Condensation on your windows

At this time of year do you suffer from condensation on your windows in bedrooms?

We have noticed it in a lot of homes even with newly installed double glazing and this shows a potentially large problem or two.

Take for instance the windows. If they are double glazed there is no way that they should have condensation on the inside pane of glass. If they are affected by condensation it is probably because the gap between the glass is not sealed and filled with inert gas like Argon it is just filled with normal air (not even dried filtered air) and this is very common in Portugal.

For independent information, we recommend you take a look at. http://www.double-glazing-info.com/Choosing-your-windows/Air-or-Argon-gap

A double glazing window comprises two panes of glass, separated by a spacer bar and seals to create a hermetically-sealed environment. The cavity width between the two panes, air or another gas filling used and the type of spacer bar, are all key factors in the unit’s final energy, solar and acoustic insulation properties. Which dictate condensation or not!

The cavity is filled under vacuum conditions with either dehydrated air or an inert gas to improve insulation and prevent condensation within the unit. Depending on the gas filling used and the type of window, the cavity width for a double glazing window is generally between 4 to 20 mm.

Condensation on your windows, castelo construction, portugal builder,builder in Portugal

Condensation on your windows

The recommended cavity width for Low E energy saving double glazing window when filled with dehydrated air is 16mm – and 14mm when the cavity is filled with argon gas.

Less heat transmission with double glazing window and a warmer home

The physical properties of the dehydrated air used in the cavity means that it transmits (ie loss) less heat by convection or conduction than normal air. This is because the molecules of dehydrated air are relatively immobile, and therefore have a ‘lower thermal conductivity’. The same physical properties of dehydrated air also give it lower acoustic conductivity, for improved sound insulation.

If normal atmospheric air is used the performance of the panel’s is further reduced.

Double glazing window energy efficiency can be further increased by substituting dehydrated air with an inert gas, such as argon, xenon or krypton within the unit. Argon, which has 34% lower thermal conductivity than air, is the most commonly used. Although argon-filled units cost around 5% more than air-filled units, they can improve a double glazing window’s U-value or energy rating by over 30%. Argon fillings should last the lifetime of a double glazing window and over a period of 25 years should not lose more than 5%.

Which begs the question – Why do the local window suppliers do it. Use air I mean it can only be because they make more profit.

If you are buying windows in Portugal ask the supplier to give you a written assurance that an inert gas has been used to fill the glazing panels.

About Castelo Construction Lda

Castelo Construction Lda are builders in Central Portugal. If you need an English speaking builder for renovation or new build work we will provide free estimates and carry out your work to a very high standard. Central Portugal builders, Central Portugal construction. New Construction and Refurbishment of Portuguese Property Its exciting for both our team and of course our clients to mark out on the earth the site of a new home. We will have been with them during the design process and have spoken to the architect many times so we will be comfortable with what we are about to do. For many clients this stage is a little daunting as it’s hard to see without experience just where the house is going to be in relation to other things on the property. Once the foundations are dug out the house normally looks smaller that they thought, As the pillars and foundation wall start to go you get a much better idea of scale. You can see with your mind’s eye the location of the kitchen, bedrooms and so on. Once the walls are up and the first floor is in place the rooms start to looks smaller again (something to do with the light absorbing properties of the bricks) once the walls are plastered the rooms look a lot larger and it starts to feel more like the home our clients imagined building. Many of our clients are not in the country full time so rely on our regular photographic updates and written reports. They are always surprised when they make inspection visits. As the build progresses we are involved with many specialist sub contractors and it is our job the get them on site at the right time so that the trades do not overlap and time is not wasted. Once the roof is on and tiled it is traditional in this area to have a dinner on site. Everyone who is involved in the build is invited to share a suckling pig dinner with local bread, oranges and of course wine. This is a great way for the clients to enjoy some local hospitality and meet the craftsmen who are building their new home. We also invite the near neighbors so that they get a chance to see what’s going on (when the house is at a very basic stage) and it gives our clients a relaxed opportunity to make their acquaintance. As we always accompany our clients to choose, kitchens, tiles, bathroom fittings or whatever they want. We can help with translation and of course negotiation! As the house is coming to completion we always have them professionally cleaned so that when we hand over the keys it feels more like a home than a building site. 2 months after the house is finished we are back to check for any small faults that may need attention and of course we are available to help and advise should that be needed.