On a trip to the in-laws yesterday, I noticed an obvious difference in
sound insulation between their house and a nearby newly-built house.
1950's brick construction with uPVC framed double-glazing units
installed about 5 years ago. The yappy dog perched in the window could
not be heard barking from outside the house.
Six months old, brick and block construction with, presumably the
latest spec, uPVC framed double-glazing. The yappy dog in the window
could be heard loud and clear, as if there was no window.
On the assumption that one yappy dog is probably as loud as the other,
I was surprised at the obvious difference in sound insulation.
Presumably the neighbours in the new house must also be able to easily
hear outside noises, whereas my in-laws are nicely insulated from the
My in-laws are notorious misers and I expect that they bought the
cheapest windows they could find.
I'm no expert on double-glazing but I would have expected a more
modern unit to offer at least the same level of sound insulation, if
Would it be fair to assume that if sound can travel easily from inside
to outside, so too can heat. This doesn't seem right - unless the new
windows are just cheap rubbish, of course.
Anyone care to offer any thoughts on this?
Sound insulation is compromised by even very small gaps. More modern
double glazing is required to have trickle vents on most (all?)
openings whereas older stuff wasn't and usually didn't. The sound
transmission from the modern one will depend heavily on whether the
owners had the vents open or not.
In-laws didn't pay extra for trickle vents? New windows probably have
them as compulsory (they aren't, actually, but many builders would use
them rather than any more sensible means of background ventilation)
Thus spake HVB ( email@example.com) unto the assembled multitudes:
Are you sure the in-laws' yappy dog wasn't miming? They do things like
that, y'know. Yappy dogs can't be trusted. ;-)
Seriously though, I have noticed quite a difference myself. My own house
is brick-built and double-glazed throughout and pretty well sound
insulated, but I've been in friends' new houses and you can sometimes hear
the neighbours changing their minds. They just don't build 'em like they
The gap for optimal sound insulation is, IIRC about 100mm. that is
too big for optimal heat insulation because you get circulating
currents between the panes. So, poorer sound insulation does not mean
poorer heat insulation, necessaorily.
For really good sound insulation I think you need three panes with
In article ,
Sound transmission through double glazing depends on two things
effectively - the thickness of the glass and the gap between the panes.
And for effective sound insulation you require a larger gap than is common
- and thicker glass.
I'd guess the older window had thicker glass.
Of course modern windows have trickle vents too which let through sound.