Effective Solar Shading – Selecting the right blinds to prevent overheating and glare

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Content supplied by Caribbean Blinds (UK) Ltd

Whether you’re building an extension, renovating your existing home or embarking on a new build, one thing is guaranteed, it will include large expanses of glazing in the guise of sliding/folding doors, panoramic windows and sky/roof lights.

This type of glazing brings many advantages to a building; along with providing an unhindered view out, it creates a feeling of openness and endless space and allows a room to flood with natural daylight, all important factors for well-being and the enjoyment from an area.

However, glazed areas of any description are the single biggest cause of excessive solar heat gain and unwanted glare in homes, resulting in a space that is uncomfortable and unbearable to be in – too hot and too bright. An all glass room (glass box / conservatory), even fitted with solar control glass, can easily exceed internal temperatures of 40oc on a warm summers day.

Why buildings get so hot

1. The suns energy enters the earths atmosphere as shortwave (near infra-red) radiation

2. Glazing is virtually transparent to this shortwave radiation and subsequently the suns energy easily passes through these transparent areas in buildings

3. When inside a building, the suns energy is absorbed by fixtures, fittings and furnishings, including internal blinds, curtains and plantation shutters

4. It is then re-radiated as infra-red (heat) rays which are at a different, longer wavelength

5. These longer wavelengths cannot pass through glazing and therefore remain trapped in the building, causing it to heat up

The above process is often referred to as the greenhouse effect.

Say goodbye to unwanted solar heat gain (and glare)

External solar shading systems create a physical barrier between the suns energy and glazing, blocking upto 96% of the incoming shortwave radiation as the majority of the suns energy is either reflected, in the case of lighter blind fabrics (hence why cricketers wear white) or absorbed by the shading material (darker colours).

By stopping shortwave radiation even reaching the glazing, exterior shading systems block excessive (unwanted) solar heat gain, preventing a room from overheating. In fact, appropriately sized and positioned external blind can reduce interior room temperatures by more than 10 degrees centigrade on even the hottest of summer days which in turn can cut the energy consumption otherwise needed to cool down a hot room by over 80% – natural air conditioning guaranteed!

Furthermore the materials utilised on external sun protection systems still admits diffused daylight through allowing a space to flood with natural ‘glare free’ light and the view & connection is kept to the outside.

Insulation properties too

Windows are responsible for the largest portion of heat lost from building. In fact, even the best quality glazing loses heat more quickly than an uninsulated cavity wall. Air trapped between the glass and fabric on sealed external roller blinds and roof blinds creates an additional layer of insulation to the glazing during colder months, helping to slow heat loss, keeping a room warmer and reducing the need to switch the heating on.

Heat loss can be improved (slowed down) by almost a third when an external sealed blind is in combination with a double glazed window, common in many homes and for older single glazed and first generation double glazed windows heat loss can be slowed by upto a staggering 50%, improving the performance of these window types in line with a modern efficient double glazed unit.

The importance of automation

External shading systems do not lower internal room temperatures, they prevent them from rising. Therefore it is important they are motorised and equipped with intelligent sensors that monitor the external climatic conditions so they can automatically position themselves based on heat/light levels and desired occupant requirements, to provide maximum thermal and visual comfort along with energy saving function.

Types of exterior shading solutions

The most commonly seen and popular type of external shading system is the retractable folding arm patio awning. Mounted on the façade normally above patio doors of all types (sliding, folding, traditional) they project out creating an overhang that regulates solar heat and light to the adjoining internal room, whilst also providing a roof to the terrace that offers shade and shelter for alfresco living – outdoor living & solar control in one solution.

Tensioned roof blinds also referred to as conservatory awnings run over along with conservatory roofs, all types of flat skylights and rooflights, whilst external screens & roller blinds run down in front of all types of vertical glazing including sliding and folding doors.

Louvered pergolas are a relatively new type of shading system to the UK. When installed abutting a property, the rotating roof louvers (like a venetian blind but mounted horizontally) can follow the direction and angle of the sun to provide precise sun control along with ventilation through.

Where there is glazing, you need external shading.

Exterior solar shading solutions are the only effective way to manage the entry of solar heat and light into a building to provide a thermally & visually comfortable indoor space, that remains cool in the summer and warm in the winter, free from glare all year round, with the view out maintained and minimum energy demand on installed cooling, heating and lighting units.

Summary – the key benefits of external blinds, awnings and outdoor shading solutions

  • REGULATE SOLAR HEAT GAIN > Upto 96% of incoming solar radiation is blocked to prevent overheating
  • CONTROL LIGHT LEVELS > Incoming light is filtered to provide an evenly distributed natural light source
  • ELIMINATE GLARE > Glare caused by peak summer and low winter sun is effectively diffused
  • MAINTAIN OUTWARD VISION > The connection and view is kept to the outside
  • PROVIDE PRIVACY > A vision barrier is provided from onlookers and adjacent buildings
  • FILTER DAMAGING UV RAYS > A minimum of 95% of the suns damaging ultraviolet radiation is stopped
  • MINIMISE HEAT LOSS > A thermal barrier is created which helps to retain heat in a building during colder months
  • ENHANCE THE FAÇADE > A striking new dimension and splash of colour is given to the building envelope