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Waverley RIBA-accredited CPD

The 10 most frequently asked questions in our CPD presentations

By: Oli Birch Category: Blinds

At the start of 2022, we introduced a brand new CPD presentation ‘Improving Sustainability through Performance Solar Shading.

Originally delivered to individual architect practices, we successfully launched the session as a webinar in October last year.

Feedback has been incredibly positive on both formats and our team have thoroughly enjoyed presenting, engaging with the audience during the lightbox demonstration and answering any questions that have popped up.

Speaking of questions, we keep a list of everything that is asked during the presentation, and have decided to answer the top 10 most frequently asked questions here.

1. What is TV value?

TV value is a percentage measurement of the total amount of light passing through a blind and includes both the amount of light that passes through the ‘holes’ in the fabric and the yarns. This value is often confused with the ‘openness’ factor, which is also a percentage but is a measurement of the total area of the ‘hole’ in a blind.

2. When using metallised blinds, is there any problem with heat trapped between the blind and the window?

No. Solar heat gain occurs when the short wave radiation, in the form of light coming from the sun, passes through the glass into the building and is absorbed by the objects inside depending on their colour.

These objects then re-radiate this into the room as long wave radiation, and because of the change in wavelength cannot pass back through the glass. The metal coating on the blind reflects the light back through the glass before it is absorbed.

If the blind could have 100% reflectivity there would be no heat build-up, but in practice the best reflectivity levels that can be achieved are around 80-85%, and therefore a small amount of heat build up occurs.

However, this is generally considerably less than a non-metallised fabric (although some white fabrics achieve similar reflectivity but their glare control performance is abysmal).

3. How is the metallised fabric made and what is it composed of?

The basic cloths used are the same for both non-metallised and metallised fabrics, with the aluminium coating being applied after the cloth has been woven by a separate process.

The best performing fabrics have the aluminium coating applied by a condensing process which gives an extremely uniform layer, enhancing its performance, and also ensures superior adhesion to the base cloth. Cheaper quality fabrics have the aluminium layer sprayed on, resulting in ‘highs & lows’ impeding performance, and tend not to adhere to the base cloth so well.

4. Is there a cost difference between plant-based materials and others?

Yes, they tend to be more expensive than the cheaper manmade fibre products available, but are comparable with higher quality ones. However, glare and solar gain performance tend to be inferior verses metallised textiles and PVC polyester textiles. Bio yarns are a newer development though, so performance and cost are likely to improve as time goes on.

5. How sustainable are features like decorative coil mesh?

They’re made of metals like steel, copper and aluminium, meaning they are highly durable and easily recycled at the end of their life. Therefore, they’re very sustainable. Aluminium, for example, is said to be one of the easiest and most cost effective materials to recycle, with around 75% of all aluminium ever made still in circulation. 

6. Why has it taken so long for metallised fabric to become known in the UK?

Difficult one to answer. Metallised blind fabrics were first manufactured in the 1960’s but have not really become widely used in Europe and UK until recently. Historically overheating and glare control in our buildings has not had the consideration or emphasis as it has now, so simple blind fabrics have been deemed sufficient window covering.

7. How much heat gets re-radiated out of the window with a white blind?

This depends on the type of yarn and weave, but some white coloured blinds can achieve similar reflectivity as a metallised blinds. However, their glare control and view through performance is significantly inferior, as previously mentioned.

8. What is the life expectancy of a blind?

This will depend on the blind fabric, how often they are used and how well they’re maintained. But according to US website blinds.com, the average lifespan for a standard blind is around 7-8 years.

9. Does colour affect the view through the blind?

Yes. Darker colours are easier to see through than lighter/white fabrics. Colour is always an important factor to consider when making a decision about your blinds.

10. Do you have any more information on how blinds should be maintained?

As they’re made up of one continuous sheet of fabric, roller blinds are very easy to maintain. The fabric can be dusted and wiped thoroughly and the simple operating mechanism means they’re inherently reliable.


If you’d like to learn how metallised blind fabrics can improve building efficiency and assist with achieving environmental accreditation then follow this link to book your place for our webinar on Tuesday 12th September, or contact us if you have any further questions.

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