Getting Window Design Right
3 November 2014
Factors to consider in window design
Research by Eurocell indicates that one of the main criteria for homeowners when choosing a window design remains aesthetics. The feedback indicated that they felt selecting a design that stands out from the crowd was one of the best ways of adding kerb appeal and therefore value to their home.
The research also highlighted that the main issue facing homeowners was that most window systems in the UK were designed over 10 years ago, and have the same dated sculptured or curved bead profile.
At an investment of £3m, Eurocell therefore set about developing Modus® as a clean-sheet design. Available with three stunning sash style options and eight product types, it offers distinctly different, contemporary aesthetics that rival timber and aluminium, whilst having better looks than all existing PVC-U windows.
Getting window design right once depending on choosing the right material. Timber for a traditional aesthetic and aluminium for refined sightlines. However, advances in the PVC-U industry means that latest profile designs rival the look of timber and performance of aluminium. This has also been helped by innovation in woodgrain and solid colour foils.
As a result, around 9 out of every 10 windows chosen by homeowners in the UK are PVC-U. The material now offers the same design capabilities and aesthetics as other materials and, for instance, is regularly specified for properties in conservation areas.
It is important to consider this aspect in terms of window design:
• Updated Building Regulations Part L (April 2014) require a U value of 1.40w/m_K for windows and external doors in both new and existing properties. This is equivalent to a WER (Window Energy Rating) of ‘B’.
• If you are considering a zero carbon build you need to be choosing a window design that achieves a U value of 0.8w/m_K, or better
• 0.8 u value (or better) windows are an important element in passive home design. These use solar energy to provide heating, cooling, and lighting for a house.
The 75mm multi-chambered design of Modus is capable of achieving a U-value of 0.7 from a standard argon gas-filled triple glazed unit, without the need for expensive, esoteric-specification glazing units. Similarly, a U-value of 1.1 can be achieved using a double-glazed unit, well within Building Regulation requirements.
When maximising energy efficiency of a window in a new build always try and use cavity closers. They are the simplest, most effective way to seal cavities around wall openings and provide a rigid window or door frame acceptor. As well as creating a rigid template for bricklaying and window or door installation, they enhance thermal efficiency, create a damp-proof course and prevent cold bridging. Take a look at: www.cavalok.com
An ‘A’ rated window design has an Energy Index of 0 or above. This means that it loses no energy and could actually allow solar energy into the house therefore achieving further savings.
Safety glass will need to be factored into your window design if they are in a critical area and here is a general list of when it is required:
• Glazed areas within a window below 800mm from floor level
• Any window that is 300mm or less from a door and up to 1500mm from floor level
• Within any glazed door up to 1500mm from floor level
See Approved Document K (2013 edition) for more information.
The direction your window faces has a lot to do with choice of design.
If it’s a south facing window you may want to consider a window that allows you to fully open each sash to allow sufficient ventilation. For even more ventilation, choose a French window design – this allows both sashes to fully open without the need for a centre mullion – providing maximum opening.
A coated glass on south facing windows may also be a good way of preventing excessive solar gain, should you want to keep windows closed on high pollen days.
Facts and figures about PVC-U• Over 85% of windows fitted in the UK are PVC-U and the material is therefore generally accepted as the nation’s favourite.
• PVC-U has been assigned the same sustainability credentials as timber – the BRE (Building Research Establishment) recognised this when it awarded PVC-U an ‘A’ rating for sustainability with residential and A+ for commercial developments in its Green Guide to Specification.
• The BRE Green Guide also recognised that PVC-U achieves a Reference Service Life (RSL) rating of at least 35 years and can be recycled up to 10 times without degradation in quality - effectively giving the raw material a life expectancy of 350 years!
• Eurocell currently has the largest post-consumer recycling facility in the UK with a capacity to recycle up to 12,000 end-of-life PVC-U window frames per week – that’s over 500,000 old windows each year! The recycled material is used to make new, energy efficient window products.
• Modus® utilises 50%** post-consumer recycled PVC-U as standard (and up to 100% is available as an option)
Modus – the UK’s first fully integrated window and door system
Modus is a brand new PVC-U window system from Eurocell that is available with three sash design options - standard rebate, slim rebate and fully flush sashes.
The slim rebate and fully flush casement windows provide a much wider range of design aesthetics and a genuine value for money alternative to aluminium and timber products respectively.
For those that choose the standard sash, it creates an aesthetically superior solution to traditional PVC-U windows.
Being a fully integrated design allows the one Modus system to be used to manufacture eight different window designs:
• standard sash casement windows
• slim rebate casement windows
• flush sash casement windows
• reversible windows
• tilt & turn windows
• entrance doors
• French doors
• composite entrance door frames
That’s useful in terms of window design because it allows homeowners to mix and match styles whilst still retaining the same frame profile.
For example, you may choose a fire escape (egress) window for safety or tilt and turn for easy cleaning on the first floor, but plain casement on ground floors. Modus allows you to do this whilst using exactly the same frame profile – creating a fully coordinated look across the property in the process.
Modus is available in nine solid and woodgrain effect colours from stock. All standard colours are available with white internal finishes to create a light and airy living environment. A further range of 30 solid and woodgrain effect finishes is available, plus colour both sides.
For a differentiated, premium look Eurocell offers the Architectural range. Consisting of three specially selected metallic options Quartz Platinum, Asphalt, Sapphire Silver and Anteak, a premier woodgrain finish, the architectural range adds an affordable touch of class to any property.
Research carried out by Eurocell indicated that the top four priorities for homeowners (in order) when choosing windows are:
1. Aesthetics – is it going to add kerb appeal to my property
2. Price – most consumers put aside around £5k to spend of replacement windows
3. Energy efficiency – does the window help us make savings on heating bills
4. Security – how do I know when it is a ‘secure’ window
Terminology• Post-consumer PVC-U – first generation PVC-U windows installed in the 80’s and 90’s that have reached the end of their life and are now being recycled. These windows are being replaced because, for example, the double glazed units fall below modern thermal performance standards, or the property owner is looking for a fresh, new look.
• End-of-life PVC-U – this is the same as above, but can include PVC-U from other sources apart from window frames.