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Energy Conservation in a Smart Home
1Dhiren Tejani, 2Ali Mohammed A. H. Al-Kuwari, 3Vidyasagar Potdar
Digital Ecosystems and Business Intelligence Institute
Curtin University
Perth, Australia
1dhiren_tejani@hotmail.com, 2alkuwari007@msn.com, 3v.potdar@curtin.edu.au
Abstract— In recent times, developments in home automation
systems have given way to the construction of smarter
infrastructure. Such systems offer an easy way for users to
control devices in a building. Commercially, there are several
technologies that are currently being implemented for home
automation purposes namely Z-Wave [1], ZigBee [2] and X10 [3].
The proprietary Z-Wave technology has various advantages and
hence is used in this experiment. Research in this field has
extended the capabilities of the technology into areas such as
remote monitoring and control, power management, tracking &
security systems and disaster warning systems. Power
management has been of particular interest as it allows for a
greener future and is added advantage to users as a cost-cutting
measure. This paper analyses the power consumption in a
standard home taking into account commonly used appliances
and other devices and shows the management capabilities of a
home automation system as well as an estimation of the savings in
terms of power consumed and cost. The aim of the study is to
measure the energy conservation across 4 homes using a Z-Wave
home automation system. It is found that there is an 18.70%
decrease in energy consumption when the home automation
system acts to manage the power consumption of the devices in
the home.
Keywords-Power Management; Home Automation; Smart
Home; Smart Gateway
I. INTRODUCTION
Home automation systems have been steadily gaining
popularity especially in homes and office spaces. The systems
are installed with the intention of providing the user with easier
access and more control over the devices in the home. The user
will be able to monitor and control devices at home locally as
well as remotely via the internet provided the users has a
device with a compatible web browser. Generally home
automation systems can be implemented within any physical
structure provided that limitations of the technology are taken
into account before installation. A complete home automation
system consists of a Wi-Fi router or an internet connection, a
smart home gateway and multiple nodes (known as end
devices). These systems can commonly be installed in standard
homes without much hassle, making the homes smart. In this
paper, it is shown that the use of smart gateways incorporating
power management features can substantially reduce the power
consumption of a home. This in turn reflects in a reduction of
cost and carbon emissions. Commercial implications for this
technology are also tremendous with the ability for a smart
system to save up to 40% of energy that lights use in a single
building [4]. Advanced systems may also incorporate cutting
edge devices such as digital picture frames and interactive
touch surfaces [5]. The paper is structured as follows, in
section 2 we will provide a detailed tutorial on how a smart
home operates and section 3 will encompass information
regarding the type of hardware used for this experiment as well
as energy consumption measured for each of the common
devices found in a home. In section 4 we show the
experimental settings and respective measurement results
obtained and make a comparison in each section of a home.
Section 5 covers the comparison between the energy
consumption using the home automation system and when it is
disabled, followed by our comments and conclusion.
II. DEFINITION OF SMART HOME
A standard home as referred to in this paper implies a home
of four occupants having a living room, a dining room, a
kitchen, 3 bed rooms, 2 bath rooms and a garage. A smart
home is a home that has the technological capability to adapt
itself in certain situations to make areas of the home more
comfortable for its occupants while sharing a common
interface that links it to systems and services outside the home
[5] [6]. The purpose of home automation systems are to allow
ease of access to all devices within a home either locally or
remotely via the internet as depicted in Fig. 1. Appliances and
other devices around the home are networked together with the
help of a home gateway which acts as the brain of the system.
Modern home automation technologies are almost completely
unintrusive which means that there are no wires to connect the
devices to the gateway and all communication takes place
wirelessly. The numerous technologies presently available for
home automation systems offer various advantages when
compared amongst each other. These include the range of
which devices can be placed relative to the home gateway,
access delays, problems with interference and secure
communication protocols [5].
Figure 1. Layout of a home automation system.
This research has been a result of ARC Linkage Grant LP100200693 on
Intelligent real time multi-site controller for conserving energy in remote
areas and in the resource industry.
