Small loads that add up
In our hyper-connected world, we rely on a range of devices that are always on, like internet modems and routers, and NBN boxes. But how much of a problem is that for energy usage?
Historically, one problem with ‘always on’ devices has been their ‘passive’ standby power use; for example, the power your TV uses when it’s in standby mode, waiting for you to turn it on with the remote control. However, with the introduction in 1999 (and standardisation in 2012) of minimum energy performance standards (MEPS) for many appliances in our homes, passive standby energy consumption dropped dramatically. Such standby power dropped from, in some cases, dozens of watts, to less than 1 watt for most appliances, making it much less of a problem in most homes.
But there are an increasing number of appliances making their way into our homes which we leave on, and not always in standby mode. Some of these are things we generally need to leave on because other systems rely on them—your home’s internet modem/router or a computer server in an office, for example—or because they’re part of the security system of the home—an alarm system or security cameras, for example. Others we leave on for convenience, such as a computer, so we can pick up where we left off.
Unfortunately, many of these devices don’t have a MEPS requirement or an energy star rating to help you when selecting them—and some are even chosen for you, like your internet or NBN modem.
So should you be worried about them? Let’s run through some of the common ‘always on’ appliances, their level of energy use and what you can do about it.
Unless you use mobile 3G or 4G for internet access, regardless of your internet connection type (NBN, cable or ADSL), you will need a modem/router. Modem/router power consumption ranges from under 3 watts through to 12 watts or more, dependent on features and design, equating to a yearly running cost from under $10 to over $30. It’s not a huge cost, but given that range, it’s worth considering when buying a modem. You may not have much choice as some internet service providers will only let you use the modems they supply. If they have more than one modem option, consider the one that has the lowest energy consumption rating that does what you need it to. If datasheets are not available from your provider’s website, they should be able to supply them, or check the modem manufacturer’s website.
You can reduce energy consumption to some degree by adjusting a wi-fi setting, wi-fi power output. This can be set to automatic, so that the modem only draws what it needs to in order to reliably connect with wireless devices, or you can manually set it to a power level that is less than the maximum. It may not make much difference to energy consumption, less than a watt most likely, but if it concerns you, it is worth experimenting with; just don’t mess up your other modem settings or you may lose your internet connection! Also note than many modems allow you to set a schedule for wi-fi operation, so you can set the router to turn off the wi-fi when you won’t use it, such as overnight.
Network extenders enable you to have internet access beyond the range of your wi-fi modem/router. There are two common types, wi-fi extenders and ethernet over power (EoP) boxes. Wi-fi extenders work by acting as an intermediary between your computing devices and the modem/router. Your devices talk to the wi-fi extender, which relays the data to the router, and back again.
Ethernet over power boxes work very differently. You plug in an EoP box to a power point near your modem/router and connect it to the router with an ethernet cable. You plug in the other EoP box near your computer, media player or whatever needs an internet connection, and connect it and the computer via another ethernet cable. The data travels from your computer to the EoP box, which then transmits it across the power lines in your home, using them like network cables. Any EoP box on the same electrical circuit can send and receive data to any other box.
Wi-fi extenders tend to stay active whenever they detect wi-fi signals, and so often won’t go into standby mode, if they even have this option (it’s worth checking when buying). However, EoP boxes, because they serve a single device, will put themselves into standby mode when the device they are connected to is turned off or asleep (not using its ethernet port). For example, I have a pair of ethernet-over-power boxes that allow me to play movies on my media player from my main PC. The media player EoP box goes into standby mode, drawing less than 0.3 W (compared to up to 3.7 W when operating), when the media player is turned off.
Also note that some EoP kits come with a non-wi-fi box for the router end of the network and an EoP box with wi-fi capability (as well as the ethernet connection) for the other end, for use with mobile devices. Most likely, if you have wi-fi devices running all the time, these will not go into standby mode, so it’s simpler to just turn them off at the wall at night or when not in use.
If you are on the NBN, then you most likely have a box supplied by NBN Co (in NBN terminology, this is the NBN connection point). This box provides the gateway from your modem/router to the NBN’s network. Note that not all forms of NBN connections need this box—fibre-to-the-node just needs a compatible modem called a VDSL (very high bit rate digital subscriber line) modem which simply connects to the existing phone line, like ADSL. Some ADSL modems are also VDSL compatible.
If you do have an NBN connection point device, then this will bring additional energy use, beyond the modem/router, but the amount of extra usage depends on the technology used.
For example, in fibre-to-the-curb (FTTC), one NBN distribution point unit is shared and powered by up to four homes. It requires a pretty much fixed amount of power (up to around 50 watts), regardless of how many homes are using it. So, if you are the only house using it, your NBN connection unit will power it on its own! As more homes are connected, the load is shared, reducing each home’s power draw. In this case, the only way to know how much your NBN equipment is drawing is to measure it using an energy meter, and remember that, as more of your neighbours connect, your consumption will go down.
