Monthly Archives: June 2015

Can new windows reduce road noise?


I was recently asked if new windows reduce road noise and if so, by how much. The answer is simple yes but everything depends upon the amount of noise reduction that’s being requested.

How is Road Noise Measured?

Noise is measured in decibels (db’s). In general terms noise is deadened the further apart the two sheets of glass are apart, that’s why secondary glazing (spaced 200mm) offers maximum reduction however most home owners are driven to do something with their primary windows and expect the double glazed sealed unit to do the same job.

Fitting two sheets (or triple) in the main windows will reduce sound, but you’ll get more reduction fitting two sheets of different thicknesses (4mm and 6mm) because noise reverberates and sets of the second sheet (if it’s the same thickness). Homeowners should also consider 6.8mm “Stadip silence” a sound deadening laminated glass used in libraries as one of the sheets.

Most noise passes through trickle vents very easily regardless of frame material timber, PVC aluminium etc, and preventing dirt and noise to pass through is extremely difficult unless you have a monstrous size of trickle vent. Many installers fit them thinking they are needed, if you current windows don’t have them, the regs say your new windows don’t need them either (normal house no special gas ventilation etc)

I suspect wooden frames, being solid will be less noisy than PVC frames which tend to be hollow unless they are foam filled.

So in summary, it is better to have two thicknesses of glass or two sheets wide apart like secondary glazing.

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How to stay cool this summer


Now that summer has arrived, although it feels like autumn, you will soon face those balmy nights wishing you knew how to stay cool this summer.

Most homes have had some sort of double glazing fitted, much of it inappropriate because whilst it may be compliant with FENSA many styles of window fail to meet the air change per hour requirement of the building regulations.

Why is this important, well its the ease that air gets changed that determine the how stuffy a room is, how much moisture is trapped inside the room and how cool you will be.

What Is the Best Way to Stay Cool This Summer?

Without doubt, the best method of getting a cool breeze and free air conditioning, is to encourage natural convection of air. Everyone knows warm air rises, so cooler air will naturally fall to the floor, in turn helping push more warm air towards the ceiling. If you open windows at the top and bottom (like sash windows) then you’ll get a massive increase (called purge ventilation) over most other styles of window.

All new buildings need to demonstrate the windows will enable a minimum of 4 air changes per hour, the regulations for replacements states they should also comply, however it is incredibly difficult to measure air changes so this requirement is often overlooked.

Using sophisticated computer modelling, we have seen reports that suggest compliant windows like top or bottom half windows with fixed lights, only produce 2.8 air changes per hour, not 4.


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