Watts Clever? Using a plug-in mains power meter

Published August 22, 2010 Steplight , Y Green , igreen Leave a Comment
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Watts clever plug-in power meterPlug-in power meters allow you to measure the electricity consumption of appliances around your home or workplace. A range of energy saving options can often be identified, and if nothing else, the devices will help you understand which appliances are using the most energy. The usage guide shown below is for this plug-in mains power meter available from Steplight.

Measuring Standby Loads

These are the steps to measure the standby power consumption of an appliance:

  1. Plug the appliance into the power meter.standby power foxtel box and tv remote control
  2. Turn the appliance back on to ‘stand by’ (eg, so the remote can be used on a television).
  3. Press ‘FUNC’ on the power meter twice to display the power consumption in Watts.
  4. This is how much power the appliance is using in standby mode.

So how much can be saved by turning all these appliances off at the wall?

  1. Measure the standby power (in Watts) of an individual or group of appliances.
  2. To work out the cost, find how much you pay per kWh on your electricity bill (often around $0.25/kWh), and multiply this by the hours in standby per day (an example of 20 hours per day is shown below).
  3. To calculate the approximate total savings (the power meter can do a similar calculation to this automatically if you have already entered your electricity tariff):

power meter energy standby

Measuring Appliance Electricity Consumption

There are two ways to measure appliance consumption. If you know how often an appliance is used then measure the Watts of the appliance and multiply this by the number of hours:

power meter calculationFor some appliances, power usage changes over time, so consumption cannot be calculated using the above method. This is the case for a refrigerator that turns on and off throughout the day, or a washing machine where the power used will depend on what cycle is running. You can use the power meter to work out the usage over time, and the cost, using the following steps:

  1. Plug the appliance into the power meter
  2. Set the cost of electricity on the power meter to what you pay (see manual)
  3. Leave the appliance plugged into the power meter for the desired measurement time (24 hours, one washing machine load, etc.)
  4. Come back after the specified time and press the ‘FUNC’ button until you come to ‘kWh’ for consumption or ‘Total Price’ for cost.

Download your FREE guide from Steplight

You can download an up-to-date PDF which contains the above content here: Measuring and Monitoring Energy Consumption – A Practical Guide

Understanding temperature to save energy

Published August 13, 2010 Steplight , Y Green , igreen 1 Comment
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Energy Efficiency

Temperature can be a rough indicator of appliance energy efficiency. Most electrical appliances produce ‘waste heat’ when switched on. This is because all the components inside them are not 100% efficient and the wasted energy is typically converted to heat. As such, inefficient appliances usually produce more waste heat than efficient ones (think of hot halogen down-lights, poorly insulated ovens, and so on). Do you have wasteful appliances which could be used less or replaced with energy efficient alternatives?

Building thermal imaging from closerlookpi.com

Thermal Comfort

Radiant temperature, in particular, is an important aspect of thermal comfort. You can use a non-contact thermometer to find what parts of your building are letting in too much heat in summer or sucking it all out in winter. Measure the surface temperature of a window and compare it to an internal wall. Can action be taken to better manage heat loss or heat gain through the window?

Air Conditioners

As a rule of thumb, a one degree adjustment can save around 10% off your heating and/or cooling costs. Most people find a temperature of 24-26 degrees to be pleasant in summer and 18-20 degrees suitable in winter. If you use an air conditioner or ducted heating, these are good guidelines to follow. Setting an air conditioner lower in summer typically does not make it work any faster. It will just use more electricity because the compressor will stay on for longer.

Refrigerators

Fridges and freezers often remain on their over-spec factory settings. To measure the fridge or freezer temperature, place a thermometer inside and leave it there for 30 minutes. Four degrees is recommended for your fridge and as ‘warm’ as -12 degrees is suitable for the freezer. Adjust the settings on your unit as appropriate. A freezer set at -12 will safely store foods for relatively ‘short’ periods (2-3 months). The factory settings of around -18 degrees can store food for longer periods, but this is unnecessary in most cases.

Download your FREE guide from Steplight

You can download an up-to-date PDF which contains the above content here: Measuring and Monitoring Energy Consumption – A Practical Guide

non contact digital IR thermometerSteplight’s infra-red thermometer will measure the surface temperature of an object it is pointed at. To use it, simply hold down the ‘measure’ button. For more accurate readings press the button for a longer period as it displays an average reading over this time once the button is released.

Energy Efficiency Thermometer, fridge, freezer, heating, coolingSteplight’s temperature gauge measures air temperature just like a normal thermometer, but it has a helpful guide printed down the side. It is a great tool to promote energy-efficient behaviour in your home or office.

