Weekly Email News – the future of the building industry


Warm tie

Ancon’s range of low thermal conductivity wall ties minimise heat loss through thermal bridging, improving the energy efficiency of a masonry cavity wall.

The use of these ties can reduce insulation depth and wall footprint.

In addition to a number of stainless steel wire wall ties, the range includes the Ancon TeploTie which is manufactured from pultruded basalt fibres set in resin. This BBA-approved product is available exclusively from Ancon. It has a thermal conductivity of just 0.7W/mK, making it the most thermally efficient wall tie on the market, the company claimed.

It has already been used on the first certified Passivhaus to be built with traditional masonry cavity walls and the first retrofit to be built to Level 6 (Zero Carbon) of the Code for Sustainable Homes.

Ancon now has a BBA-approved, low conductivity wall tie for cavities from 50mm to 300mm.


Tackling VOCs

Fermacell is a modern building which can help improve the overall BREEAM rating of a building.

A new product called Greenline was launched by Fermacell at Ecobuild and effectively tackles VOCs. The main difference between Greenline and standard Fermacell high performance dry lining boards is the addition of a natural additive that absorbs VOCs leaching out of compounds as gases.

Fermacell is a multi-purpose board providing high acoustic, fire, moisture, impact resistance and excellent racking strength properties.


On cue for recycling

Snooker legend Steve Davis gained another winning frame when he called in on Network Veka fabricator Glazerite Windows to find out about recycled PVC-U windows.

The six-times World Champion had set out to learn hands-on every step of the recycling process for a consumer DVD and dropped in on Glazerite’s North West division in Bolton to help make a window from Veka’s Infinity recycled profile.

Steve was filmed through every stage of fabricating the frame before declaring it “a new kind of window for a new generation of homeowner”.

Recently, Glazerite made the first ever recycled window to go into a UK private house. In the final DVD, produced by Network Veka, Steve will be seen helping to install that window before following the journey of one old frame all the way through Veka Recycling in Kent to Veka in Burnley, where the Infinity system was conceived and is made, then on to Glazerite.

Infinity uses a co-extrusion process where pure recycled PVC-U is locked inside a thin outer wall of virgin polymer, making it nearly 80% recycled material in total and with only a third the carbon footprint of a conventional window.

The Infinity system is fully compatible with the existing Matrix 70mm range and available on a standard five-day lead time. Glazerite is confident the profile will appeal to environmentally conscious homeowners and commercial specifiers alike – both expanding markets – as well as demonstrating considerable corporate social responsibility and commitment to the environment.


Underpinning success

Low-carbon energy company, LowC Communities, has underpinned its recent progress with the appointment of Jane Mellor to the role of finance director.

Based at its headquarters in Stamford, the company specialises in the design, construction and operation of renewable energy infrastructure for public and private-sector buildings. Launched in 2007, LowC has become known in the energy sector.

Richard Griffin, managing director, said: “We are really pleased to welcome Jane into her new role at LowC. Her qualifications and experience will be vitally important as our company continues to implement its strategy for growth.

“With irrefutable evidence of climate change hitting the headlines and our Government having signed up to internationally binding targets to reduce global carbon emissions, LowC’s offering is becoming ever-more relevant. Jane will be a key part of the team and we are all looking forward to working with her.”

Jane had previously run her own accountancy practice, after a 19-year stint with the American-owned, Liant Software. Having worked her way up to the dual role of managing and finance director, Jane was responsible for a turnover of £3m and a team of 13 staff covering Europe, Middle East, Africa and parts of Asia.


Super efficient doors

Solarlux has launched its most efficient glass door to the UK market.

Combining four core elements that enable the door to achieve a U-value of 0.80Wm2K, the new SL97 wood/aluminium folding glass door is specially designed with the demands of energy saving in mind.

By using wood internally and a combination of insulating material and protective aluminium externally as well as triple glazing, the SL 97 has been able to combine the advantages of four materials.

