Category: Glass and glazing

Condensation

For the glass and glazing industry, the transition from winter to spring and summer to autumn often sees an influx in customers asking why they are seeing external condensation on their windows, especially from those with higher performing, low-emissivity glazing. While some homeowners may see it as a nuisance, external condensation is a tell-tale sign that energy-efficient windows are actually doing their job.

However, if condensation is appearing on the inside surface of your windows or between the panes of double or triple glazing, this is for a very different reason.

You can download our CERTASS Consumer Guide to Condensation below:

CERTASS-CONSUMER-GUIDE-CondensationDownload

EXTERNAL CONDENSATION

External condensation happens because of the dew point – the temperature at which air can’t hold any more water vapour, causing droplets of liquid water to form. When the air next to a piece of glass reaches this temperature (which varies with humidity) condensation forms on the surface.

External condensation is more common with modern, high performing, low-emissivity (low-e) glazed windows, as the outer pane is colder as a result of heat being retained inside the home. With single or older double-glazed windows, more heat is passing through, warming the outer pane and reducing the likelihood of external condensation. An analogy is frost on roofs – those with good loft insulation can remain frosted for a long time, while those without quickly defrost.

Above: External condensation with the tell-tale gap around the edges as shown here indicates your low-e sealed units are performing well.

This phenomenon is more likely to happen in the spring and autumn, when cold morning and evenings combine with high levels of humidity in the air.

Not all panes are affected by early morning condensation, even in the same window. Small differences in the orientation and the position of objects outside, such as trees or a close building, can change the surface temperature of the glass to the point that one pane suffers and another doesn’t.

There is little that can be done to avoid condensation to the outside of the window entirely without specialist glazing. However, its occurrence doesn’t tend to last for long. Once the window pane warms from the sun, the moisture evaporates and the condensation clears. The air movement from a gentle breeze can also help to clear it. You will find that as the weather warms (spring) or cools (autumn) the phenomenon simply disappears.

CONDENSATION IN BETWEEN PANES

Condensation within the cavity of a sealed unit is likely to indicate a failure of the edge seal. You will usually notice a misting or “steamed up” effect inside the gap between the panes of the sealed unit. In this case, the sealed unit has broken down and will need replacing. Sealed units are designed to last many years, but occasionally may break down due to some external factor or a manufacturing default or simply due to age. If your windows are still under guarantee, then you may be able to have your broken down unit replaced under your guarantee.

CONDENSATION ON THE INSIDE

All air contains water vapour, but the amount of water air can hold is determined by the temperature of that air. This ratio is called the relative humidity. Hot air is able to carry much more moisture than cold air, so as the temperature of air rises it is able to hold a greater volume of water. The water comes from everyday activities including bathing, cooking and washing. Even our breathing causes condensation, and this is why your car will steam up when you sit with the windows closed and the fan off.

As soon as warm air, containing vapour, hits a cooler surface, it will condense. This is most obvious on windows, mirrors and wall tiles, but condensation can also gather on walls and ceilings and often go unnoticed. The only way of preventing condensation is to provide ventilation. The warm air, containing the water vapour, will rise and circulate around the room until it finds a cooler surface, unless we let that air out and some cooler air in.

In order to ensure that there is good ventilation in your home, a change of air is recommended in all rooms of the house at least once a day, and ideally more often. Install extractor fans at the sources of water vapour such as the bathroom and kitchen. Increasing the room temperature so that the air can hold more water vapour without condensing can also help.

AXA Insurance helpful video on how to prevent condensation and mould in your home.
  • Ventilate your home regularly and open your windows. If you have trickle vents, leave them open.
  • Fit an extractor fan, and use it: ensure your bathroom fan is working while you are bathing and showering, use your kitchen extractor fan when you are cooking.
  • Avoid drying washing indoors. If you have a tumble dryer, ensure it is properly vented or use a self-condensing model.
  • If the condensation still remains a problem, use a dehumidifier.

Want to know more technical details about condensation? We recommend this online article from St Gobain here. Plus AXA Insurance have put together a thorough guide about condensation – what causes it and how to stop it. If you need any further help then give us a call on (020) 8868 1133 or drop us an email â€“ we look forward to hearing from you soon!

The Guardian Warm Roof

Re-invent your existing conservatory with one of our super fully insulated solid roofs by market leader Guardian.

 

THE PROBLEM
If you already have a conservatory, you’ll know how the outside temperature and weather conditions can effect the overall comfort of your room and how it’s used. If you’ve inherited an older conservatory through a house move for example, you may find that it’s an unusable space during the winter or hot summer spells. A common remark we hear is that “my conservatory is too hot during the summer and far too cold in winter.” A new Guardian Warm Roof could therefore be the perfect solution for you.

THE SOLUTION
The Guardian Warm Roof is a revolutionary step forward in home improvement – a high performance, lightweight roof system that has been designed to replace your existing glass or polycarbonate roof or be installed as an alternative on your new conservatory.

