Solar Glass vs External Blinds – Which Is Better?

What are External Blinds & Solar Glass

With the rise in global temperatures and climate change we need to find ways to keep our homes and offices cooler even in more temperate climates like the UK.

Higher temperatures all year round mean buildings with large windows can suffer a greenhouse effect whereby the windows work like radiators creating an uncomfortably warm house or office.

Architects often choose either solar glass or solar shading such as external blinds to comply with Building Regulations Part O introduced in 2023 to tackle overheating.

Solar glass is normal glass treated with a metallic tinted coating to reflect infrared radiation to keep a building cool but which still allows light to enter the room. (Solar glass can also refer to glass with solar photovoltaic modules are laminated into the panes to generate electricity.)

Solar shading can include brise soleil, deep window reveals, louvres, or external blinds.

External blinds are specialist blinds designed to be installed on the exterior of a building. Generally exterior blinds are venetian style (with adjustable metal louvres) or retractable screens made of an open weave fabric. They block the sun’s rays but also allow light into the building.

How Do Costs Compare?

There isn’t a great difference in terms of cost between solar glass and external blinds.

The cost of solar glass depends how big your windows are, who installs it for you and the tint you choose.

In the same way, the cost of external blinds also depends on specifications such as the size of windows and the fabric you choose.

Increasing UV Protection

Super insulation can slash heating and cooling energy needs by up to 50 per cent, a massive cut in carbon emissions.

You can put insulation under the roof, external walls and floor, ideally forming a continuous barrier to maximise its effect to reduce heat loss and minimise the energy demand.

It can also be placed in internal walls to increase sound proofing and again help to reduce heat loss.

Solar Blinds & Shading

Like external blinds, solar glass intercepts and reflects sunlight before it reaches the glass and blocks solar heat and minimises glare.

Therefore, both provide excellent UV protection, helping to protect soft furnishings inside a home or office.

Reducing Heat

Both are excellent choices to keep a house or office cooler, though external blinds have been shown to be more effective at reducing temperatures (though this depends on the climate, the window’s orientation and how dark a shade you choose).

We measure the amount of solar gain through a window using a value called Solar Heat Gain Coefficient (SHGC) known as G-value for short.

A G-value is calculated from the direct energy transmitted through the glass plus the energy absorbed by the material and radiated internally into an enclosed space. So, a value of 0 means all solar energy is blocked and 1 is full transmittance of energy.

Using the G-value, external blinds are more effective, often measuring 0.2 or less compared to solar glass which generally achieves 0.3.

Put simply, using external blinds on a building results in a drop in temperature of up to five degrees Celsius compared to solar glass which achieves a drop of two degrees Celsius, or more in a hotter climate.

Fixed or Moveable

Solar glass is fixed in place and therefore you don’t have any flexibility to choose the light levels, whereas external blinds can be raised or lowered depending on how much heat and light you want to allow into your room. This is especially beneficial in winter when the blinds can be raised to take advantage of solar gain from the sun to heat the house.

External blinds can also be very easily retrofitted to a building compared to solar glass which is much more disruptive, not to mention costly, to fit.

Quality of Light

Even when the blinds are lowered, the open weave of the fabric allows occupants to look outside and light to come in while blocking 80 per cent of the heat.

However, solar glass is tinted and so impacts the quality and colour of light coming into the house.

Aesthetics of Glass vs External Blinds

There is no doubt that solar glass can create a very modern and sleek look although its unusual tints are not to everyone’s taste.

In the same way, many architects choose external blinds because they also give a contemporary look and feel to homes and offices.

Blind fabrics also come in different colours and shades allowing more of personal touch than solar glass.

Personal Choice and Needs

While there isn’t a significant difference between solar glass and external blinds in terms of cost and effectiveness, it is very dependent on the size of the windows and other specifications including personal choice.

Contact our team of experts who are always on hand to help you look at key factors such as cost, look and sustainability.