For homes on other technologies such as fixed wireless, the energy consumption is quite stable, and generally in the order of less than 10 watts or so. For fibre-to-the-node (FTTN), the street nodes service many more homes than FTTC units, and so are powered independently using mains power. Other technologies include hybrid fibre coax (HFC) and fibre-to-the-premises (FTTP), both of which use dedicated boxes for the building connection. We couldn’t find exact numbers for energy consumption, but a commonly used FTTP box made by Lucent and used by the NBN for many installations uses up to 10 watts, so it is not insignificant. For the few people on Sky Muster satellite NBN connections, NBN Co state that power draw can be up to 70 watts maximum, easily making satellite the worst option for home energy use.
Alarms, security systems and cordless phone base stations
Other devices that are normally left on include house alarms, security camera systems and cordless phone base stations. All of these are security or safety related, so need to be left on at all times. To reduce their energy consumption, check datasheets before you buy such equipment. Power draw can vary considerably, from a watt or so to 10 watts or more per system, depending on how many sensors etc are fitted. Note that even when disarmed, an alarm system will draw a similar amount of power as when armed, as the alarm sensors, such as passive infrared sensors, are still powered up; they are simply not used to trigger an alarm. According to the document ‘Australia’s Standby Power Strategy 2002–2012 burglar alarms product profile’, the average energy consumption for domestic burglar alarms is 5.9 W continuously, or around 52 kWh a year.
Remote-control gates/roller doors
These can easily be ignored when looking for ‘always on’ loads, but the average garage door controller can use several watts on standby. We measured a unit dating from 2002 and continuous draw was 3 watts. However, modern units are generally better, and there are some sub-1 watt models such as the Merlin PowerAce. Some manufacturers don’t list standby consumption in datasheets, and we found one manufacturer who simply states ‘Low Standby Power: Yes’ which is rather unhelpful.
Another source of always-on consumption is smart devices and equipment. Smart lightbulbs, for example, generally draw less than 1 watt when ‘off’, but if you have dozens of them in your home, it starts to add up. The same goes for the smart hub (if one is needed): it’s always on and most likely using a few watts. Before filling your house with smart devices, ask yourself if you really need them. Read our analysis of smart home technology in Renew 144 for a discussion of when they can help to lower, rather than raise, energy consumption.
A good example is a smart thermostat combined with room occupancy sensors. Such a setup allows the thermostat to determine where space conditioning (heating or cooling) is required, how much is required, or even if it can be shut down, such as if everyone leaves the home but the air conditioning is left running. Such a system can reduce running costs by hundreds of dollars a year, as well as saving hundreds of kilograms of CO2 emissions a year.
Another example might be window actuators that are operated in conjunction with weather data and rain and temperature sensors. When a cool change blows through, the system can shut down air conditioning and open windows to allow in cooling breezes—something that may not happen in a manually controlled system unless the occupants go outside and realise there has been a cool change!
Before going all out, consider the embodied energy of such a system. After all, your hip pocket and the environment may be better off if you just change a few habits instead.
Appliances worth turning off
All of the devices mentioned above are quite low energy consumers in themselves. However, there are many devices that consume considerably more energy where some real gains can be made, just by turning them off or putting them into standby mode when you’re not using them.
Most computers now have a standby or hibernation mode which means you can turn them off and pick up exactly where you left off when you turn them on again. Try it, it’s life-changing! You can even have them turn off automatically after a period of time. With computers using from 5 to 200 watts (including monitor), turning them off when you’re not using them can make a big difference to your energy use and bills.
And, to reduce your bills even further, opt for the lowest powered device that meets your needs. After all, the CPUs in most computers, phones and tablets sit at around 5% utilisation (5% of their maximum capacity) most of the time for the average user. Laptops and tablets generally use a lot less power than most desktop computers, or there are low-power PCs available with excellent capabilities and high quality construction, like the Intel NUCs for example, and there are many similar machines that use as little as a few watts, take up minimal space and weigh less than 1 kilogram or so—all factors in a small environmental footprint.
As discussed in our article ‘Power without waste: building (or buying) an efficient computer’ in Renew 136, many high-performance graphics cards have very high energy use, so consider whether you need one of those—if you do, look for one with the lowest possible energy use. Check out the article for lots more tips on purchasing an efficient computer and reducing its power usage when it’s on.
You could even consider the embodied energy in the construction of your computer when buying one. There are a number of IT outlets that supply refurbished equipment that can be a suitable alternative to a new machine.
Entertainment units, printers and other IT equipment
Most other appliances should be turned off if not in use, or at least put into passive standby, so that their energy consumption is at a minimum. If they are newer devices then they should be MEPS-compliant and standby energy use will be minimal. Examples of devices that should be turned off include all entertainment devices, desktop and laptop computers, printers and other IT equipment, and any appliance that isn’t needed to be on for most of the day. Basically, if it is making heat, light or noise, it is using energy.