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III. HARDWARE
A. Smart Gateway
The purpose of a gateway in a home automation system is
to enable bridging between different technologies used. It also
acts as a means to connect the home system to external services
and vice versa with the help of a Wi-Fi router.
B. Sensors
A smart home is considered intelligent if it can fine tune the
configuration of the devices in real-time to improve comfort in
a particular area of or the entire living environment. Sensors
can be used to relay information on certain aspects from within
or outside the home to enable the system to adapt to the
occurring change(s). Sensors communicate directly with the
home gateway and feed the system information with regards to
light intensity inside a particular room, temperature inside and
outside the home and motion sensing to name a few.
The most commonly known cause of energy wastage is due
to human negligence. In most cases users tend to forget turning
off the appliances as they become distracted with other
activities (e. g. leaving the air-conditioning unit and television
on while going out for a drive with the kids.) A smart home
should be able to automatically turn off the air-conditioning
unit as well as the television when it detects no motion in the
room for a brief period of time.
Lighting systems integrated into a home automation system
is also an intelligent way in which to give users a simple
integrated interface that connects their entire home while
providing the added benefit of conserving energy [7]. Smart
systems that control lighting systems allow just enough light
wherever and whenever the user requires it. This is done with
the help of sensors that relay information regarding the
intensity of the light inside and/or outside the house, allowing
the system to decide if the lights should be turned on, dimmed,
or the blinds should be lifted a certain amount to allow an ideal
amount of light to flood the room/home.
C. Standard Appliance/Devices
There are many devices scattered around a home.
Depending on the size and number of occupants in a home, the
number of devices found in homes can vary. It should also be
noted that there tends to be more wastage in terms of electricity
in homes with a higher number of occupants due to human
negligence. Each household device requires different amounts
of power to run. In order to provide a valid comparison, the
power consumption of various devices commonly found in a
home was measured in real-time using an energy meter. The
power consumption is measured for each device in each home
and the average consumed by specific devices is shown in
Table 1. Some appliances could not be tested under the
circumstances including water heaters in bathrooms, water
pumps and sprinkler systems and it should also be noted that
the measurements were taken instantaneously and do not
account for the various modes that a device/machine might
have (e.g. the different cycles in a washing machine). The
power consumption of a fridge is measured and shown but the
home automation system has no impact on the system as
TABLE I. ENERGY CONSUMPTION MEASURED FOR EACH
DEVICE
Device
Power
Consumed
(kWh)
Air-conditioning unit (large)
1.7990
Air-conditioning unit (small)
0.7310
Desktop Computer
0.2174
Fan
0.0513
Fridge with built-in freezer compartment
0.1504
Garage Door
0.3417
Iron
1.5324
Laptop
0.0851
Lights (all lights in one room)
0.1374
Microwave
1.0508
Oven
2.2527
Portable heater
1.2281
Television
0.1969
Vacuum
0.8198
Washing machine
0.2564
Water kettle
2.6093
fridges are required to be on 24 hours a day and as such the
readings have no subsequent impact on the study.
IV. EVALUATION
A. Experimental Settings
We devised several scenarios which could be used to
demonstrate the energy management potential of a smart
gateway. The scenarios devised are based on a standard sized
home with four occupants and are specific to several sections
of a home.
The total hours that an appliance is turned on or off during
the period of a year takes into account the 4 seasons in a year
which are summer, autumn, winter and spring. The scenarios
that have the smart gateway disabled include random human
negligence periods in which energy wastage most commonly
occurs. As for the situations in which the smart gateway is
enabled, the amount of time that devices are switched on,
dimmed or switched off includes information relayed by
sensors connected to the network. The experiment was
conducted to measure the energy consumption of each device
within the home for when the home automation system was
turned on and for when it was turned off. We started by
measuring the power consumption of individual devices and
proceeded to measuring the total amount of energy consumed
in a day with the home automation system disabled to give an
accurate measurement for the usage of electricity in a home.