Taking the grey out of greywater

Published August 12, 2010 Steplight Leave a Comment
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Steplight recently conducted a sustainability workshop on greywater for Liverpool City Council. Marta Lett shares some key points on the topic here…

What is greywater?

Greywater is wastewater from household areas including showers, baths, basins, sinks, washing machines and dishwashers. Reusing greywater can save up to 50,000 litres of drinking water per household per year. Reusing greywater has health implications for ourselves and the environment. Following a few simple steps will keep your families safe and your garden soils healthy.

The following do’s and don’ts of greywater reuse are adapted from NSW Health, Sydney Water and the Australian Technology Association resources.

Do’s and don’ts of greywater use

  • Wash your hands after watering with greywater
  • Use garden-friendly cleaning products that are biodegradable and low in sodium and phosphorous
  • Pipe greywater underground or under mulch to water your garden
  • Irrigate your ornamentals and orchards, making sure greywater is not in direct contact with fruit
  • Regularly check your greywater system is working properly
  • Divert greywater to the sewer during wet periods
  • Stop using greywater if someone in the household is sick
  • Don’t use greywater that has disinfectants and bleaches in it
  • Don’t store untreated greywater for more than 24 hours
  • Don’t use greywater to water vegetables and herbs that are to be eaten raw or partly cooked
  • Don’t use greywater sourced from washing nappies or soiled clothes
  • Don’t use greywater from kitchens, unless it has been treated
  • Don’t let greywater leave your property
  • Don’t use greywater that is still hot as it will kill beneficial organisms in the soil
  • Don’t spray or hose greywater.

What you put in water has an environmental effect on where the wastewater ends up (such as backyards). The chemicals in greywater can alter the condition of soils by changing their chemical composition and structure. This includes changing soil pH and the ability of plants to absorb moisture and nutrients from the soil. Soil pH testing kits and soil conditioners are available from any plant nurseries.

Laundry detergents

Choose laundry detergents that are low in sodium and phosphorous. Liquid laundry detergents tend to have lower sodium content than powdered laundry detergents. Lanfax Labs have done extensive testing of laundry detergent brands and types to determine levels of sodium and phosphorous content.

Soaps, shampoos

  • Avoid all hard soaps due to high salt content
  • Avoid products containing zinc
  • Choose products with low sodium and low phosphorous content
  • Choose body washes in preference to hard soaps, as there are no problems with soil pH being altered
  • Sodium level in most shampoos and conditioners is low
  • Hair conditioners tend to produce a low pH in soils and shampoos tend to produce a slightly higher pH in soils. As these are usually used together they are unlikely to alter soil pH.

Reusing greywater on our gardens can save as much as 50,000 litres of drinking water per household per year.

Greywater is the wastewater from household appliances including: Showers, Baths, Basins, Sinks, Washing Machines & Dishwashers – rinse cycle only.

Reusing greywater has health implications for ourselves and the environment so we need to follow a few simple steps to keep our families safe and our garden soils healthy.

Greywater is reused regularly in many households. These basic do’s and don’ts of greywater reuse gleaned from NSW Health, Sydney Water and the Australian Technology Association provide simple easy-to-follow steps.

Do’s and Don’ts of Greywater use

· Wash your hands after watering with greywater

· Use garden-friendly cleaning products that are biodegradable and low in sodium and phosphorous

· Do pipe greywater underground or under mulch to water your garden

· Irrigate your ornamentals and orchards, making sure greywater is not in direct contact with fruit

· Regularly check your greywater system is working properly

· Divert greywater to sewer during wet periods

· Stop using greywater if someone in the household is sick

· Don’t use greywater that has disinfectants and bleaches in it

· Don’t store untreated greywater for more than 24 hours

· Don’t use greywater to water vegetables and herbs that are to be eaten raw or partially cooked

· Don’t use greywater sourced from washing nappies or soiled clothes

· Don’t use greywater from kitchens, unless it has been treated

· Don’t let greywater leave your property

· Don’t use greywater that is still hot as it will kill beneficial organisms in the soil

· Don’t spray or hose greywater.

What we put in our water has an environmental effect where the wastewater ends up, including where we reuse greywater in our own backyards.

The elements or chemicals in greywater can alter the condition of soils by changing their chemical composition and structure, changing soil pH and the ability of plants to absorb moisture and nutrients from the soil. Soil pH testing kits and soil conditioners are available from any plant nurseries.

