The owner wasn’t worried. He had a château in France with similar artifacts, and all he had been doing to increase the moisture in the air was to have the housekeeper put pots of boiling water on radiators throughout the château.
For the 1898 house, we recommended a more efficient and unobtrusive system. We were able to come up with a design utilizing steam humidifiers to provide humidification automatically, around the clock. Our design put steam humidifiers in closets, in the basement, and in decorative brass grills in the occupied spaces.
Humidification will keep the level of water vapor in the air of your house at a level that’s comfortable for both you and the furnishings around you. Fortunately, the level that’s pleasant for you is likely to be close to a setting that’s reasonably good for your furniture and precious objects.
Humidifiers regulate the air’s relative humidity—the percentage of water vapor in the air relative to total saturation. What’s ideal? Each person has his own humidity-comfort level; during the heating season, that generally ranges between 30 percent and 40 percent. (Electronic equipment can be damaged by the static electricity that’s triggered when the air is too dry; a good level for electronics is 45 to 55 percent.)
Finding the right level for both human beings and the cultural material they cherish, such as works of art, photographs, and the family documents they want to preserve, is always a compromise, notes Paul Messier, a conservator of photographic materials in Boston (www.paulmessier.com), who is on the board of the American Institute for Conservation of Historic and Artistic Works. “What’s most important is maintaining a consistent setting. Keeping the relative humidity at a point between 30 and 50 percent, with very little daily or seasonal fluctuation, strikes a reasonable compromise between what’s comfortable for human beings and what’s ideal for their collections.”
Steam humidification is the system of choice for owners of high-end residences. Long used in the commercial market—especially in computer rooms, hospital rooms, and operating rooms—steam-humidification technology has, over the past decade, become economical enough for use in the residential market. It is more efficient (quicker to reach the desired moisture level) and more reliable (better at staying at the desired moisture level) than the older, more prevalent, less expensive system—the forced-air system with automatic bypass. Steam humidifiers, which can be installed in any residence (even a home that’s centuries old) are mini-boilers about 2 feet high by 1 foot wide and 1 foot deep. They can be mounted on a wall and piped into the existing duct system or mounted in a remote location within the house.
You’ll need an annual maintenance call from the firm that installed your humidifier—to clean out your entire steam-humidification system and remove the calcium from its drum, or to clean the drains and the special pad used in the automatic-bypass system. If your humidification system has worked the way it should during the year, it will have done its considerable part to keep you and your family comfortable and your treasures undamaged.
Kevin P. Carpenter is the owner of C & C Service, a family-owned and operated business that delivers administration, coordination, design/specification, installation, operation, troubleshooting, and repair of Heating and Air Conditioning (HVAC) systems. Kevin can be reached at 203.323.2866. www.ccservicellc.com.