INSTALLATION BY RUISLIP WINDOWS. BEFORE: Glass conservatory roof with decorative cresting. AFTER: New Guardian Warm Roof installed – a complete transformation!

Fully tested and approved to all thermal and structural standards, the Guardian roof is a high performance insulated roof system comprising of a pre-engineered lightweight frame, two layers of rigid insulation board, internal insulated plasterboard, exterior grade plywood and a vapour membrane. Altogether this creates a more thermally efficient living space than your existing conservatory, keeping the warm air out in the summer and preventing the heat from escaping in the winter.

  • The solid roof will help you to maintain a consistent interior temperature.
  • Your room will be quiet and comfortable all year round.
  • Your new room can now be fully integrated into your ground floor living area.
  • It will give you the extra space you have always wanted.

Designed to retain the conservatory’s original windows, doors, frames and walls, the Guardian Warm Roof System is fully tested and approved to all thermal and structural standards.

(1): Choice of tile nishes. (2): Membrane. (3): Exterior grade plywood. (4): 25mm high performance insulation. (5) 40mm high performance insulation. (6): Timber battens. (7): 72mm high performance insulated plasterboards. (8): Rafter.

By removing your old conservatory roof and replacing it with a new insulated tiled roof, you’ll completely change the appearance of the rear of your home and garden. Now your conservatory will more closely resemble a proper extension and by choosing tiles that match your house you’ll be getting all the benefits of a ground floor extension along with the convenience and style of a conservatory.

If you’d like more details about the Guardian Warm Roof system and how you could transform your existing conservatory, download our PDF brochure here >> or contact us to discuss your requirements in more detail. We’re here to help! 🙂

Double glazing -v- triple glazing: what’s the best option?

Triple-glazing is often marketed as a better option than double-glazing, especially when it comes to thermal insulation. But is this really the case?

 

If you look at the websites of the big nationals for instance, you could be forgiven for wondering why so many companies are still even selling double glazing when triple glazing appears to be so much better at insulation and soundproofing your home! Here we attempt to debunk many of the myths that surround triple glazing, and clarify the facts to help you make an informed decision that’s right for you.

Example of a triple glazed sealed unit and a double glazed sealed unit.

While it’s true that triple-glazing does offer some benefits, it may not be the best or most economic solution for you.

Triple glazing is a better insulator for your home than double glazing.
The energy performance of windows is measured in U-Values. Lower U-values = a more energy efficient window. Traditional single glazed windows can have a U value in excess of 5. Building Regulations now stipulate that modern double glazing should have a U-value of no less than 1.6.

U-Values for older double glazing used to be much higher. However in recent years the manufacturing process has been greatly improved to provide much more energy efficient units. These improvements have been brought about by the introduction of wider cavities between the two glass panes, low-emissivity coatings being added to the glass to stop heat escaping (glass such as Pilkington K or Planitherm Softcoat Total), the cavity being filled with an inert gas (usually argon) and the use of warm-edge spacer bars (instead of aluminium).

Triple-glazing enables window manufacturers to achieve U-values of 1.0 and lower. So yes, triple glazing can enhance heat retention.  But such U-values are really only of benefit when they are installed into an overall energy saving build, such as in a low energy house or a “passive house”.  Where windows are being fitted into a standard build or as part of a refurbishment project then sealed units offering U-values as low as 1.1 are preferable and easily achievable with double glazing.

With the exception of perhaps the northern reaches of Scotland, the rest of the UK is simply not cold enough to warrant the use of triple glazing. Scandinavian countries such as Iceland, Sweden, Norway, Finland and other far northern countries use triple glazing because temperatures such as -20° C can be quite frequent. Highly energy efficient windows and doors, triple and sometimes quadruple-glazed are absolutely necessary to help reinforce the fabric of the buildings against the cold.

As far as the UK is concerned, there are many who argue that triple glazing simply doesn’t make sense in our climate. It is more costly to produce, produces much heavier sections and has an embodied energy approximately 50% higher than double glazing. Why would home owners pay more when good double glazed windows would easily tick the box?

Triple glazing is a better sound insulator than double glazing.
One of the biggest selling points of triple glazing has been its ability to reduce noise and outdoor sound. The thickness of the glass used is one of the three key elements of the sound insulation. Different thicknesses of glass will block a different frequency, so a combination of panes of varying thickness is more effective at keeping noise out. This is known as asymmetrical glazing. However, (and somewhat ironically!) most fabricators currently appear to offer triple glazed units with standardised cavities and glass thicknesses.

The second key element is the size of the gap between the panes. The larger the gap, the better the overall sound insulation effect. Finally the use of an acoustical resistant gas to augment or replace the inert gas (usually argon) will effectively help reflect noise away.

If sound insulation is important to you then it would be worth considering acoustic glass sealed units (such as Pilkington Optiphon or St Gobain’s acoustic glass, both of which are laminates) or even secondary double glazing instead. Secondary glazing will have a much greater air gap than can be achieved in triple glazing, and can achieve great noise reduction at considerably less cost.