Inside, the wood panels create a natural warm atmosphere and, on the outside, the fully insulated rear-ventilated aluminium facing sheets guarantee permanent protection from the elements with only minimal maintenance. The company envisages applications both in luxurious private homes and multi-storey high-quality rented and owner-occupied flats.


Sustainable alternative

Timbmet, one of Europe's leading timber distributors, and the UK's exclusive supplier of Red Grandis, a Pure Forest Stewardship Council (FSC) red hardwood, is to offer a legal and sustainable alternative to Sapele or Meranti timber.

The introduction of Red Grandis demonstrates how a new plantation-grown species with Pure FSC certification can be brought to the market with customer benefits in terms of sustainability, natural durability, ease of use and continuity of supply – particularly important given ever increasing global demands on timber as a natural resource.

A high-grade clear timber delivering consistency of colour, appearance, grain and workability, Red Grandis – or Eucalyptus grandis, to give it its generic name – is most often used in the production of internal mouldings, including skirting, architrave and thresholds, furniture, cabinets and exterior cladding profiles, as well as within the window and door frame industry.

Red Grandis has undergone independent third-party testing by Trada Technology and Building Research Establishment, achieving great results for natural durability and resistance to fungi – key for long-term performance – as well as Class D35 for strength and stiffness, and Class C35 for density to prove its suitability for joinery and structural use.

Under the plantation growing process, intensive pruning is carried out to provide a knot-free, clear, uniform timber with sapling thinning to enable the trees to reach significant diameters. It is easy to machine and shape, and because all lengths are identical, there is less waste and reduced production time, as well as a much better finish overall.


Warm roof

In a bid to provide a more cost effective and thermally efficient alternative to solid roofs, and which escapes local authority ‘red tape’, Ultraframe has developed Utopia, a new style of double layered conservatory roof technology which has been designed to dramatically improve a roof’s U-value and extend the use of a conservatory to 365 days a year.

Using fully thermally broken integrated support extrusions, Ultraframe’s Utopia eco roof features two layers of polycarbonate, 35mm Heat Guard Opal externally and 32mm Opal internally, along with an internal chambered ‘T’ cladding and a chambered ridge undercladding.

The centre pane U-value of the two sheets of polycarbonate is just 0.6, producing a conservatory roof that requires only 788kWh of heating energy a year, 1300kWh less than the average and saving the average household at least £200 on heating their conservatory.

Andrew Thomson, technical director at Ultraframe, said: “It’s common knowledge that conservatories can often overheat in summer and become too cold in winter, making them uncomfortable to sit in. The reason for this is that in summer, most conservatories simply don’t reflect the heat and end up overheating, while in winter, the roof’s low insulation value can become a problem.

“Traditionally, homeowners have looked to combat this and achieve lower U-values by retrofitting a solid roof and turning the conservatory into an extension, which can often mean doubling the cost and obtaining Building Regulation approval.

“As the industry leader in conservatory roofs, we knew we had to develop a new technology which would improve the U-value of a conservatory roof and allow consumers to enjoy their conservatory 365 days a year, come rain or shine.”

Until now, conservatory roofs have been designed with a single layer of polycarbonate or a double glazed sealed unit, resulting in an average U-value between 1.1 and 1.7. By adding another layer of polycarbonate, Ultraframe’s next generation roof solution can achieve a centre pane U-value of 0.6 and save homeowners hundreds of pounds on their heating and energy bills, as well as increasing winter usage of the area.

Andrew continued: “By installing a Utopia system as opposed to a solid roof extension, consumers are able to enjoy the benefits of light and space that come with a conservatory.”

Manufactured with heatguard externally and opal polycarbonate internally, sunlight is better reflected off the Utopia roof, extending the number of hours homeowners can use their conservatories in the summer months. In addition, the double layer polycarbonate also acts as a great barrier to noise transmission, reducing disturbance from outside sources.


