Most commercial buildings use some form of time of day control for the heating and cooling systems. Larger buildings are often equipped with centralized building management systems (BMS); however, the vast majority of buildings that are not large enough to justify these often costly systems must rely upon programmable thermostats.
Programmable Thermostats come with a very wide variety of features, ease-of-use and functionality. Their price range varies, starting anywhere from $20 for a simple unit to $300 for “fully loaded” models. Almost all of them are able to accept unique programs for each day of the week. Some thermostats even allow for extraordinary events such as holidays.
The newest generation of programmable thermostats are called “smart thermostats” and include features such as electric meter communicability, remote access control via a computer or cell phone, and in some cases they may even learn and adapt to occupancy profiles. Although growing in popularity, smart thermostats represent only a very small fraction of the installed base in commercial buildings. Many of the more popular ones still have somewhat limited applicability to commercial HVAC systems.
So what’s the problem with programmable thermostats? It’s basically this: rarely are they properly programmed or fully utilized. Almost universally, their utilization isn’t optimized. There are a variety of reasons for this, so let’s explore a few.
If you have ever had teenagers living in your house, you know how maddening it can be to find lights illuminating an empty room, doors ajar, computers and televisions left on and even windows open while your heater or air conditioner is running. This isn’t because they are bad people; it’s just that the month’s utility bill doesn’t come from their allowance.
The same problems usually exist in commercial buildings. The occupants most directly affected by the HVAC systems don’t see them, and are very rarely the ones to pay the bills. Those of us who are “comfort professionals” can attest that there are many varying opinions as to what the “right” temperature is.
We certainly all have seen this: an occupant sneaks by the thermostat, cranking the temperature up to where only inhabitants near the equator might find it comfortable. A few minutes later, another staggers over, and before mass dehydration sets in, drops the temperature to where the windows begin to frost.
This causes building owners and managers to resort to imprison thermostats in silly looking cages, which often exacerbates the frustration that occupants feel over their comfort control. Some occupants become very creative, and find clever ways to trick and open these thermostat covers, or trick the thermostat’s thermometer. So, at minimum, there is often a conflict between the interests of the occupants, and those who foot the bill.
Let’s examine another major—yet simple—reason why programmable thermostats don’t work well to save energy: the person with the vested interest in the energy costs isn’t the one programming the thermostats. Well-intentioned owners, managers and maintenance staff usually will input a basic program at the time of installation, but rarely is there someone to regularly review these programs, which is necessary to tweak them to reflect the current schedule and usage of the building. As the saying goes, “out of sight out of mind.”
Unfortunately, many programmable controls aren’t intuitive to use, let alone program. Documentation gets misplaced, and the previously trained operators forget, get transferred, or simply aren’t available. Service providers typically don’t have access to the key person who can make decide on the necessary programming parameters of daily, weekly and annual schedules, let alone what the “appropriate” temperature levels are.
It’s extraordinarily uncomfortable for the service provider and or installer, to be asked to install a “dummy thermostat.” Simply, these are thermostats that are placed for the occupants to fiddle with, yet don’t control anything except, often their perceptions. Thankfully we very rarely get these requests.
Some of the newest smart thermostats are relatively inexpensive and accept basic time-of-day programming, yet will automatically reduce HVAC system operation when there is no activity observed. We call these occupancy based smart thermostats. They allow the occupant to easily adjust the temperature and override a setback program (i.e. working late or on weekends) while still allowing the building manager to pre-program set point limits to reasonable levels. They can be networked via innovative wireless networks, have remote accessibility, can be connected to the HVAC unit with wireless connections, track energy utilization and consumption, and even look attractive.
A lack of maintenance, faulty installation and poor designs are often the cause of discomfort within a building. Thorough and comprehensive maintenance will identify and eliminate many of these maladies, but the newest generations of occupancy-based smart thermostats are useful tools in minimizing wasteful operation and delivering optimal occupant comfort. Most of them compile and display information about current and historical usage enabling owners and occupants to make more informed decisions about system usage. Allegedly it was this type of occupant activity and usage that attracted Google to recently buy Nest for a whopping $3.2 Billion.
The bottom line;
- buy a programmable thermostat (preferable a smart one)
- program it properly
- update the program whenever necessary
- check the thermostat settings regularly (in case someone plays with it)