Climate Control: It’s Not the Heat, It’s the Humidity

Have you ever put a newspaper by a window and left it there for a few months? When you finally remembered it was there did you notice how faded and bent it had become? Storing items such as clothing and paper in traditional self storage units that are exposed to hot and cold weather is becoming less and less the norm in the industry. These days, people want to protect their valuables. After all, finding great-grandmother’s wedding dress falling apart is not what any self storage customer wants to experience.

Enter climate-controlled self storage buildings, which kicked into a higher gear in self storage 10 years ago and have been gaining momentum ever since. Self storage facilities charge customers extra money to rent climate-controlled units and normally find a waiting line of customers who want to use them. Some facilities even have climate control to keep bottles of wine at the perfect temperature.

Climate control is certainly worth the time and effort, but lately, studies have indicated that it is less and less about keeping a constant temperature and more about controlling the humidity. In fact, the use of air conditioning or heat only has, in recent years, earned the moniker “temperature control” because it does not address humidity at all.

Any humidity reading above 60 percent allows rust, mites, mold, paper rot, wood degradation and mildew to evolve. In the past (and the early days of self storage) facilities relied on air-conditioning systems to dry the air. As it turns out, high temperatures don’t always coincide with high humidity. High humidity is actually more likely to occur at night, while high temperatures obviously occur more in the daytime, especially the afternoon.1.

According to Tim Dietz, president and CEO of the Self Storage Association, the optimum relative humidity for a self storage unit is around 55 percent.2. Having a relative humidity of 50 percent or slightly lower on a full-time basis will work just fine. Combine that with cooler temperatures in the summer months and some heat in the winter months and you essentially have true “climate control.”

If you are interested in having a true climate-control system, you will have to find heating and air conditioning companies that are knowledgeable about humidity and can provide humidifiers that work effectively in your entire climate-controlled area.

The cost of renting self-storage with climate control varies widely—anywhere from 20 percent to 50 percent higher than traditional storage, according to Tom Maxfield, national operations director at Move It Storage Management in Dallas.3.. Maxfield also says that the extra cost of climate control—often referred to as the “climate control premium”—typically adds from 35 percent to 50 percent. A basic 10×10 storage unit with climate control might cost $140 a month to rent while a unit without climate control could cost $90. These are generalizations and individual self storage facilities’ prices vary according to the owner’s determinations.

Self storage climate control is in high demand, which explains the ability to charge extra for it. But make sure you are offering true climate control and not temperature control. If a client’s great-grandmother’s wedding dress is breaking down in a unit purported to be “climate-controlled,” you will have trouble on your hands for false advertising.


1. Inside Self-Storage (Dry-Air Storage: Managing Humidity in Self-Storage Facilities — August 28, 2009)

2. “Do You Need Climate Control in Your Storage Unit?” –

3. “Do You Need Climate Control in Your Storage Unit?” –