New triple glazing

Network Veka fabricator, Blair Neill, has launched a triple glazed PVCU window with a U-value of just 0.8Wm2/K

“We want to give customers something better than A rated windows,” said Peter Blair, MD of Blair Neill. “Rising heating costs are a continuing worry for homeowners and they are looking for new ways to keep bills down. So we’re launching a window that meets the U-value of Passivhaus standards for windows giving installers a real advantage over competitors.

“The frame is insulated with a foam thermal-core and combined with the triple glazing gives a window with just 0.8 U-value and the good looks of a PVCU frame.

“The benefits of the new window are easy to show homeowners with a brochure dedicated to EnviroHome.

“Adding new products and marketing support through EnviroHome is just part of a substantial investment programme for our customers. We know it’s a tough market that’s why we’ve put everything possible into making it easier for customers to sell more. These additions ensure that Blair Neill continues to lead the market for professional installers.”

‘Advanced’ window

Pioneer Trading has launched the Signature High Performance Window.

The company’s managing director Danny Williams claims it is ‘the most advanced window available in the market’.

Pioneers has developed the sash to accept both triple and double glazed units. Danny said: “When I designed this sash it was with the future firmly in mind. It has been clear for some time that the present Window Energy Ratings maximum can be relatively easily exceeded and future advances in performance would require triple glazing. We took that into consideration and we have a window that can accept triple glazed units without modification, in addition to relatively low specification glazing units that will still achieve an A rating. Our claim will stand the test: this is the most advanced frame you can buy today.”

The sash incorporates a sophisticated cell structure that allows the production of a C Rated frame with a standard IGU, and an A Rating with the simple addition of a warm edge spacer – no argon required. The preclusion of expensive low iron glass for even the highest WER alleviates the problem with condensation associated with this type of glass.

Use of a fully specified IGU promotes performance of the Signature Sash to an A+30 rating.

The Signature High Performance Window offers a slimmer section providing a significantly greater glass area, important when replacing smaller windows and frames such as bays. Weight and cost is reduced as steel reinforcement is minimised and the super-stiff profile has extra screw porting for significantly better location of hardware; this significantly improves the security of the sash.

The rigidity allows a wider span for the sash, from the assumed maximum for PVCU of 600mm, to 700mm. Fitting is also easier with the bead ‘especially slippery’ to ensure it drops into place securely with minimal effort and fuss.

Heating evolution

A new highly efficient woodburning stove that incorporates a boiler to generate hot water for central heating and can be connected directly to a sealed heating system as well as plumbed conventionally on an open system has been launched by Broseley Fires.

Like all stoves in the company's eVolution range, the new eVolution 8 combines eco friendly features with a contemporary design and the latest in stove technology, including the Safety Cold Water System (SCWS) which was pioneered by Broseley Fires.

SCWS enables Broseley’s solid fuel boilers to be fitted onto new or existing sealed central heating systems without the need for additional pipework and controls to vent the boiler. The eVolution 8 system can easily link up with other boilers or heat sources such as solar panels or ground source heat pumps through connection via a thermal store or low loss header.

The eVolution 8 boiler stove was developed by Broseley to meet the growing demand in Europe and the UK for highly insulated, air-sealed housing and sealed heating systems. The system means that, for the first time, a wood-burning boiler can be seamlessly integrated into an existing sealed heating system, including combi boilers, with no additional expansion tanks or unsightly pipework.

The eVolution 8 is a free standing stove which is designed to maximise convection heat output from all working surfaces. The huge 400mm x 300mm glass panel has a door designed for a crisp, quality closure and is kept clear with a pre-heated air wash offering high visibility of the flames. The slimline design is finished in grey painted steel and has a nominal heat output of 11kw, 8kw to water and 3kw to room, and is one of the most efficient in the industry operating at 83% efficiency.