In conclusion – For

  • Triple-glazing offers low U-values suited to specific low-energy and “passive house” projects and can return the value of your investment when fitted as part of these specifications.
  • If asymmetrical glazing is used together with acoustic glass, some noise reduction can be achieved.

In conclusion – Against

  • Higher cost.
  • Reduced light penetration due to additional layer of glass.
  • Minimal savings in energy bills in comparison to the higher cost.
  • Benefits such as noise reduction and solar control can be included in double-glazing for less than the cost of a standard triple-glazed unit.
  • Overall greater weight than a double glazed unit could pose problems for your windows – sashes dropping can be an issue.

Please do not hesitate to contact us for any further information. We look forward to hearing from you and hope to see you soon! 🙂

What is smart glass?

Glass has got intelligent. And we think it’s all the better for it.

Generally used in conservatory and lantern roofs, the term “smart glass” or “intelligent glass” usually refers to the new generation of glass systems that feature additional built-in properties. This can include solar control, privacy glass and self-cleaning glass. There is now a growing demand for better performing conservatory roofing systems, both for brand new installations and for the emerging replacement sector. Glass is at the very heart of the thermal and acoustic performance of any conservatory and smart glass is not only far quieter but can also regulate temperature so your conservatory can be used all year round. It can reflect unwanted heat and glare from the sun in the summer, yet will also help to retain warmth during the winter months, and is almost three times as efficient than standard double glazing.

Smart glass can also filter out harmful UV rays and use self-cleaning technology, reducing the frequency of cleaning required and keeping your roof looking better, for longer.

TYPES OF “SMART GLASS” AVAILABLE

Pilkington Activ™
This was the world’s first self-cleaning glass. It’s basically the same as conventional glass, except for a unique permanent dual action coating. It works in two ways: first it uses daylight to break down organic deposits (such as dirt) and then uses rain to wash the dirt away. Pilkington Activ™ also dries faster, leaving the glass clean and with less streaks. It’s an ideal solution for conservatory roofs, orangeries, glass extensions, skylights and windows in hard to reach areas. The Pilkington Activ™ range comprises of several different types of self-cleaning glass:

  • Pilkington Activ™ Clear – self-cleaning glass.
  • Pilkington Activ™ Bronze – a tinted self-cleaning glass that combines self-cleaning with solar control.
  • Pilkington Activ™ Blue – a tinted self-cleaning glass that combines self-cleaning with medium solar control.
  • Pilkington Activ SunShade™ Neutral – a coloured glass that combines self-cleaning with superior solar control.
  • Pilkington Activ SunShade™ Blue – an attractive blue tinted glass that combines self-cleaning with superior solar control.

Check out the Pilkington Activ brochure on our website here >>

Dynamic SMARTGLASSÂŽ
This is an exciting new product by Clayton Glass – the industry’s first automatically self-tinting, glass technology for conservatories, orangeries and lantern roofs. In the middle of summer SMARTGLASSÂŽ Dynamic will change from a clear state in the morning to a darker blue one during the day, where solar control and light shading is needed most. Then as the unit cools, it will return to clear at the end of the day and into the night. (This reminds us a bit of those reactions lenses you can have in your glasses!). At all other times of the day and season this glass will offer various semi-tinted states, dependant upon the surface temperature of the glass. In its clear state, this glass offers a similar light transmission to a standard clear glass unit.

SMARTGLASSÂŽ Dynamic by Clayton Glass, shown in its clear and tinted states.

SWITCHABLE PRIVACY GLASS
Almost like magic, this glass can turn from clear to opaque instantly. Truly the stuff of “Grand Designs”, switchable glass is operated by a simple electrical switch, controlling the opacity of the glass from clear to translucent. The opacity is down to a special Polymer Dispersed Liquid Crystal (PDLC) film which includes conductive interlayers and allows you to change the visual appearance of the glass at the flick of a switch.  The latest generation of switchable double glazed smart glass windows combines the benefits of improved thermal performance with the immediate control over privacy and security. The PDLC can be applied to any type or thickness of glass including toughened, laminated and double glazed sealed units, offering a number of glazing solutions for both the domestic and commercial markets.

Now you see it, now you don’t! Switchable glass used in a shower screen to give privacy. Ok, we know it’s not a window or door, but hey, we liked this and think it looks cool!

SOLAR CONTROL GLASS
Excess heat and glare caused by the sun can be a major source of discomfort in some indoor environments, especially those with glass roofs, conservatories or with large glazed areas. The latest solutions for solar control reflect and filter the sun’s rays, allowing natural daylight into the room, but without uncomfortable visual glare. Rooms can be kept cooler during sunny periods, reducing the need for air-conditioning. A range of solar control glass solutions are available, from a number of trusted manufacturers such as St Gobain, Pilkington and Reflex.

Solar control glass can be incorporated into double glazing window with combinations of other glass, such as self cleaning, Low E and decorative glass. Combining solar control glass with Low E thermal insulation in one double glazed unit offers optimum temperature comfort all year round.

Talk to us about the different glazing options that are now available for your home. We hope to see you very soon! 🙂