Diagnostic thermostat

DETAILED DESCRIPTION OF THE DRAWINGS The thermostat shown in the figures, particularly in FIG.
3, incorporates a microprocessor 6 which utilizes a digital display to show several pieces of information, selectable by the operator.
The unit also incorporates an electronic clock 7.
In addition to sensing inside temperature directly at the thermostat itself and controlling the heating system in the normal way, the thermostat senses outside temperature by virtue of an outside temperature probe 11 and wires 12 connecting the probe 11 to the thermostat shown in FIG.
3.
By accumulating degree days and run time of the heating or cooling plant, the thermostat can calculate, store and display energy used per degree day for a given period of elapsed time.
This information represents the performance or efficiency of the building and its heating system.
Naturally, any other units may also be employed.
For example, the thermostat could express the average building performance in BTUs per degree day over the previous two week period, two months, or even a year.
It could also express this information in terms of energy savings or in terms of a percent reduction from an initial standard energy consumption rate.
The data would be accumulated in the memory of the microprocessor, and displayed upon command on the digital display.
In FIG.
3, an indoor temperature sensor 8 is illustrated, along with a wiring terminal 9.
The wiring terminal 9 also allows the connection of the control wires 14 going to the furnace 10.
One important advantage of the diagnostic thermostat disclosed herein is that improvements in the building or its heating system would become immediately visible in terms of the building efficiency.
For example, improved sealing of doors and windows or building insulation would show up as an immediate improvement in building efficiency, i.
e.
less BTUs per degree day over a given period.
Similarly, a decrease in furnace efficiency, such as would occur with a clogged filter or combustion jet, would show up as a decrease in building efficiency, i