Seasonally efficient chiller

Daikin Europe has introduced EWAD~CZ air-cooled inverter chiller range with the highest ESEER (European Seasonal Energy Efficiency Ratio) in the market – up to 6 (with optional fan speed regulation) making it a highly cost-effective solution for use in comfort cooling and other applications where a high quality chiller in terms of performance and reliability is needed. Highest partial load efficiency: ESEER up to 6.

The use of inverter driven screw compressors in the EWAD~CZ range allows units to achieve the highest partial load efficiency levels in their class, making them ideal for systems with variable load requirements such as comfort applications. The high partial load efficiency of these solutions allows substantially reduced CO2 emissions and decreased annual operating costs with attendant reductions in payback times.

The use of inverter technology also contributes to quieter sound levels and precise chiller water temperatures, as well as lower starting current requirements, optimum power factors (always above 0.95), a reduction of water tanks for the hydraulic system and increased reliability due to fewer compressor start-ups and shut-downs.

Inverter control is complemented by a host of other advanced features such as a patented single screw compressor, and ultra efficient fans with a patented blade profile for quiet operation. Furthermore, the new Microtech III controller allows easy control of performance parameters, and a wide range of system integration solutions are supported including LonWorks and BACnet.


Cladding includes PV modules

New from Schueco UK is SCC 60 with ProSol TF, a cladding system for the side of buildings and other structures, purpose-designed for use with ProSol TF thin-film PV modules.

The resulting ventilated facade is multi-functional and can provide weather protection, excellent insulation and sustainable energy production all in one package.

In addition to the cladding system and PV modules, Schueco also supplies all the additional components, known as the BOS (Balance of System), such as wiring, connectors, inverters etc that are needed to achieve an optimum system configuration and low system losses.

ProSol TF modules use amorphous thin-film technology, the key advantages of which are a more effective use of the light spectrum and a low level of dependence on temperature compared to crystalline products. Energy is therefore produced even in cloudy or twilight conditions enabling the system to achieve the highest possible output per installed Kwp.

Modules can be up to 2.6m wide x 2.2m high, but the use of Schueco’s fixed-size module measuring 1.3m wide x 1.1m high offers substantial economic benefits.

Many types of buildings in both the private and public sectors can benefit from Schueco SCC 60 with ProSol TF including multi-storey flats and offices, warehouses, industrial buildings, hospitals and colleges. Moreover, since it is ideal for retro-fitting, the system can be used to rejuvenate old buildings by improving their energy balance, cutting CO2 emissions and equipping them with a new income stream.


Launch sealed

Tremco illbruck has launched a new sealant which has a focus on environmental as well as technical issues.

European president Reiner Eisenhut said: “In the area of looking at insulation around window openings, we know we can save a lot of energy.”

i3 brings together three products to create a vapour permeable sealing system also capable of achieving the air tightness necessary for low carbon living.

An appropriate thickness of Compriband 600 tape takes up the gap between window frame and reveal, before illbruck FM230 Window Foam+ is injected around the inner side of the joint. Illbruck Duo Flexible Membrane then provides an air tight seal between the inner side of the frame and the wall’s air barrier line before final finishes are applied inside and out.

Tremco illbruck’s UK director and general manager Richard Hill said: “We are a building solutions provider: sealing, waterproofing and weather-proofing structures in order to improve the performance of properties. It is in the areas of windows, walls, roofs and floors that our products can really make a difference.

“Our i3 system is ideally suited to use in Passivhaus and Code for Sustainable Homes constructions. They are equally applicable to refurbishment work as well as new build projects.”


‘Revolutionary’ green technology

Energy company BSolar has become one of the first companies to install a new ‘revolutionary’ solar panel in the UK.

The company based in Halsall, Lancashire, recently completed a job in Lancashire, installing Sanyo HIT panels, a new super efficient solar panel which can generate up to 50% more energy than a normal panel.

The Sanyo HIT panels combine two solar technologies and Peter Bladen, director at BSolar, expects these new panels to be a big success with homeowners across the UK.