Next, we measure the total amount of energy required in a day
for a home with the smart gateway turned on. The experiment
was repeated for the other scenarios that are in different
seasons. The factors taken into account while measuring the
energy consumed included the amount and type of devices
turned on during the study as well as the duration for which it
was switched on.
B. Experimental Results
1) Living Room
In the experiment that we conducted, the living room area
had the following devices as depicted in Fig. 2. We measured
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Figure 2. Duration of devices switched on in the Living Room.
the electricity consumption based on the scenarios listed above
with respect to the four seasons following which we introduced
the multiple sensors to relay information to the system in a bid
to reduce the consumption. These were light intensity sensors,
temperature sensors, motion sensors as well as a door sensor.
The light sensors relay data to the smart gateway allowing the
system to make informed decisions in real-time with regards to
the amount of light that is present inside the living area. The
sensors also assist the temperature sensors in regulating the
temperature within the living area. The sensors placed outside
the home give a way for the system to decide if e. g. the air-
conditioner should be switched off or if the blinds should be
raised instead of turning on or dimming a light inside the living
room. Fig. 2 shows the duration of which the devices in the
living room area were switched on, with and without the
intervention of the home automation system, and the results
have been extrapolated to show the durations for a year.
As can be seen from Figure 2, the duration of the fan being
switched on is longer when the home automation system is
enabled as compared to when it is not enabled. This is because
the study done, takes into account the level of comfort that is
required by the users i.e. the level of comfort does not change
too much and is very similar regardless of the state of the smart
gateway. Although the fan is turned on for longer periods,
power saving is achieved because the air-conditioning is
switched off and replaced by using the fan to maintain the level
of comfort.
2) Dining Area
The dining area of a moderate home has two major devices
as is observed in this experiment which are lights and fan(s).
For the purposes of the energy consumption experiment, it is
assumed that the dining area only has one fan and several
lights. The same sensors as used in the living room are used in
the dining area to detect motion, temperature and light
intensity. Based on the information fed into the network by the
sensors, the gateway can then intelligently automatically
communicate with other devices to optimize comfort levels in
the dining section of the home. Fig. 3 shows the duration of
which the devices in the dining area were switched on, with
and without the intervention of the home automation system,
and the results have been extrapolated to show the durations for
a year.
Figure 3. Duration of devices switched on in the Dining Area.
Figure 4. Duration of devices switched on in the Kitchen.
3) Kitchen
Contrary to popular belief that the kitchen of a home
always consumes more energy than any other section of the
house, it has shown to be consuming less energy than several
other parts of the house in our experiment. This can be credited
to improvements over the years as there has been an ever
increasing demand for greener kitchen appliances that are more
energy efficient. Nonetheless, the home automation system still
manages to conserve some energy with regards to the lights in
the area. Modern kitchens also include exhaust fans that vent
the hot air out of the kitchen mainly to assist in keeping the
smoke out of the home which in turn also helps keep
temperature from escalating. Fig. 4 shows the duration of
which the devices in the kitchen were are switched on, with
and without the intervention of the home automation system,
and the results have been extrapolated to show the durations for
a year.
4) Master Bed Room
The most commonly found devices in the master bed room
have been taken into consideration. The experiment however
does not include mobile phone chargers but does have results
obtained from using a laptop computer. Once again, sensors
were deployed in order to relay enough information to the
gateway for it to make a calculated decision on the device
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Figure 5. Duration of devices switched on in the Master Bed Room.
Figure 6. Duration of devices switched on in the Children’s Bed Room.
on/off status. Fig. 5 shows the duration of which the devices in
the master bed room were switched on, with and without the
intervention of the home automation system, and have been
extrapolated for a year.
5) Children’s Bed Room
Nowadays, it is very common for kids and teenagers to own
at least one mobile phone and a laptop or a desktop computer.
For the purposes of this experiment however, it is assumed the
children in the home share one desktop computer and do not
own other such electronic devices and therefore has not been
taken into consideration. It is however, a very likely scenario in
which even more energy can be saved using the home gateway
system. Fig. 6 shows the duration of which the devices in the
children’s bed room were switched on, with and without the
intervention of the home automation system and its army of
sensors, and have been extrapolated for a year.