Laundry Detergents

Choose laundry detergents that are low in sodium and phosphorous. Liquid laundry detergents tend to have lower sodium content than powdered laundry detergents. Lanfax Labs have done extensive testing of laundry detergent brands and types to determine levels of sodium and phosphorous content. www.lanfaxlabs.com.au

Soaps, Shampoos

· Avoid all hard soaps due to high salt content

· Avoid products containing zinc

· Choose products with low sodium and low phosphorous content

· Choose body washes in preference to hard soaps, as there are no problems with soil pH being altered

· Sodium level in most shampoos and conditioners is low

· Hair conditioners tend to produce a low pH in soils and shampoos tend to produce a slightly higher pH in soils. As these are usually used together they are unlikely to alter soil pH.

NSW Health ‘Greywater reuse in sewered single domestic premises’, April 2000, www.waterforlife.nsw.gov.au

Sydney Water, greywater education materials, http://www.sydneywater.com.au/Education/SecondaryTeachers/Wheredoeswatergo/reusinggreywtr.cfm

The Australian Technology Association, articles published in ReNew, www.ata.org.au

Lanfax Labs www.lanfaxlabs.com.au

Reduce your energy usage and win a Home Energy Makeover

Published August 11, 2010 Steplight Leave a Comment
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Integral Energy - energy awareness campaignIf you live in the Hills Shire or Blacktown City Council Local Government Areas, you’re invited to take the Home Energy Challenge. One lucky winner in each council area will receive up to $3,000 worth of energy-saving appliances, products or services.

Register for the Energy Makeover before 16 August 2010 and you could also win an Energy Monitor to help you easily manage your energy usage.

There are 400 to be won, 200 for each local council area. You just need to register and you automatically go in the running. Energy Monitor winners will receive their Energy Monitor during September (installed by a licensed electrician).

Steplight will be coordinating the installations and follow-ups for the Energy Monitor part of this project. We also provided some advice and assistance to Integral Energy and Banjo Advertising in the set-up phase of the project. We’re excited to be a part of this program promoting practical action to reduce energy consumption in Sydney’s North West…

How accurate is the Current Cost ENVI energy monitor?

Published August 8, 2010 Steplight Leave a Comment
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The ENVI current clampsGiven the popularity of our whole-of-home energy monitor, I thought I’d do some more testing around the accuracy of the unit. In summary, I found the unit to be highly accurate for this type of device.

Firstly, you need to understand how the energy monitor works. Essentially, a current sensor clamp measures the current in your electricity supply cable. The clamp can do this without making physical contact with the cable. This data is then sent via a transmitter (in your meter box) to a display which sits inside your home.

Voltage estimation

The clamps can only measure current, so the voltage value must be estimated (because power in watts is current times voltage). The Current Cost ENVI assumes a supply voltage of 240 volts in Australia. This is quite reasonable, although future versions of the product will apparently allow users to specify the voltage. This will be useful for people with lower (or variable) mains voltage. This is often the case in rural areas because of the large distance from the power stations.

In any case, this error is usually very small and easy to rectify if you need to. For example, in my home the supply voltage is typically around 243 volts (I can measure this with our plug-in mains power meter). So, with the ENVI assuming a supply voltage of 240 volts I have an error of just over 1%. Not a big deal.

The test set-up

Moving on to the testing, I chose to test two basic scenarios. I categorised the first as ‘household consumption’ as it represents usage typical of most households. I categorised the second as ‘high consumption,’ equivalent to a small business site or very high consumption household.

The data being compared was that of:

  1. The Current Cost ENVI meter (with data being recorded every minute using the Techtoniq software).
  2. Meter readings being taken at the meter box at the beginning and end of each test period.

Given the fact I was taking visual readings of older style ‘mechanical’ electricity meters it should be noted that the error in my comparative reading itself had a potential error of around plus or minus 1%.

Scenario 1 – household consumption

  • Energy consumption varied between 126 watts and 6.5kW during the test period.
  • The test period represented an equivalent daily usage of about 16kWh/day.
  • Resulting discrepancy between the meter reading and the energy monitor was that the ENVI over-estimated usage marginally by just 1.4%.

Scenario 2 – high consumption

  • Energy consumption varied between 778 watts and 8kW during the test period.
  • The test period represented an equivalent daily usage of about 96kWh/day.
  • Resulting discrepancy between the meter reading and the energy monitor was that the ENVI under-estimated usage marginally by 5.5%.

To put those numbers in perspective, during my testing I discovered that a current clamp meter I bought from an electronics store a few years ago was itself mis-reading current by 20 to 30%. So, to measure a household’s consumption within a few percent (and with such ease) is very good news.

After all that, my results are precisely in line with the stated accuracy as advised by Current Cost. That is:

  • Readings below 1000W are typically within 1 – 3 % of actual consumption.
  • From 1kW – 10 kW the accuracy of readings can drop but will stay within about 10% of actual usage.

- Ryan McCarthy.

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