A big boon here is a ‘green switch’, a simple on/off switch that you can plug appliances into and then turn them all off in one go—and without having to find the power point, as it has a cord that puts the switch where you need it.
While the energy-sucking plasma TV is now pretty much a relic of the past, modern TVs can still use quite a bit of electricity. The amount varies considerably between models, generally from 20 to 700 watts, but, of course, power consumption varies with screen size, so such a range doesn’t tell you a lot unless you take screen size into account. But, given that power consumption can still be considerable, especially for the larger models, turn them off when you’re not using them. If you run an 80 watt TV for two rather than six hours a day, you’ll save 117 kWh/year, or around $32 (at $0.28 per kWh), and you will extend the lifespan of the TV by several years.
If buying new, check the energy ratings and consumption figures before you buy. A quick check of the energy ratings website shows that there are now some TVs with up to an 8-star rating. All of the most efficient TVs are LED (light emitting diode) backlit LCD (often erroneously called LED TVs, even by retailers). The more recent OLED (organic light emitting diode) TVs, while being touted by manufacturers for their very vivid colours and bright screens, don’t do any better than 5 stars. OLEDs are actually less efficient than inorganic (regular) LEDs at producing light, so even though OLED screens emit light directly to the viewer, rather than indirectly as with LED-backlit LCDs, OLEDs still need more power to produce similar levels of brightness.
However, this may change with the next generation of TVs, which are expected to be microLED displays. These involve using millions of tiny inorganic LEDs in place of OLED pixels—the higher efficiency of inorganic LEDs means much less energy used to produce the same quality of image compared to OLEDs. If you are in the market for a new TV and are considering an OLED panel, you might want to wait.
Renewable energy system losses
Solar inverters and battery systems uses some energy even when not being used. For example, grid-interactive inverters can draw a few watts continuously while the sun isn’t shining. Battery systems have losses both in their control equipment and inverters, and in the internal charging and discharging losses of the batteries themselves (no battery is 100% efficient in the charge/discharge cycle).
All of these little bits also add to energy consumed, so it pays to install the most efficient systems you can. For batteries, that usually means lithium chemistries; for inverters, that means reading datasheets and doing your homework. But don’t get too caught up in this. It makes more sense to worry about quality—after all, this equipment takes a lot of energy to produce, transport and recycle, so an inverter that lasts 10 years is going to save energy and emissions compared to one that lasts five years, even if the latter is slightly more efficient. In short, better quality is better generally, so check longevity in user reviews etc.
Some renewable energy (and related) equipment can actually be turned off when not needed. A good example is the EVSE (electric vehicle supply equipment). We checked a few datasheets, and standby power was generally in the 2 to 3 watt range. If you charge overnight and don’t use it during the day, just flip it off at the circuit breaker (if easily accessible) before you leave in the morning after the car has finished charging.
Bigger, hidden users
While all savings are good, you can get caught up in trying to save small amounts of energy here and there, while forgetting the big users. Don’t forget that the largest energy users are loads such as pool pumps, water heaters, fridges and freezers, air conditioners and heaters and even smaller loads like pond pumps that run 24/7. Some of these can be placed on timers to reduce runtime, while appliances like heating and cooling systems can be adjusted a degree or two up or down to greatly cut their energy use.
When it comes time to replace these sorts of devices, the potential energy savings by choosing the most efficient that meets your needs are considerable—potentially into the hundreds of dollars a year in extreme cases. Always check out the energy ratings website when looking for new large appliances; it is well worth the time spent.
The cost of manufacturing
One last issue to consider when buying any appliance is embodied energy. All equipment and appliances take materials, energy and resources such as water to manufacture (and eventually recycle, if that’s possible), so the longer they last, the lower their environmental footprint, all other things being equal.
Look for quality appliances with good reviews. If possible, look for ones that are supported with parts replacement if a component fails, rather than becoming waste.
Summary of actions
So, all of this sounds like a lot of work, but really it is just a matter of making a few important actions into habits.
- Turn things off or to standby when not in use. Use a ‘green switch’ to make this easier.
- When looking for new appliances and devices, check energy consumption figures through the energy ratings website or download datasheets.
- If you can’t find energy consumption data, take a plug-in energy meter to the store and ask them to let you test the device. But note: many of the cheap meters are inaccurate on small loads or loads with poor power factors, so borrow a good meter (many libraries have them) or invest in one like a PowerMate Lite which is available for purchase in Renew’s shop.
- Check reviews for early failure problems in the devices you are looking at.
- And perhaps first of all: ask yourself if you really need the appliance.
Many energy monitoring products need you to access breaker box wiring to install current clamps and the like. This is work that should be done by a qualified electrician. The Powersensor Solar Monitor, however, can be installed by the homeowner without the cost of calling in a sparkie.Read more