<html> Hmmm... maybe start with a good resettable hygrometer/thermometer which measures highs and lows (doesn't Schaff and Pianotek sell them? ;)  so the owner knows what they have to work with or against.    I carry one in my toolcase anyway, so my customers will know about humidity and how it affects their instruments Another idea would be to investigate replacing the windows in just that room with better sealing ones.  Windows... and fireplaces... are a major source of heat loss so it's a good idea to plug those holes, as well as putting insulation around electrical outlets underneath the switchplates.   None of this is new stuff... it just takes a trek down the home improvement aisles at Menard's or Home Depot for ideas in how to insulate and seal up a room... everything from heat-shrink film for windows, to expandable foam in a can, to deflectors for heating air ducts and specially cut switchplate liners. After the owner gets the "this old house" problems solved, it'll be time to discuss the addition of humidity control, whether it's a large room humidifier with a fan, or Dampp-Chaser systems, or several mason jars filled with water sitting next to the pedal trapwork (like I found last week in an old upright ;).  Marty Reyburn </html>