebuilding – improve energy ratings with a heat pump

Ground source, air source and exhaust air heat pumps are designed to replace conventional gas or oil-fired boilers. They are at their most efficient when the water produced is between 35˚C and 45˚C, far lower than would be practical for a conventional radiator system typically needing water at 65˚C or higher, but ideal for warm water underfloor heating. Heat pumps are perfectly capable of producing water of a higher temperature but the Coefficient of Performance (CoP) suffers, falling to between 3 and 4 when delivering water at 50˚C, significantly compromising the economic and ecological benefits of the system. A CoP of 5 means that for every kilowatt of electricity put in, you get five kilowatts of energy out in the form of warm water. Under test conditions, the Nu-Heat ground source model has exceeded a CoP of 5 and Nu-Heat will always work in consultation with housebuilders to maximise the energy performance.

Although typically more expensive to integrate than conventional boiler configurations, heat pumps bring many benefits to a development:

• they have a positive impact on a building’s energy ratings,


• they will help housebuilders comply with government targets on energy and Co2  emissions,


• they enable housebuilders to market their homes to the energy conscious homebuyer,


• they may help achieve quicker sales cycles


• they help housebuilders obtain optimum selling prices for their homes

Combine heat pumps with UFH to further enhance energy ratings



The efficiency of any heat pump is improved when the temperature of the water flowing to the heating system is reduced. This makes warm water underfloor heating the obvious choice as most underfloor heating systems are designed to operate with a flow temperature of 35˚C to 45˚C.

In addition to this, a recent two-year study has confirmed that warm water underfloor heating really is more energy-efficient than radiators – something the industry has always maintained. In view of this, the British Research Establishment’s (BRE) revised version of the Standard Assessment Procedure (SAP), which will become effective during  2008, is expected to show UFH in a more favourable light; for the first time buildings fitted with UFH are likely to get better SAP ratings than those with radiators.

Installing underfloor heating need not be complicated, increase build costs or alter established construction methods. Whilst the rise in steel prices has contributed towards more expensive radiators, the rise in sales of underfloor heating has resulted in a more competitive market. The wide range of different design options now available guarantees straightforward integration into any floor construction.

Nu-Heat is well placed to lead house-builders through the design process of a combined underfloor heating and heat pump system as the company provides both energy-saving products. Purchasing the heat pump and heating system from one supplier means they will be totally compatible; there is just one point of contact for the housebuilder; and no conflicting advice.

Nu-Heat takes responsibility for producing time consuming calculations, for example those for SAP and Part E/Part L building regulation compliance. The company also operates a Housebuilder Partnership Programme, which offers builders complete project support from initial consultation with design partners through to a comprehensive purchaser/homeowner user guide.

If you would like a Project Manager to review an underfloor heating or heat pump project, or advise on how to achieve favourable energy ratings, please telephone Nu-Heat on 0800 731 1976 or email keyaccounts@nu-heat.co.uk