Hi,  D. L. Bullock made some excellent points regarding the humidity
requirements of musical instruments [051225 MMDigest], and I agree
with everything he said.  It is vital to have an accurate hygrometer
(humidity gauge) in the music room, and to provide humidification of
some kind.  In my experience, in centrally heated rooms in winter the
humidity can drop alarmingly, sometimes down to almost single figures.

Last year we moved a collection of automatic instruments, including
about ten pianos, from England to British Columbia, Canada.  Amongst
things to consider prior to the move was the conditions that the
instruments would be subjected to in transit.  The route was via
London docks to Montreal via the St Lawrence seaway, and thence by rail
across Canada to Vancouver.  That involved travelling right across the
Canadian prairies, which in winter can reach temperature lows of -40 C.
and of necessity therefore, almost zero humidity.  The instruments were
well wrapped in waterproof paper and crated, but you can't seal them
completely.  We shipped in the autumn, the instruments arriving in B.C.
in November, thus missing the extremes.

Europe seems to be somewhat more humid than the North American
continent, and it is my experience that 30% RH is too low for British
pianos.  We maintain our hall at 55% with the aid of a commercial
atomising humidifier, model SF24 from Walton Labs of New Jersey,
http://www.waltonlabs.com/SF-24.html

The humidifier is plumbed into the main water supply and has an
adjustable humidistat that maintains the setting within about 2% RH
either side.  In freezing conditions it is frequently on for 20 minutes
every two hours, blasting a small rain cloud across the building, and
using several gallons of water each time.  It brings home to you how
much moisture is actually needed to maintain 55% in a heated building!

An antique dealer here in B.C. told me he never buys British pianos
because they nearly always have cracked soundboards, whereas American
and Canadian made pianos don't.  Lack of humidity is the reason, of
course.

Regards from Revelstoke, British Columbia.
David Evans