Home automation

Home automation
Energy
Home automation
Home automation
In the home, appliances and equipment can be
controlled automatically and remotely. Automated
controls can turn equipment on or off, or adjust
operating settings at predetermined times; they can
be triggered on site or remotely; they can adjust
equipment operation in response to changes, such as
temperature, in the home environment. Homes using
these techniques, which may also integrate
broadband communications, are sometimes called
smart homes or smart houses.
Home automation can either be centralised and
programmable, or consist of decentralised and isolated
sensors and controls. Systems range from sophisticated
electronic programmable controls for lighting, heating,
cooling and entertainment devices using special wiring
or wireless, to just a few isolated, automated systems,
such as motion sensors to control lights.
Home automation system control board.
Home automation systems can improve the energy
efficiency of your home only if they are designed for
this purpose.
are more sophisticated switches that can activate any
electrical or electronic device. Computers or specific
controllers can automate all of these devices.
Automated systems use energy, so they produce energy
savings only if they save more energy than they use.
They are typically expensive, so take a significant time
to ‘pay back’ the savings from reduced energy costs.
Home automation energy
management strategies
Make designing an energy efficient home, and installing
high energy efficient appliances and lighting, your
first priority. Then, design home automation systems to
reduce the time that energy-using equipment operates
or the need for operating equipment (see ‘Automation
equipment, sensors and controls’ below).
Heating and cooling control
A well-designed automation system can:
▪▪ improve passive solar heating and passive cooling
through the control of blinds, awnings, windows,
vents and fans
▪▪ control heaters and air conditioners so they are used
only when and where they are needed and to achieve
a desired temperature.
Make designing an energy efficient
home, and installing high energy efficient
appliances and lighting, your first priority.
Automated systems use an electrical signal to switch
equipment — usually a light, a motor or heating/cooling
appliance — on or off. Lights can be turned on or off on
demand or based on timers or sensors. Motors can open
and shut blinds, windows and vents; they operate fans,
dampers, valves and pumps. Valves and dampers can
allow water or air to flow under the influence of the fans
and pumps. Motors and heating/cooling appliances can
be triggered by timers, sensors or thermostats. Relays
Before considering automation options, ensure that your
home is designed to make the best use of solar energy
and natural ventilation for passive heating and cooling.
(see Passive solar heating; Passive cooling)
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Energy
Home automation
Use thermostats or temperature sensors in different
rooms to control heating and cooling. Appropriately
placed, they, along with timers to control heating/
cooling appliances, can significantly reduce energy use,
even if automated systems are not used.
Well thought-out and planned temperature profiles
can minimise the energy used in heaters and air
conditioners/coolers. Consider how the temperature
of the house changes, and over what time period, before
it reaches the final temperature. Also consider just when
heating or cooling is needed.
Analyse your heating/cooling needs and how to
manage them. Ask yourself: which rooms need to be
heated/cooled, when and to what temperature? Aim
to heat/cool living areas when people are home but
heat/cool bedrooms only at night and in the early
morning when they are occupied. Bedrooms do not
need to be made as warm or as cool as living areas to be
comfortable for sleeping. Don’t heat or cool areas such
as halls and laundries, and use the appropriate heating
systems for the purposes, e.g. radiant heaters in vented
areas. (see Design for climate)
Plan your automation system. Consider how opening
and closing blinds, awnings, windows and vents can
assist passive heating, cooling and natural lighting.
Explore how switching fans and heat shifters on and off
might reduce the need for cooling or heating.
Photo: Paul Ryan
A temperature sensor is the size of a light switch.
Home automation systems can be designed to save energy.
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Energy
Home automation
Hot water control
Automate the hot water system so it can be switched
on and off as required, e.g. off when going on holidays,
on again just before your return. Solar systems can be
controlled so they do not require the use of an auxiliary
booster during summer months — and the controller
overridden during periods of poor solar gain in summer
or when demand increases, e.g. family home for
Christmas. Be aware that Legionella bacteria can grow in
water temperatures above 30°C. (see Hot water service)
Lighting control
Automate lights through motion sensors and timers,
or more elaborate centralised systems, so they operate
only when needed and switch themselves off when
rooms are vacant.
Use motion sensors to switch on external lights when
needed, or lights when entering the home, rather than
leaving lights on.
Use motion sensors to switch on external
lights rather than leaving lights on.
Photo: Paul Ryan
Motion sensors switch off lights when there is no movement
in a room.
Use motion sensors, light sensors and timing controls
to switch off room lights when they are no longer
needed, e.g. after five minutes if no motion is detected.
Give priority to rooms that often have lights left on
unnecessarily, like bathrooms, pantries and toilets.
However, take care — five minutes of inaction in front of
a TV is not unusual and you may not want all the lights
to go off then!
Photo: Paul Ryan
An external blind can help passive cooling.
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Energy
Home automation
Appliances and equipment control
Source: Switch Automation
Energy monitoring screen.
configured to measure the renewable energy generated
by a photovoltaic system or wind generator, and show
how much electricity has been exported to the grid.
Users can also view this information in real time, or view
the past week’s or month’s use. The display can also
show environmental or other measurements, such as
outside/inside temperature, and hot water temperature.
Simple energy monitoring systems are very similar to
in-home displays. (see Smart meters, in-home displays
and smart appliances)
Photo: Paul Ryan
Control screen.
