Abstract: A method and control apparatus are described for limiting peak-load contribution by HVAC systems and other systems, and for measuring the effect of energy-conservation expedients. The control apparatus reduces the percentage of on-time and thus fuel and power consumption and demand for utility capacity to a predetermined extent during peak-load periods, by inhibiting fuel-on signals from the thermostat of each HVAC system to the furnace, fuel-pump, or air conditioner of the HVAC system, or other system, so that the total on-time during a load-measuring interval is reduced to a predetermined amount. During non-peak periods, the control apparatus is inactive and the thermostat controls the HVAC system. The measurement aspect of the invention measures and records on and off state time intervals for the HVAC system, and temperatures associated with such intervals.

Abstract: A thermostat is disclosed for controlling a heating system, particularly a forced hot-air furnace, so as to improve fuel efficiency and decrease peak fuel load. The thermostat controls the length of fuel-on cycles, so that the heat exchanger of the furnace is not saturated. A wide deadband (approximately 3.degree. F.) for the thermostat further aids in lessening fuel usage. Forced air operation continues for a secondary-delivery period immediately after the thermostat turns the furnace off, thereby extracting additional heat from the heat exchanger and ductwork, but the length of the secondary-delivery period is limited so that the heat exchanger does not cool off beyond a predetermined amount.

Abstract: An interactive electronic thermostat operates to communicate with an installer through an audible or visual display and keypad to instruct the installer to perform tasks and enter observations to effect proper connections at the thermostat of heater/air conditioner wires in spite of the absence of labels identifying the functions of those wires. The thermostat requires entry of coded indicia representing operator-observed conditions in the system in response to displayed instructions carried out by the operator. Control circuits are automatically assigned functional tasks in response to the operator-observed conditions entered into the system. Different program routines are invoked depending upon the number of system wires and the type of heater/air conditioner being controlled. Under appropriate circumstances, messages are displayed informing the operator/homeowner that the thermostat is incompatible, or has no advantageous use, with the heater/air conditioner.

Abstract: An interactive electronic thermostat operates to communicate with an installed through an audible or visual display and keypad to instruct the installer to perform tasks and enter observations to effect proper connections at the thermostat of heater/air conditioner wires in spite of the absence of labels identifying the functions of those wires. The thermostat requires entry of coded indicia representing operator-observed conditions in the system in response to displayed instructions carried out by the operator. Control circuits are automatically assigned functional tasks in response to the operator-observed conditions entered into the system. Different program routines are invoked depending upon the number of system wires and the type of heater/air conditioner being controlled. Under appropriate circumstances, messages are displayed informing the operator/homeowner that the thermostat is incompatible, or has no advantageous use, with the heater/air conditioner.

Abstract: Environmental heating/cooling systems are controlled by an interactive microprocessor and have continuous on-time and adaptive cycling modes wherein continuous on-time brings the temperature to a programmed set point and cycling precisely maintains that temperature rather than causing the temperature to oscillate between limits of a dead zone. Minimum pause and on-time intervals of the cycling mode are established in accordance with optimum thermal transfer efficiency and/or equipment limitations. The initial cycle pause interval is a function of the degree transition time (i.e., time required for system to change temperature one degree as measured during continuous on-time mode); the initial cycle on-time interval becomes the established minimum interval. Cycle intervals are modified as necessary to maintain the temperature at the set point with preference given to minimizing the cycle on-time interval.