Self-storage builders tend to install climate control as though people are going to reside in their units rather than store objects that are far less cold or heat sensitive. HVAC contractors further the problem by over-designing air conditioning and setting it for human comfort. All the while, little thought is given to humidity and moisture control.
In reality, controlling humidity, mold or mildew is more important than previously thought. When temperatures are set for 72 degrees, air-conditioning units cycle on and off with little effect on humidity. The short cycling is costly and should be avoided. Instead, run your air conditioning continuously to lower the humidity by 60 or 65 percent—an ideal range for self-storage.
Climate Control History
Climate control was initiated by large operators who converted urban obsolete buildings with existing heating and cooling systems into self-storage. New York had Edison Parking; Chicago had Public Storage; Seattle had Shurgard; New Orleans had Safeguard; and Houston had Pilgrim Self Storage.
These companies took a risk the market would accept a new type of storage. In many cities, no conventional storage was available, so people in need of it were often cornered into climate control. One unanticipated advantage of climate control was it offered excellent security in buildings with few entrances. The South was especially accepting of this new storage option.
Another advantage was properties were often closer to residential areas, and developers soon recognized customers most often stored at locations convenient to their homes or businesses.
Air conditioning helped prevent humidity with its resulting mold, mildew and deterioration. It also protected stored objects from dust and dirt. Again, this was an advantage of using buildings with fewer entrances, which prevented dust and dirt from coming in every time doors were opened. Fewer entrances also discouraged bugs, spiders and rodents from gaining access to the units.
Generally, climate control keeps temperatures below 90 degrees in summer and above 40 degrees in the winter. Humidity is kept below 60 percent to prevent mold and mildew. It’s a myth you should maintain 68 to 72 degrees winter and summer. It’s not only unnecessary, it’s costly. Instead, when summer temperatures soar beyond 90 degrees and 90 percent humidity, a storage facility that hovers at 80 degrees with 60 percent humidity feels quite comfortable.
Another myth deals with the size of air-conditioning units. For homes or offices, 450 to 600 square feet per ton of air conditioning is considered desirable, but self-storage requires 1,250 to 1,600 square feet per ton.
Facility owner Leon Chastant, of Lafayette, La., has been very successful in saving money on initial and operational costs by using 1,750 to 2,000 square feet per ton to cool his building, which is undoubtedly in a hot, humid area. So far, there’s no complaints.
As a building is filled with tenants’ goods, the cubic feet of free air space is reduced significantly, creating less of a draw on the air-conditioning system. Under-designing and eliminating short cycling lowers humidity to acceptable levels, saves on operating costs and lengthens the system’s lifespan.
Several years ago, a New Orleans operator asked me to visit his property. He was thinking of adding more air conditioning because he couldn’t get the humidity low enough. Since he was cooling to 72 degrees all he had to do was raise his thermostat to 78 degrees and the problem took care of itself. Another Louisiana operator, who runs five properties, told me he used 100 tons in everything he built. He was wasting $60,000 in each property on excess air-conditioning units.
There is little concern about heating since most storage units have electrical strips. In the North, dual systems that heat with natural gas are common. Large buildings with one entrance have an advantage when it comes to keeping the doorway clear and the facility heated. Still, many tenants avoid entering storage facilities when there’s snow and ice in the driveways.
When visiting 11 facilities during the winter in Madison, Wis., I noticed only one had people entering the property because of the 3-inch snow pack. It was the only site with climate control and it was continuing to do a brisk business.
Zoning departments tend to overestimate daily use and require far more parking spaces at climate-controlled buildings than necessary. Studies indicate a traffic flow of 8.1 cars per day for every 100 units, with a national average of 20.8 cars per day per facility. Knowing properties are open an average of nine hours a daily, this means maybe one to two cars an hour per facility. Many municipalities require parking for five to 10 times the needed amount. As time passes, parking requirements may ease as building departments become more educated.
As land costs continue to escalate, more owners are building multistory buildings. Two-story sites allow the air-conditioning load to be evenly divided between the first and second floor. A lot of heat comes through the first-floor during warm months, and the second floor gains heat from the roof. These tend to balance out, but the second floor may need a little more air conditioning. When building three or more stories, the middle floors require 25 percent less air conditioning because the cooled air spreads through several floors of the building. A competent contractor can design the building with appropriate air conditioning loads per floor.
Don’t skimp on insulation. Saving a few dollars on inadequate insulation will be lost to the added cost of increased air conditioning. Use a minimum of 6 inches of fiberglass (R 19) for roofs and walls. The building’s heat loss and gain must be determined by the HVAC contractor, who will calculate insulation values, ceiling heights, cubic area, type of construction, amount of lighting, exterior doors, number of windows and the air infiltration from outside.
Do your homework and research the efficiencies of heating and cooling units to determine what best suits your site. Lower-priced units with higher operational costs and less efficiency is one option. Another is to pick high-efficiency units that will cost less to operate and save money over the years.
Coastal areas and areas of the Northeast or West may not have high temperatures but need a dehumidification device. Traditional box-unit dehumidifiers don’t lower humidity levels evenly throughout the building. The HVAC system should have a separate humidistat controlling the operation of reducing humidity. On high-efficiency units, a circulating fan should run continuously to circulate the air throughout the entire building.
Contrary to previous thought, HVAC ductwork isn’t required in hallways with vents ducting into each unit. Just keep partition heights between 12 and 20 inches below the ceiling to circulate between units. The humidistat will remove moisture and re-circulate dry air.
To meet today’s demand, many large multi-property owners are building nearly 100 percent climate-controlled properties. With rising land costs, some are adding up 12 floors. Climate control demands higher rents and can justify increased construction costs. Some multistory facilities are designed to look like office buildings, making them easier to gain code approvals.
Climate control and dehumidification should always be mentioned in advertising. Always ask new tenants, “Are you planning to store anything of value?” and then advise what units might be best.
Climate control benefits customers by keeping their belongings in the same condition as when they were first stored, free of mold and mildew. For this, tenants typically pay 15 to 35 percent or more than conventional units. While costs for building climate control storage are 20 percent higher than conventional storage, operating HVAC systems is seldom more than 2.5 cents per square foot per month, making climate control a good revenue-generator for self-storage. Don’t wait to join in the profits: Take control of your climate now.
Dan Curtis is president of Atlanta-based Storage Consulting & Marketing, which provides feasibility and marketing studies to potential self-storage owners. He is a frequent contributor to Inside Self-Storage as well as a speaker at numerous industry conferences. For more information, call 404.427.9559.