6) Guest Bed Room
Having visitors is a delight for some. Friends, family and
relatives coming over indeed brings much need fun and
laughter adding to a joyful and memorable occasion. However,
this does add to the overall energy consumption of the home
and therefore for this experiment it is assumed that there are
two guests living with the family for one week every month of
the year. Similar to the children’s bed room, although highly
Figure 7. Duration of devices switched on in the Guest Bed Room.
unlikely, it is accepted that the guests who live in the home do
not own mobile devices or laptop computers, therefore the
sensors deployed in the environment were the light intensity
sensors, temperature sensors and motion control sensors. Fig. 7
shows the duration of which the devices in the guest bed room
were switched on, with and without the intervention of the
home automation system, and have been extrapolated to show
guests living in the home for one week each month, for the full
calendar year.
7) Master Bath Room
It can be concluded that the bathrooms use the least amount
of electricity for the duration of a year and the amount use can
be insignificant relative to the rest of the house. In any case,
they have been factored into the experiment with the exception
of devices such as built-in Jacuzzis, water pumps and electric
water heaters. There can also potentially be a number of other
devices including electric shavers and hair dryers. Fig. 8 shows
the duration of which the devices in the master bath room were
switched on, with and without the intervention of the home
automation system, and have been extrapolated for a year.
8) Common Bath Room
The common bathroom is shared by the other residents of
the home as well as guests who come to visit and/or stay with
the family. Akin to the master bath room, the only devices
taken into consideration are the lights and none else, although it
is likely that there are a couple of other devices such as those
that could be in the master bath room. Fig. 9 shows the
duration of which the devices in the common bath room were
switched on, with and without the intervention of the home
automation system, and have been extrapolated for a year.
Figure 8. Duration of devices switched on in the Master Bath Room.
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Figure 9. Duration of devices switched on in the Common Bath Room.
Figure 10. Duration of other uncategorised devices switched on in the home.
9) Others
We foresee that there may be a fair number more devices in
a home than that which we have anticipated. As mentioned
previously, in a very moderate home the results shown above
and below take into account those most commonly found in a
standard home. Several other devices that do not fall into one
of the categories explained until now, are appliances and
systems that are still found in a home e. g. washing machine,
garage door, vacuum and iron. Fig. 10 shows the duration of
which other devices around the house were switched on, with
and without the intervention of the home automation system,
and have been extrapolated for a year.
V. COMPARISON
Smart devices in the home have many benefits in terms of
control. Due to a better and more controlled use of the device,
they also tend to have a longer life span and would be less
prone to damage owing to accidents when operating the
devices. We took a great deal of information in our efforts to
table the results as shown in Table 2. The table shows the
energy consumed for the period of a year in each section of
the house. The results are calculated based on previously
mentioned results and have taken into account a small number
of human negligence periods in which e. g. the user forgets to
TABLE II. ENERGY CONSUMPTION COMPARISON
Scenario
without Smart
Gateway
control (kWh)
with Smart
Gateway
control (kWh)
Difference
(kWh)
Cost
Saving
($)
Living
Room
4044.596
2780.448
1264.148
227.55
Dining
Area
183.553
123.841
59.712
10.75
Kitchen
2087.024
2061.820
25.204
4.54
Master Bed
Room
3366.062
2736.425
629.637
113.33
Children’s
Bed Room
2034.359
1404.722
629.637
113.33
Guest Bed
Room
467.336
322.776
144.560
26.02
Master
Bathroom
43.952
37.634
6.318
1.14
Common
Bathroom
46.630
39.969
6.661
1.20
Others
2516.300
2516.300
0.000
0.00
Total
14789.813
12023.935
2765.878
497.86
switch off the kitchen light or living room fan when he leaves
for work in the morning. The table shows the energy
consumed in a year for when the smart home system is
disabled and when it is actively monitoring and making
minute changes to the state(s) of the device(s) in the network
across a particular section of the house. We then calculated
the power that would be saved simply by installing the home
automation system in the home environment. As can be seen
from table 2, there can be substantial savings over the period
of a year in a standard home by implementing the home
automation system. The final row of the table shows the total
energy consumption without the smart system enabled, with
the smart home system enabled, differences between both
cases and the total cost savings over the period of a year
respectively.
