Category: Research

Today’s attitudes to low and zero carbon homes – views of occupiers, house builders and housing associations in the UK

This National House Building Foundation (NHBC) primary research report summarises the current thoughts, awareness and understanding towards issues such as climate change, the 2016 zero carbon definition, airtightness and renewable technologies.

Containing a detailed examination of responses from occupiers, house builders and housing associations, Today’s attitudes to low and zero carbon homes – views of occupiers, house builders and housing associations assesses the priorities of industry and the consumer when building or purchasing a new home.  It looks at views that could impact new homes of the future and sets the context for the research and presents the key findings, recommendations and current details of the definition of zero carbon homes.

Key findings

The study found that:

  • Home occupants were sceptical of the title zero carbon, but didn’t like new homes being described as eco or green either. There was one term that occupants did like: 70 percent thought the phrase ‘energy efficient’ would tempt them to look at a home. Occupants also had negative perceptions of the names of some eco-technologies, such as greywater recycling, but were more positive when a description was given.
  • More than half of occupants were slightly or strongly attracted to buying a home with solar thermal or photovoltaic panels, although interest was found to decline with age.
  • 53 of 54 occupiers whose homes had mechanical ventilation with heat recovery (MVHR) opened their windows on an occasional basis, with 57 percent keeping a window open at night. None said that they didn’t open the windows at all.
  • 87 percent of occupiers with MVHR kept the system running all or most of the time, but some turned it off in summer because they believed it used electricity unnecessarily.
  • 45 percent of housing associations said they have installed a back-up for a renewable technology in case of failure.
  • 23 percent of housing associations have decommissioned a technology because they have experienced problems. The report said that air source heat pumps and biomass boilers appear to have been most troublesome.
  • 39 percent of housing associations and 44 percent of housebuilders reported problems in sourcing reliable manufacturers. Only 31 percent overall could name a manufacturer with whom they have had a good experience.

Ways to improve attitudes

The report’s recommendations include:

  • The housebuilding industry should emphasis the lower running costs resulting from the energy efficiency of new homes through their marketing materials and sales staff.
  • Housebuilders need to adopt terminology that is user-friendly, engaging and easily understood.
  • Housebuilders must work to develop user friendly instructions and guides, training and intuitive control systems.
  • Valuers and mortgage lenders need to recognise that new homes save owners money in running costs, and factor this into valuations and lending decisions.
  • Occupiers should be encouraged to engage with renewable technologies and given more information about financial incentives.
  • Manufacturers need to develop products that work well in practice, with better technical support.
  • The government must confirm the remaining parts of the zero carbon definition to give industry confidence to engage with and respond to the challenge.

Further information

Article: Developers urged to improve occupants’ grasp of the benefits of green homes

 

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Breakthrough research for super-efficient solar cells at Cambridge University

New solar cells could increase the maximum efficiency of solar panels by over 25%, according to scientists from the University of Cambridge. Scientists from the Cavendish Laboratory, the University’s Department of Physics, have developed a novel type of solar cell which could harvest energy from the sun much more efficiently than traditional designs.

Solar panels work by absorbing energy from particles of light, called photons, which then generate electrons to create electricity.  Traditional solar cells are only capable of capturing part of the light from the sun and much of the energy of the absorbed light, particularly of the blue photons, is lost as heat.  This inability to extract the full energy of all of the different colours of light at once means that traditional solar cells are incapable of converting more than 34% of the available sunlight into electrical power.

The Cambridge team, led by Professor Neil Greenham and Professor Sir Richard  Friend, has developed a hybrid cell which absorbs red light and harnesses the extra energy of blue light to boost the electrical current. Typically, a solar cell generates a single electron for each photon captured.  However, by adding pentacene, an organic semiconductor, the solar cells can generate two electrons for every photon from the blue light spectrum.  This could enable the cells to capture 44% of the incoming solar energy.

