"The Natural Philosopher" wrote in message
t...
wrote:

Seems to be some confusion about "thermal mass" - the only point in
using your masonry as a heat store would be if you have a source of
cheap/free heat which otherwise would be wasted such as a solar heat
set up.

You have. In one room in our house - the most glazed room of all on the
south side, the temperature rise is such that, unheated, it sits about 5-8
degrees above ambient on a sunny day. Its got massive brick chimeny in it,
and a massive solid concrete floor...after dark, it stays warm...

Temerature rise due to solar heating is enough to be factored into the
overall energy requieremenst of the building code.

High thremal mass evens out the diurnal range of temperatures en****ered -
unhteated, this equates to the average between day and night temperures.
In our temperate climate, this is arguably a very efficient thing - cool
by day, warm by night relatively..

Where it falls down is when teh house is unnocuyppied in te day in winter,
and allowed to cool dramatically. The extra heat required to bring it up
to temperature may negate any gains due to storage of solar energy during
te day.

In scandinavia, the requiremenst are such that its irrelevant anyway, as
teh houses there riun 24x7 heating in winter, and maintain constant
temeperatures - because the peak loads on getting an icy house up to temp
anyway are too severe.

Surprisingly in this case, for the UK climate, I am with Drivel as well.

I have one section of the house that is very low thermal mass, and its
noticeanbly less comfortable in summer and winter than the rest - its
never at the RIGHT temperature...

..and there is the issue of having high thermal capacity houses run at
24x7 heating...this certainly reduces the need for a high peak output
boler, which can save money. IO don';t know whether a 10% duty cycle on a
100KW boiler ins more or less efficient than a 100% on on a 10KW
one...whih is prettty much what I have in -7 deg C mornings. the old
boiler fires up, and stays up for several hours...more or less..


-
If you are paying for gas electricity etc you don't want to
waste it heating up the walls even if they are insulated outside. Much
better to have high insulation within the building and only heat the
minimum necessary

I think that this is the approach common in *very* cold countries such as
Sweden and Finland. Many houses use 30cm of insulation and triple
glazing. They recycle the heat in the air using a heat exchanger to warm the
incoming cold air needed to keep the interior fresh. Some years back, but
I remember seeing a video/programme about a house where only a few
hundred watts was needed to maintain the interior temp at 22C with
outside temps at about -10. Often only body heat was needed.

Obviously this is way over the top for the UK (until the Gulf Stream
switches off of course) but it shows that good interior insulation is
a good solution if you can afford the loss of inside dimension. As I
said earlier I used this approach. I lost the thickness of two interior
block walls and cavities off my rooms. There were other reasons.
The new walls carry the loads so relieving the old outside ones that
are up to 230 years old. However it has been very effective. I use
about 4000 litres of oil for a large and generously heated house and
hot water with a sizable family.

Peter Scott