VI. SATISFACTION EVALUATION
The system is evaluated by investigating the overall
satisfaction of the user(s) of the system. Overall satisfaction is
defined as the satisfaction of the user(s) of the system in terms
of the cost savings, improvements to the quality of life and
increased security. The user(s) were interviewed for their
feedback on the system to assess its efficiency and adaptability
to different homes. The user(s) were generally happy with the
integration and savings obtained by enabling the system and
provided positive experiences as well as several suggestions
on improving the system further.
VII. CONCLUSION
Smarter homes are a promising technology for the future
and are based on the principle of requiring the least human
intervention as possible while maintaining the optimum
comfort level. Extending the features of a home automation
systems make the technology even more robust in terms of
cost efficiency while reducing greenhouse gases be it in areas
of remote monitoring and control, tracking & security systems
and disaster warning systems. In this paper, we have provided
proof that there can be substantial savings in terms of energy
and cost by installing this technology in a home environment.
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REFERENCES
[1] ZWaveWorld, Inc., “Ask the Expert,”
http://www.zwaveworld.com/ask/ask8.php, February 26 2007.
[2] ZigBee Alliance, “ZigBee specification,” January 17 2008.
[3] D. Rye, “The X-10 POWERHOUSE power line interface model #PL513
and two-way power line interface model # TW523,”
ftp://ftp.x10.com/pub/manuals/technicalnote.pdf.
[4] Daintree Networks, “The value of wireless lighting control,” July 8
2010.
[5] L. Jiang, D-Y. Liu and B. Yang, “Smart home research,” IEEE
Proceedings of the Third International Conference on Machine Learning
and Cybernetics, Shanghai, 26-29 August 2004 [pp. 659 – 663].
[6] Z. Wei, S. Qin, D. Jia and Y. Yang, “Research and design of cloud
architecture for smart home ,” 2010 IEEE International Conference on
Software Engineering and Service Sciences (ICSESS), pp. 86-89, July
2010.
[7] D-M. Han and J-H Lim, “Smart home energy management system using
IEEE 802.15.4 and ZigBee,” IEEE Trans. on Consumer Electronics,
vol.56, no.33, pp.1403-1410, Aug. 2010.
[8] N. Roy, A. Roy & S. K. Das, "Context-aware resource management in
multi-inhabitant smart homes: a nash H-learning based approach," IEEE
Proceedings of the Fourth Annual IEEE International Conference on
Pervasive Computing and Communications (PERCOM'06), February
2006.
[9] S. Abras, S. Pesty, S. Ploix & M. Jacomino, "Advantages of MAS for
the resolution of a power management problem in smart homes."
[10] A. Sharif, V. M. Potdar & E. Chang, "LCARTi: Lightweight congestion
aware reliable transport protocol for WSN with sender based forward
packet drop detection," IEEE ICONIP-2010 and IEEE Sensors-2010,
January 2011.
[11] A. Sharif, V. M. Potdar & J. D. Rathnayaka, "ERCTP: End-to-end
reliable and congestion aware transport layer protocol for heterogeneous
WSN," IEEE International Conference on Advanced Information
Networking and Applications AINA 2010, Australia, April 2010 [pp.
359 - 371].
[12] V. Potdar, A. Sharif & E. Chang, "Wireless Sensor Networks: A
Survey," 2009 International Conerence on Advanced Information
Networking and Applications Workshop, 2009 [pp.636 - 641].
[13] M. Jahn, M. Jentsch, C. R. Prause, F. Pramudianto, A. Al-Akkad & R.
Reiners, "The energy aware smart home," 5th International Conference
on Future Information Technology (FutureTech), 2010.
