There are many different glass specifications on the market but generally, these can be split into the following types.
Double Glazed
Standard soft coat glass with Low Emissivity (Low E) glass on the inner pane.
Triple Glazed
An additional pane of glass for improved thermal and noise reduction values. Will cost approximately 20% more than standard double glazing.
Solar Control
Extra coating applied to glass to improve solar reflection and thermal value. Will cost approximately 10% more than double glazed quote.
Noise control
Using an 8.8mm laminated pane. Will cost approximately 10% more than standard double glazing.
Self-cleaning
Outer pane chemically coated to react with rain water and make it viscous (sticky) and therefore carry more dirt away with it. It also activates to allow water to run off quicker. Will cost approximately 10% more than standard double glazing.
Obscure
Stippolyte and Satinovo (sandblasted) designs most popular. Will cost approximately 5% more than standard double glazing.
Toughened
Glass is toughened through heating, which means it breaks into safe chunks when broken, not dangerous shards. This is used in doors and windows near doors or near ground level. Will cost approximately 5% more than standard double glazing.
Laminated
One pane in glazed unit is two pieces of glass laminated together for extra strength. Will cost approximately 15% more than standard double glazing.
Leaded Design
We can apply 9mm lead in a variety of designs (diamond/square/custom) to our glass for a more traditional look.
Georgian bar/insert
We can either put bars inside the glazed unit or at a higher cost, outside the glass on both inside and outside to match the frame.
Internal blinds
Our units can also come with blinds inside the glass.
How to understand how efficient glass is
The easiest way to understand how efficient glass is, is by thinking of it as a ‘heat mirror’. The more effective the glass, the more of a ‘heat mirror’ it is, stopping heat loss by keeping heat inside the house but also keep heat out preventing over-heating.
Self-cleaning glass reacts with rain water making it viscous, carrying away dirt with it. Self-cleaning glass still needs cleaning, just less than standard glass.
Metallic spacer bars conduct the cold easily and cause condensation around the inside edge of the window, which can lead to water gathering inside and damaging plasterwork. Many companies still use metallic spacer bars as they are cheaper. Warm edge composite spacer bars dramatically improve insulation levels and raise energy efficiency ratings. Our windows and doors are all fitted with modern composite or ‘warm edge’ spacer bars as opposed to the inferior metallic spacer bars.
A U-value is a calculation that tells us about the insulating properties of a window or door. The lower the U-value, the better insulation the product provides. The frame (uPVC, timber effect, or aluminium) and the glass have their own U-values. Different specifications of frame and glass have different U-values eg. solar control glass has a lower U-value than standard double glazing. When the U-value of the frame and glass are combined, an overall U-value can be calculated, which is then used to comply with Building Regulations requirements.
All our products comply with Building Regulations U-value requirements as standard. Sometimes an architect will require a particularly low U-value to achieve an overall thermal rating (or ‘SAP’ calculation) for the building they are designing. In this case, we must upgrade the product and glass specification to reduce the U-value.
A Window Energy Rating (WER) is calculated using three criteria.
- Air draught – how much air can pass through the window/door when closed (the less, the better).
- Solar gain – how much heat from outside is transferred inside (the less heat allowed in, the better).
- Solar retention – how much heat from inside is kept inside the building (the more kept in, the better).
Window Energy Rating is measured on a scale from A-G with A being the most energy efficient.
The below are estimates and won’t always be accurate. They are just to give customers an idea of what product might be affordable.
If an average house of windows and doors in uPVC costs £10,000
- – Woodgrain foiled uPVC would be £16,000
- – Timber effect (R9/R7 & Evolution) would be £20,000
- – Smart aluminium would be £20,000
- – Schuco aluminium would be £28,000
- – Going from single colour aluminium to dual colour (different colour inside than outside) increases cost by about 8%.
- – Particularly large glazed units (generally in sliding doors or fixed panes) that are over 4 square metres are more expensive.
