For a variety of reasons, low first cost considerations and low fuel cost at the time of building design among them, encouraged least cost HVAC equipment solutions with integral line-voltage thermostat control. Poor temperature control and lack of programmable temperature setback capability is in fact synonymous with a variety of widely used HVAC equipment types. For example, electric baseboard strip heat, window and wall a/c, packaged terminal air conditioning (PTAC), packaged terminal heat pump (PTHP), fan coil units (FCU) and others typically do not have precision thermostats or programmable capability. Instead, users fight with integrated line-voltage thermostats. Such controls are imprecise by design, improperly located, difficult to regulate, and generally a nuisance to adjust, often resulting in their being set and left in a relatively high demand for heating or cooling. In fact, some heating and cooling equipment have no thermostat control at all, only a fan speed switch! Which means someone has to turn it on when they're uncomfortable and turn it off again when they're uncomfortable in the other direction...

ENERNET Corporation's patented T9000 wireless thermostat is the most flexible thermostat solution on the market today. The T9000 is a two-piece system designed to provide precision temperature control without the installation difficulties and expense of wiring. Battery operated, it uses the unlicensed 900MHz RF band to communicate with one or more control nodes. Control nodes are installed at the heating and cooling equipment being controlled, and the thermostat is simply mounted on the wall with no need to wire it to power or the equipment under control.