Use controls to operate appliances and equipment only
when they are needed.
Remote control and timer control of appliances, from
coffee makers to home theatres to spas, can save energy
if the appliances can be switched off when not required.
But take care not to turn on appliances automatically
or at preset times — more energy may be consumed
if there is no need for the appliance to operate.
The home automation system can monitor
the total energy use of the house or even
individual circuits or appliances.
Automating equipment control to reduce operating
times is particularly useful if the appliances normally
use stand-by power when they are not operating, e.g.
stereos, TVs, DVDs and home office equipment. It is
also useful when the need for the equipment to operate
varies, such as for pool pumps, where daily operating
hours can be matched to the season.
Automation equipment, sensors
and controls
Home automation systems work by managing the electric
power of the equipment being automatically controlled.
The degree of ‘intelligence’ and how it is distributed
between the elements of the home automation system
varies with the design and manufacturer.
Stand-by power controllers (see Home entertainment
and home office equipment) are smart power boards
that automatically turn equipment off when not
being used.
Control can be implemented by isolated sensors, timers
and processors embedded in the switches and relays.
Centralised control can be obtained through networked
sensors linked to a controller or computer which then
operates the power systems of equipment throughout
the house.
Energy monitoring
The home automation system can monitor the total
energy use of the house or even individual circuits or
appliances. Current is measured by a measuring device
(which can be fairly low cost) at the meter board, and
is converted into power and energy consumption. This
information is transmitted wirelessly to an inside display
unit or directly to the automation controller. Depending
on the system installed, the user can view power,
energy, costs and estimated greenhouse gas emissions
associated with the whole house. The system can be
The operation of more sophisticated equipment such as
central heaters, air conditioners or home theatres can
also be brought under the control of the automation
system, but with more intelligent controlled devices.
Take care to ensure the controller’s instructions do not
create conflicts, e.g. heating areas that are cooled by
the air conditioner.
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Energy
Home automation
Automation systems and design
Automation equipment potentially includes any
appliance or machinery in the home whose operation
is controlled through its electricity supply, for example:
▪▪ hot water system
▪▪ appliances
▪▪ home entertainment, home office and other
electronic equipment
▪▪ lighting
▪▪ heating and cooling/air conditioning systems
▪▪ fans and air pumps/heat shifters
▪▪ powered window blinds, shutters and awnings
▪▪ powered vents and window openings
▪▪ water pumps, pool pumps and spas
▪▪ garage doors
▪▪ security systems.
A wide variety of automation systems is available and
most require a professional to design and install.
Complete packages from manufacturers offer the
hardware and software for central and remote control.
Some suppliers promote a more do-it-yourself
experience using wireless communications to connect
the controllers and sensors, but almost all systems require
a registered electrical contractor to install the equipment.
Wireless systems are more suited for installation in
existing houses, as they do not require a control wire to
be used for each switch or sensor. Some systems use
the power cabling to send the control signals.
The energy consumption of home automation systems
adds to a home’s stand-by power load. In wired systems,
the sensors, switches and measurement units are often
powered centrally. These systems have only one or
two power supplies providing power to all the units in
the system; a non-wired system has a separate power
supply for each unit. However, the power consumption
of wireless systems can also be very low, depending
on the manufacturer. Your installer or supplier should
be able to calculate overall power consumption of the
automation system, which is typically in the range of
20–100W.
Motion sensors, light sensors and temperature sensors
can be integrated into the automation system.
The home and its lighting, appliances and systems can
be controlled by:
▪▪ on-site controllers, which may be special
proprietary devices, often activated by touchscreens,
or tablets/computers
▪▪ remote controllers, allowing equipment to be
controlled outside the home or at a distance in the
home often by smart phones or tablets
▪▪ sensors that operate home equipment in response to
changes in the home environment, such as the presence
of occupants or changes in external temperature.
Check the energy consumption of home
automation systems before you buy.
Many other stand-by power loads in a home automation
system may not seem obvious, including the power
use by the audio equipment or security systems.
Examples of wired and wireless systems.
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Energy
Home automation
Their stand-by power loads can be substantial, e.g. a
multi-room audio amplifier may consume 50–100W
alone. Carefully consider the design of the system
and the components to minimise power use.
References and additional reading
Copper Development Centre. 2011. SMARTWIRED:
bringing the future home. www.smartwiredhouse.com.au
CSIRO. 2012. AusZEH (Australian zero emission house)
demonstration house. https://publications.csiro.au
Automation and electricity demand
Custom Electronic Design and Installation Association.
www.cedia.com.au
In the near future, home automation systems may be
linked to the electricity utility in a number of ways.
The utility may communicate variations in electricity
prices to a ‘smart’ electricity meter, which interfaces with
the home automation controller. (see Smart meters,
in-home displays and smart appliances)
Authors
Principal authors: Paul Ryan, Murray Pavia
Updated 2013
Householders can then program appliances to reduce
power, save energy or switch off altogether during high
price periods.
Alternatively householders could enter a supply contract
that allows the electricity supplier to send a signal to
equipment controlled by the home automation system
(such as air conditioners) to turn off certain equipment
for short periods.
The householder may choose to participate and obtain
lower electricity prices or other financial incentives as
a trade-off for allowing the electricity supplier to have
this control.
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