Bruno Ehrler, the lead author on the paper, said:

“Organic and hybrid solar cells have an advantage over current silicon-based technology because they can be produced in large quantities at low cost by roll-to-roll printing. However, much of the cost of a solar power plant is in the land, labour, and installation hardware. As a result, even if organic solar panels are less expensive, we need to improve their efficiency to make them competitive. Otherwise, it’d be like buying a cheap painting, only to find out you need an expensive frame.”

Full article

 

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Managing grid-connected PV (photovoltaic) Power

Recent research from Strategic Business Insights (SBI) has highlighted that a long-term challenge to the widespread adoption of grid-connected PV (photovoltaic) power is managing the instability that can be introduced into the grid because of the intermittent and variable nature of PV power generation. Every type of solar installation loses power output rapidly when a cloud passes overhead. Cloud cover diminishes a major power source, disrupting power to potentially thousands of customers. Dramatic and immediate shifts in the nature of the power flowing throughout the grid can disrupt distribution across even larger areas because of how interconnected the system is—consider that the Northeastern Blackout of 2003 was traced back to instability caused by a power plant in Ohio.

SBI considers that large-scale grid-tied energy storage is the most direct solution to managing the fluctuations in power output from PV systems. Read more


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Improving the thermal performance of traditional windows

Based on research conducted by Dr Paul Baker of Glasgow Caledonian University (GCU) for Historic Scotland resulted in a report “Improving the thermal performance of traditional windows”. The report summarises the results of research on the thermal performance of traditional windows and methods of reducing heat loss carried out by the Centre for Research on Indoor Climate & Health, Glasgow Caledonian University (GCU) on behalf of Historic Scotland. Whilst most of the work was laboratory based using a sash and case window, some in situ measurements were carried out in a tenement in Edinburgh. Historic Scotland carried out a series of thermographic surveys to complement the thermal performance tests.

The report has concluded that:-

Laboratory measurements of the U-value of a traditional sash and casement window showed that there was no significant difference before and after draughtproofing of the window. The whole window U-value is 4.4 W/m2K. 72% of the heat loss through the window will be via the single glazing.

The airtightness of the window was improved considerably by draught proofing, reducing the air leakage by 86%. The window is tighter than the recommended 4000mm2 trickle vent for domestic new build.

All the options tested in the GCU Environmental Chamber reduce the heat loss through the glazing. Shutters are the most effective option of the traditional methods, reducing heat flow by 51%. By insulating the shutters heat loss can be reduced by 60%. Further improvement would be possible with a purpose designed set of shutters. Improved blind designs also have the potential to reduce heat loss.

High performance secondary glazing and replacement double glazed panes offer improved thermal performance throughout the day. Careful installation of the secondary glazing also results in improved air-tightness.

All the options offer improved thermal comfort due to higher surfacetemperatures compared with single glazing alone.

The in situ U-value measurements confirm in practice the performance oftraditional shutters and show the potential benefits of low emissivity glazing in a secondary glazing system.

Effect of the options on U-value
Effect of the options on reduction in heat loss through the glazing

Notes:

U‐value (or thermal transmittance co‐efficient) is a measure of how much heat will pass through one square metre of a structure when the temperature on either side of the structure differs by 1 degree Celsius. The lower the U‐value, the better is the thermal performance of a structure. The U‐value is expressed in W/m2K.

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Energy Heritage: a guide to improving energy efficiency in traditional and historic homes

This guide provides options for improving the energy efficiency in traditional and historic homes. It addresses the following questions:-

  • What issues affect energy efficiency improvements in historic buildings?
  • What opportunities exist to enhance historic homes?
  • What lessons can be learned from other experiences?

It includes a case study of a project carried out in an 1820s tenement building (a traditional Scottish dwelling type with a common stair) in Edinburgh, Scotland.

 

 

Further details

Download the Full Report: – Energy Heritage: a guide to improving energy efficiency in traditional and historic homes

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