“The space renovations included the installation of two new rooftop air-handling units (AHUs) with DX [direct exchange] A/C and natural gas heat exchangers. That first season change from summer to fall, our staff was overwhelmed with requests to adjust the space temperatures. In the morning when it was cool outdoors, we would receive calls to raise the temp and then in the afternoon when the outdoor temp would rise, we would receive calls to lower the space temp.

“We had checked the operation of the control system and found everything to be in working condition,” Langless wrote, “and had made program changes to alleviate the problems. Even though we were sure our system was working as it should and maintaining space temps to within 1 degree to 2 degrees, we could never completely satisfy the occupants of the space. We mounted a ‘dummy stat’ adjacent to the ‘controlling stat’ and gave the floor manager the key to the stat — now the occupants could ‘control’ their space as they desired with the permission of their manager.

“The dummy stat did nothing except to give the occupants the impression that they had control of the HVAC system,” Langless wrote, “and the psychological effect of having control of their work environment. Our service calls disappeared, and to my knowledge, that system is still set up and working as it has since 1987.”

Tell The Decisionmaker

“The owner of the building needs to be made aware of it,” agreed John Sartain, White Rodgers’ Market Manager — Thermostats.

Sartain said that he knew of cases where nonfunctional thermostats were installed to protect the equipment, and the temperature was “repeatedly being adjusted up and/or down” by building occupants having “thermostat wars” (cases where one occupant is too hot, then the other is too cold, and thermostats are raised and lowered all day). “You can end up damaging the equipment due to short starts” and related problems, he said.

In other cases, thermostats installed in high-traffic areas were subjected to some pretty appalling abuse, including burning with cigarette lighters. “We serviced a lot of canteens,” Sartain said. “In some of those applications, thermostats were brutalized.”

When a nonfunctional thermostat was installed, “The manager of the canteen knew where and how to control a functioning thermostat,” Sartain said. Newer products with remote sensors allow control of the dining room from a remote location, he added.

“In a canteen or restaurant application, the goal is providing customer comfort via controlling temperature in the public area,” Sartain explained. In these public areas, a thermostat guard “by its very presence makes thermostats vulnerable to tampering. Most people can identify a thermostat or a thermostat enclosed in an opaque or metal guard. So a secondary goal in some applications is to keep the public and others from ‘playing’ with the setting and possibly causing discomfort or equipment damage.”

By using a remote sensor, “the thermostat itself can be positioned in a more secure location, like the manager’s office. Our Comfort-Set 90 Series products offer remote sensor capability. The single-stage models can use one remote sensor, and the multistage models can use up to three remote sensors, plus the local sensor within the thermostat. A weighted average allows the contractor to give more priority to different sensors throughout the day.”

Other thermostat manufacturers, such as Honeywell, also offer sensor-based systems with a variety of interfaces. For example, in commercial buildings over 50,000 square feet, “Various parts of a building would have a sensor on the wall wired into the central controller. These … sensors are usually the shape of a large matchbox with a stainless steel or white plastic cover.

“In some cases,” the company explains, “the temperature can be adjusted locally; however, it depends on how the system is configured. … Typically in situations where temperature control is ‘distributed’ and not local, an occupant would call the building manager to have the temperature adjusted.”

Mechanical system protection is a big reason for the installation of nonfunctional thermostats. “As a service tech years ago, I have used them in a visiting room,” said Ted Klosterman of Bellevue, Ky. “We had a big problem with persons wanting to play with the stat lock boxes — I made a duct stat out of two temp controls and when I was done, all the room stat did was tell you the temp in the room.

“This was more for the good of the unit than anything. We always had to clear the coil of ice when someone would turn the stat to 50 degrees; it also saved on compressor replacement. Before I did this, we lost two compressors; no compressors were lost that summer due to too many hands on the stat.

“The funny thing was, they would mess with the stat and think it was doing something; as long as they could play, they were happy,” wrote Klosterman. “Funny how things work.”

According to research from Johnson Controls, “Numerous studies show that investing in the indoor environment can be justified on the basis of productivity improvements alone.” The company’s solution is its Personal Environments® workstations, at which a desktop control unit gives the desk occupant the ability to adjust temperature, lighting, airflow, and acoustics.

“Improvement to the workplace environment is a highly cost-effective way of enhancing employee satisfaction, productivity, and the company bottom line. According to two researchers, the ratio of building operation costs to average salary costs is 1:13. A company would have to eliminate more than a month’s worth of building operating costs to pay for just two days of lost worker productivity.”

Check The Equipment

Int-Hout said that at one jobsite, he removed the locked covers, then held a thermostat class for building occupants. It included information on “Here’s the guy to call” with comfort complaints.

Also, in cases where it seems that all females are complaining, perhaps service contractors should look for signs of air stratification. If air diffusers are not selected, installed, or maintained properly, it could result in colder air at the foot/ankle level than at the neck level: vertical temperature stratification. In these cases, women complain, men don’t. This happens because women are more likely to wear nylons than heavier socks, Int-Hout pointed out.

According to Int-Hout, placebo stats can indicate a system problem. “If it’s cold at the floor level, take an $18 Radio Shack indoor-outdoor thermometer; set it on a desk, and dangle the bulb to the floor level.” If the measurements detect stratification, repairs probably would involve rebalancing the system, Int-Hout said.

Placebo thermostats can sometimes solve chronic complainers, he said. However, “Sooner or later they figure it out. We need to make sure equipment is working properly.”

Doug Huberty in St. Paul said it nicely: “If you fix the problems causing the too-hot, too-cold complaints, the staff forgets there is a thermostat on the wall.”

Publication date: 03/31/2003