He said: “These new panels are a breakthrough in technology, they are very energy efficient so fewer panels are needed, which is useful for people who have a limited amount of roof space available. They also perform better under less than ideal circumstances, so are incredibly super-efficient.

“We have seen a huge increase in people across the North West wanting to have solar panels installed which has been boosted by the government’s Clean Cash Back scheme and we are expecting this growth to continue with the introduction of the Sanyo HIT panels.”

The government’s scheme rewards homeowners who generate electricity from renewable sources by paying them 43.3p per unit that is generated from the panels.

Peter said: “It pays to be green. An average solar panel system costs around £10,000 and under the government scheme this will pay for itself in less than 10 years, then continue to give you a guaranteed income of around £1200 a year.

“The income is based on energy generated, irrelevant of its use in the home. This means that the homeowner will get paid for making electricity and will also get free electricity during the day all the time that the solar panels are generating power.”

“The government is presently reviewing the current scheme and my advice to anyone considering purchasing solar panels is to make hay while the sun shines! If you get panels installed in the near future you will still qualify for the generous feed in tariff rate which is guaranteed for 25 years.”

0845 009 8642

Aluminium recyclable – a sustainable solution

With ‘eco’ and sustainability issues often being at the top of the global ’green issues’ agenda, the building industry is now more than ever under close scrutiny. The aluminium industry is making a positive and proven contribution and global recycling rates are high, up to 90% for construction and transport applications against 60% for beverage cans.

The fact that 100% of aluminium can be recycled at the end of its design life creates an aluminium bank for re-use in the future and 5% of the original energy required from primary extraction is required at re-smelting. Aluminium can be recycled over and over without loss of properties, ensures that the high value of aluminium scrap remains a strong incentive and financial impetus for recycling. This can only benefit future generations by conserving energy and saving up to 95% of the energy required for primary production, therefore avoiding corresponding emissions, which include greenhouse gases.

The main uses of aluminium are evident in the construction of windows, doors, curtain walling and facades. These can be seen across many types of building from a local high street glazed shopfront to the superstructure of a stadium or flagship shopping development.

Aluminium’s formability, high strength-to-weight ratio, corrosion resistance and ease of recycling make it the ideal material for a variety of building applications. Commercial windows and doors must meet a myriad of functions and be environmentally sustainable, be weather resistant, secure and be energy efficient.

Recognising the importance of the sustainability debate, Comar Architectural Aluminium Systems has the Comar 5P.i. ECO window system, which offers the cradle-to-cradle properties of aluminium, as well as answering current demands. Comar 5P.i. ECO has just passed BS7950 at BRE, which provides compliance with Secured By Design. The weather test BS 6375 provides even more reassurance: air permeability passed at 600Pa, water tightness at 750Pa, wind resistance at 2400Pa and design safety at 3600Pa. Comar 7Pi HSD, a horizontal sliding door system also meets ever increasing demands for energy efficient building materials, this system has been developed for applications where high specification and elegant solutions are a key design consideration eg, offices, schools, hospitals and apartments. The sliding system has been rigorously tested in wet and sandy conditions, borne out with over 200,000 open/close cycles.

Both systems incorporate the trademarked P.i thermal efficiency providing low U-values. Pi is a 20mm-35mm polyamide strip manufactured from reinforced glass fibre, which separates the inner and outer profiles, creating an extremely effective thermal break. These are backed up by Comar’s technical department, offering project by project U-value support.


Solar comparison website

CompareMySolar has the goal to make the solar-energy market easy and accessible for all consumers.

The company’s website calculates the solar potential for individual roofs, and uses customer preferences to present the best options for solar systems and installers. CompareMySolar allows consumers to invite up to three installers for a free and non-obligatory site visit, and provide them with personal phone advice about going solar.

The company provides solar installers with a tool to position themselves in the market though their level of experience, customer satisfaction and quality of materials. By incorporating feedback from consumers installers can build a good reputation online.

