Short answer
Anything made of wood, paper, fabric, leather, film or electronics benefits from climate control, especially for long stays. Photos, documents, books, artwork, instruments, upholstered and wood furniture and media are the clearest cases. Metal tools, plastic and glass usually do fine in a standard unit.
The simple rule: if it’s organic (wood, paper, cotton, wool, leather) or delicate (film, electronics, paint), it reacts to heat and moisture. Those are the items that need climate control. Inert materials like glass, ceramics and plastic mostly don’t.
Items that need it
| Item | What goes wrong | Safe range, per preservation guidance |
|---|---|---|
| Paper and documents | Mold, yellowing, brittleness | Cool, about 35% RH, stable (Library of Congress) |
| Books | Mold, warped covers | 70°F or below, 30% to 55% RH (Library of Congress) |
| Photos | Fading, sticking, mold | 70°F or below, 30% to 50% RH (Library of Congress) |
| Clothing and textiles | Mold, brittle fibers | 65°F to 75°F, near 50% RH (National Park Service) |
| Paintings | Flaking, cracks, mold | 64°F to 75°F, 40% to 55% RH (National Park Service) |
| Records and tapes | Warping, mold, signal loss | 55°F to 70°F, 30% to 55% RH (National Archives) |
| Wood furniture | Splits, loose joints, mold | About 50% RH (National Park Service) |
| Leather | Mold, shrinking, cracking | 40% to 60% RH (National Park Service) |
Electronics and musical instruments belong on this list too. See the separate answers on electronics and pianos.
Why swings matter as much as extremes
Most guidance stresses stability. The National Park Service says repeated changes in temperature and humidity make paintings expand and contract, which “often leads to flaking paint.” For textiles, it warns that fluctuations cause stress that breaks weak yarns.
A standard unit swings with every heat wave and cold snap. That’s the main thing climate control buys you.
Instruments
Wood and metal instruments are both sensitive. A Brigham Young University conservation guide notes that woodwinds “are susceptible to changing humidity” and that metal instruments are prone to corrosion. Keep them in their cases, in a controlled unit.
Items that usually don’t need it
- Metal tools and hardware (keep them dry, though, to avoid rust)
- Plastic bins, plastic furniture and toys
- Glass and ceramic dishes
- Lawn and garden equipment
- Sporting goods without leather
- Holiday decorations made of plastic
Even these can suffer in a truly wet unit. Raise them off the floor and use lidded bins.
A packing tip that helps either way
The National Park Service advises never storing textiles in attics or basements, and the same logic applies to a damp unit. Store sensitive items off the floor, away from outside walls, and in breathable or archival containers rather than sealed plastic when humidity is uncertain.
If your list includes several items from the first table, look for verified climate-controlled storage near you. Large metros like Dallas have many options to compare.