Open Forum

A question for museum colleagues across collections, conservation, facilities, and leadership:

How does your institution decide what temperature and relative humidity conditions are appropriate for each collection space?

Preventive conservation is the practice of identifying and managing risks before they cause damage to collections. Temperature and relative humidity are two important "agents of deterioration," but managing them is more complex than selecting a single temperature and RH target for the entire museum.

For example:

1. Do you know your institution's approved temperature and relative humidity ranges?
2. Do you know the permitted rate of change within those ranges?
3. How do you account for the unique characteristics of each space, such as the thermal mass of its walls, floors, and ceilings?
4. How do you consider the different ways that paintings, paper, wood, textiles, metals, photographs, and other materials respond to environmental change?
5. And perhaps most importantly: who makes these decisions, and how do the conservation, collections, facilities, and building-operations teams collaborate?

All these variables make for a complex equation! A universal target such as 70°F and 50% RH may appear simple, but it is not necessarily the best preservation strategy for every collection or every space. Maintaining one rigid setpoint everywhere can also require significant HVAC energy and operating cost.

I would love to hear how your museum approaches these decisions. Are your environmental policies tailored by space, zone, or collection type? What information or tools do the different teams use, and how is building-system data turned into something clear and useful for conservators and collections staff?