All MCS accredited installers can join the network. CompareMySolar gets paid a fee by installers that have joined us once they sell a solar system to one of our customers. This does not result in higher system prices, as the company lowers installers’ marketing costs and increases their conversion rates through site visits with consumers that proactively choose them, CompareMySolar said.

The website launched in November 2010 in the United Kingdom, the Netherlands and Belgium.

Noise proofing

Green Glue Noiseproofing System is an easy to apply and cost-effective system that can help reduce the pervasive noise in urban dwellings.

“The system is designed to help protect the sanctity of residences by keeping noise out,” said Mark Darby, global sales and marketing manager, acoustics, for Saint-Gobain Performance Plastics. “Green Glue technologies come together as a system to decrease noise transmission, offering the most effective and efficient soundproofing results available on the market today.”

Green Glue Noiseproofing Compound is a viscoelastic product that significantly dampens noise transmission by converting sound vibration into small amounts of heat. When applied as a constrained layer between two sheets of plasterboard, plywood or other building substrate, Green Glue Noiseproofing Compound reduces noise transfer from one room to the next by as much as 90%, including low frequency sounds that are normally resistant to soundproofing. The compound comes in easy-to-dispense tubes that can also be used with caulking guns for quick dispersal.

Green Glue Noiseproofing Sealant plugs up gaps and cracks in walls and ceilings that are easily overlooked but which contribute significantly to noise transfer. When applied along wall and ceiling edges, the sealant can prevent these cracks from leaking noise and help maintain a high level of sound isolation.

Both the Green Glue Compound and Sealant are water-based, non-toxic, has only a minimal odour, and is UL Environment certified as Mould Resistant per ASTM D3273.

Green Glue Noiseproofing Joist Tape eliminates noise when foot traffic causes sub-flooring and joists to rub together. Older homes in particular are subject to natural settling, resulting in creaking noises from foot steps. The Joist Tape acts as a sound isolating buffer when applied between joists and sub-flooring, and its low thermal conductivity improves energy efficiency.


New energy saving range

Sidey has developed the SolarthermPlus range

Steve Hardy, Sidey’s commercial sales director said: “Our SolarthermPlus range consists of smart sashes, superior composite doorsets, curtain walling, fire doors, KitFix System for factory fitted windows and doors and Scratchgard, our unique glass protection system. All of which offer a unique, revolutionary opportunity to inexpensively enhance building performance and meet code for sustainable homes levels 3, 4, 5 & 6 and ‘retrofit for the future’ projects.”

The Government stipulates that by 2016 (2013 for the social sector) all new homes will be zero carbon rated (code level 6). To achieve that standard all windows are required to have up to U-values of 0.7w/m2k and doors require a U-value of 0.8W/m2K or less.

“Innovation is something that is sadly lacking when it comes to fenestration in the UK,” Steve continued. “Same old products being stretched this way and that to meet significantly changing requirements. What about integrating photovoltaic’s into ‘dead spaces’ in your curtain walling and integrating blinds into your windows for solar shading while protecting them from damage from enthusiastic students. Then there are highly robust colour options that are significantly more cost competitive than powder coated aluminum, while achieving hugely better U-values or if it has to be aluminum, then aluminum windows and curtain walling that can achieve a U-value as low as 0.8 and 1.0 W/m²K respectively.

“The SolarthermPlus range shows our commitment to innovation and the future of the industry. By developing new product innovations that offer competitive solutions to increasingly onerous demands for thermal efficiency we can help to secure our customers future.”

Sidey’s SolarthermPlus range is available now and offers some of the lowest U-values in the industry – 0.7w/m2k, superior acoustic performance, cost effective solar shading, RAL colour, BS colour and woodgrain finishes and re-glazing options.


New energy saving range

Wrekin Windows is stressing the importance of ‘sustainable efficiency’ at this year’s CIH exhibition.

Visitors to stand C149 will be able to see Wrekin’s new window range, fabricated from RECO22, the 100% recycled window profile system.

