IMM wrote:

"Terry" wrote in message
. ..

Another problem that can arise with very high levels of insulation and a
well sealed house, is large amounts of condensation.
In Scandinavian new builds I've seen this has been specially catered

for.


Well, sort of. But ..............
Here in Canada with longer colder winters (and often heat leaching winds!)
higher values of the insulation reduce heat loss and therefore the cost of
heating ones home. Since the energy cost increases of the 1970/80s etc.

much

thicker insulation has been the 'standard'. Most wood frame houses now

have

6 inch wooden stud outer walls filled with insulation and/or sheeted with
foam boards, older homes 4 inch.
But it is the 'vapour barrier' on the warm side of the insulation,

whatever

type and thickness it is, that is important. It prevents the warm air from
seeping out into the outer walls and ceilings. Warm air is moist; when it
cools down the moisture in it condenses into water and can cause rot,

mould,

damp/wet insulation and even condensation and water droplets in the attic.


It also makes the house air-tight reducing much heat loss in winter, and
gain in the summer. The Canadians have the R2000 standard, which is one the
most advanced in the world, if not the most. The Canadians, say "build
tight, ventilate right".

Yes, but the whole point that you ALWAYS fail to realise is that cost
benefit analyse comes up with different answers for different climates.

In the Mediterranean and indeed in most tropical places, its well known
that insulation is pretty useless unless you also install air
conditioning, and its better to rely simply on shade (overhanging eaves)
and a lot of mass to average out diurnal temperature variations.

Mediterranean houses seem to have rooves of triple layers of tiles
cemented together, and concrete without insulation at all is the
preferred wall material - or simple blockwork. Timber house get
insufferably hot.

Yet in scandinavia, timer with massive insulation is the simple cheap
way to achieve warmth in winter.

One size fits all is your mentality John, and its an ideological
disaster everywhere its been applied.