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munication may in the form of a signal sent over the power
lines themselves, or a wireless communication over a data
network arranged by the utility. These meters allow utilities to
accomplish a number of goals, including offering pricing that
varies by time of day in order to encourage customers to move
consumption away from peak demand hours. These Smart
meters can cost hundreds of dollars, however, and require
both a “truck roll' a visit from a trained service person—
and most likely the scheduling of an appointment with the
occupants, because Swapping the meter will require turning
off power to the house.
If the utility installs a smart meter at each house that con
tracts to participate in a PDR program, it may be possible to
verify that the NC is in fact switched off. But this approach
requires two separate pieces of hardware, two separate com
munications systems, and the ability to match them for veri
fication purposes.
It would be desirable to have a system that could both
implement and verify residential peak demand reduction with
reduced expenses.
SUMMARY OF THE INVENTION
At least one embodiment of the invention that includes
system for predicting the rate of change in temperature inside
a structure comprising at least one thermostat located inside
the structure and controlling an HVAC system in said struc
ture; at least one remote processor that is in communication
with said thermostat; at least one database for storing data
reported by said thermostat; at least one processor that com
pares outside temperature at at least location and at least one
point in time to information reported to said remote processor
from said thermostat, and wherein said processor uses the
relationship between the inside temperature and the outside
temperature over time to derive a first prediction for the rate of
change in inside temperature assuming that the operating
status of the HVAC system is “on”; and said processor uses
the relationship between the inside temperature and the out
side temperature over time to derive a second prediction for
the rate of change in inside temperature assuming that the
operating status of the HVAC system is “off”; and said pro
cessor compares at least one of the first prediction and the
second prediction to the actual inside temperature recorded
inside the structure to determine whether the actual inside
temperature is closer to the first prediction or the second
prediction.
In one embodiment, the invention comprises a thermostat
attached to an HVAC system, a local network connecting the
thermostat to a larger network Such as the Internet, one or
more additional thermostats attached to the network and to
other HVAC systems, and a server in bi-directional commu
nication with the thermostats. The server logs the ambient
temperature sensed by each thermostat vs. time and the sig
nals sent by the thermostats to the HVAC systems to which
they are attached. The server preferably also logs outside
temperature and humidity data for the geographic locations
for the buildings served by the connected HVAC systems.
Such information is widely available from various sources
that publish detailed weather information based on geo
graphic areas such as by ZIP code. The server also stores other
data affecting the load upon the system, Such as specific
model of HVAC system, occupancy, building characteristics,
etc. Some of this data may be supplied by the individual users
of the system, while other data may come from commercial
Sources such as the electric and other utilities who supply
energy to those users.

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By using these multiple data streams to compare the per
formance of one system versus another, and one system ver
sus the same system at other times, the server is able to
estimate the effective thermal mass of the structure, and
thereby predict the expected thermal performance of a given
structure in response to changes in outside temperature. Thus,
for example, if the air conditioning is shut off on a hot after
noon, given a known outside temperature, it will be possible
to predict how quickly the temperature in the house should
rise. If the actual temperature change is significantly different
from the predicted rate of change, or does not change at all, it
is possible to infer that the air conditioning has not, in fact
been shut off.
This and other advantages of the present invention are
explained in the detailed description and claims that make
reference to the accompanying diagrams and flowcharts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an example of an overall environment in
which an embodiment of the invention may be used.
FIG. 2 shows a high-level illustration of the architecture of
a network showing the relationship between the major ele
ments of one embodiment of the subject invention.
FIG. 3 shows an embodiment of the website to be used as
part of the subject invention.
FIG. 4 shows a high-level schematic of the thermostat used
as part of the Subject invention.
FIG. 5 shows one embodiment of the database structure
used as part of the Subject invention
FIGS. 6A and 6B show a graphical representation of the
manner in which the subject invention may be used to verify
that a demand reduction event has occurred.
FIG. 7 is a flow chart illustrating the steps involved in
generating a demand reduction event for a given Subscriber.
FIG. 8 is a flow chart illustrating the steps involved in
confirming that a demand reduction event has taken place.
FIG.9 is a representation of the movement of messages and
information between the components of the subject inven
tion.

DETAILED DESCRIPTION OF THE PREFERRED
EMBODIMENTS
FIG. 1 shows an example of an overall environment 100 in
which an embodiment of the invention may be used. The
environment 100 includes an interactive communication net
work 102 with computers 104 connected thereto. Also con
nected to network 102 are one or more server computers 106,
which store information and make the information available
to computers 104. The network 102 allows communication
between and among the computers 104 and 106.
Presently preferred network 102 comprises a collection of
interconnected public and/or private networks that are linked
to together by a set of standard protocols to form a distributed
network. While network 102 is intended to refer to what is
now commonly referred to as the Internet, it is also intended
to encompass variations which may be made in the future,
including changes additions to existing standard protocols.
When a user of the subject invention wishes to access
information on network 102, the buyer initiates connection
from his computer 104. For example, the user invokes a
browser, which executes on computer 104. The browser, in
turn, establishes a communication link with network 102.
Once connected to network 102, the user can direct the
browser to access information on server 106.