Available in a triple-glazed bead and featuring a centre pane U-value of as low as 0.8W/m2k, Wrekin Windows’ new range delivers significant in-life energy and CO2 savings.

John Williams, sales director at Wrekin Windows, said: “The new window range fits perfectly with our emphasis on ‘sustainable efficiency’ for social housing projects. We have to be realistic and recognise that budgets are under real pressure and social housing providers have to make tough choices in the years ahead.

“The lower level of Government funding that is still available for social housing refurbishment is increasingly tied into achieve energy efficiency and carbon reduction targets.

“With a full listing in the BRE Green Book live, our new window system creates just 6% of the carbon emissions during extrusion as a comparable profile made from virgin PVC material, giving social housing specifiers a low maintenance, low carbon window option.

“Efficiency savings are vital and price is an issue for all procurement professional but, in the social housing sector, it is more complex. You cannot just swap window systems from one property to the next, or one estate to the next, without running into serious long term issues for maintenance and replacement cycles.

“Because we are dedicated to this sector, we understand these realities better than any other window or door provider, especially those companies that have jumped on the public sector bandwagon in the past few years.

“That is why professional procurement people in the social housing sector are working with specialist suppliers, like Wrekin Windows, to achieve truly sustainable efficiency.”


Transparent Photovoltaic Cells Turn Windows Into Solar Panels

A new class of transparent photovoltaic cells has been developed that can turn an ordinary windowpane into a solar panel without impeding the passage of visible light, scientists said Tuesday.

The cells could one day transform skyscrapers into giant solar collectors, said Richard Lunt, one of the researchers on the project.

“We think there’s a lot of potential to be able to integrate these into tall buildings,” Dr. Lunt, a postdoctoral researcher at the M.I.T. Research Laboratory of Electronics, said in an interview.

Geoffrey Supran/M.I.T. Richard Lunt, a researcher at the Massachusetts Institute of Technology, demonstrates the transparency of the new solar cell.

Previous attempts at transparent solar cells have either failed to achieve high efficiency or blocked too much light to be used in windows. But the new cells, based on organic molecules similar to dyes and pigments, are tailored to absorb only the near-infrared spectrum and have the potential to transform that light into electricity at relatively high efficiency.

The current efficiency of the prototype cells is only about 2 percent, but some basic modifications, like stacking the cells, could increase efficiency to around 10 percent, Dr. Lunt said.

The largest challenge in developing commercial applications for the new solar cells will be longevity. The cells could be packaged in the middle of double-paned windows, which would provide protection from the elements. But the longevity of the cells would still need to approach the life span of the windows themselves, which would not be replaced for decades.

“To make this thing truly useful, you do need to extend the lifetime, and make sure it reaches at least 20 years, or even longer than that,” said Vladimir Bulovic, a professor of electrical engineering at M.I.T. who collaborated on the development of the cells.

Mr. Bulovic said that previous work to extend the life span of organic light-emitting diodes, or LEDs, which share properties with the organic solar cells, indicated that the problem of longevity was not an extraordinarily difficult one.

“It appears at this point that this is an engineering problem,” he said. “I would expect that within a decade those will be solved issues.”

If the cells can be made long-lasting, they could be integrated into windows relatively cheaply, as much of the cost of conventional photovoltaics is not from the solar cell itself, but the materials it is mounted on, like aluminum and glass. Coating existing structures with solar cells would eliminate some of this material cost.

If the transparent cells ultimately prove commercially viable, the power they generate could significantly offset the energy use of large buildings, said Dr. Lunt, who will begin teaching at Michigan State University this fall.

“We’re not saying we could power the whole building, but we are talking about a significant amount of energy, enough for things like lighting and powering everyday electronics,” he said.

The Center for Excitonics, an Energy Frontier Research Center financed by the Department of Energy, provided funds for the research. A paper describing the technology behind the cells will appear in the next issue of the journal Applied Physics Letters.