This energy trimmer guide is for you if you’re serious about personal sustainability at home.
And with the rising cost of energy eating into your household income, it makes good financial sense to trim your home energy use.
Step by step we’ll show you how to conduct your own free personal energy audit!
Energy Trimmer Step 1: Understanding Energy Transformation Units
Why do you need to understand energy transformation units?
Because it will help you to calculate the amount of energy the different appliances in your home actually use.
As you will see, choosing devices that save energy rather – than waste it – can make an amazing difference to your energy consumption, empowering you to make wise energy trimmer choices.
So what is energy anyway?
Energy can take many forms including movement (kinetic energy), electrical energy, heat (thermal energy), sound (sound energy), solar energy, and elevation (gravitational potential energy).
Energy also readily converts from one form to another…
So some of the heat of a boiling kettle transforms into the sound energy of its whistle; movement of two sticks rubbing together can heat grass enough to start a fire; the energy of falling water turns into the movement of a water mill; the electrical energy in a light bulb filament heats up the surrounding air…
Energy is never destroyed or created – it just transforms from one state to another.
How do we measure it?
The conventional unit for measuring energy is the joule.
One joule is enough energy to lift one kilogram about 10 cm. One kilojoule (1 kj=1000 joules) is the amount of energy it takes to raise the temperature of one litre of water about ¼ of a degree C.
Energy Trimmer Step 2: Understanding Power
Power is the rate at which energy transforms or converts from one form to another in joules per second.
1 joule/sec = 1 watt of power.
For example, a typical light bulb uses 60 W, an electric drill – 500 W, and an electric kettle – 2.4 kW (a kW is 1000 W).
When one kilowatt flows for an hour, one kilowatt-hour (kWh) of energy is transferred. The kWh is the unit by which electricity use is commonly measured and billed by power companies!
Voltage
Voltage is the rate (amount over time) at which energy is drawn from a source of electricity. The movement of energy produces a flow of electricity in a circuit.
The rate of electrical flow, or voltage, can be likened to the pressure of water in a hose – the higher the electrical pressure, the greater the voltage (measured in V for Volts).
Current
Depending on the supply voltage, and the load connected to it, a current of electricity (measured in Amps) will flow through the circuit. At a given voltage, the current of electricity will flow through the load.
The bigger the load, the lower the current – in much the same way as – at a given water pressure (voltage) – the water flow through any given part of a garden reticulation system reduces as you add more pipes to it.
Resistance
Resistance is a measure (units used are Ohms) of the load in the electrical circuit.
Materials that are good conductors of electricity offer low resistance to the electrical current flow, whereas those that are poor conductors (e.g. insulators) can retard or even block the flow of current.
So… Watt’s This Got to Do With Power????
Back to power (Watts!) again… as we need it for our energy trimmer – personal energy audit.
The power used or produced by an electrical appliance depends on both the current (flow of electrical energy) and the volts (how much pressure is being delivered to the electrical circuit).
So… Power = Current x Pressure
That is… Watts = Amps x Volts
Using this simple formula you will now will be able to work out how much power any appliance in your house uses and be well on your way as an energy trimmer!!!
Energy Trimmer Step 3: Work Out How Much Energy You Use
By law in Australia you will find a “compliance plate” on every electrical appliance sold here.
On it will be stamped either the Amps or Watts that the appliance uses to run it on our 240 V electrical grid system.
Most smaller appliances will display their Wattage. Some bigger appliances – especially those with motors in them – may just show Amps.
For example, a laser printer may be 4 Amps.
So, how much power (in Watts) does it use when it’s printing (would be a lot less when it’s on standby)?
Easy! Watts = Amps x Volts
In Australia the Watts = 4 Amps x 240 Volts i.e. 960 Watts!
A small bar fridge might be 0.8 Amps. So the Watts of power it uses when it’s running? 0.8 Amps x 240 Volts gives us 192 Watts.
OK. Now to work out how much electrical energy that is!
Simple.
Multiply the Wattage of the appliance by the number of hours you have it running and … viola! .. you get the watt-hours it uses.
Let’s say we have an electric kettle that uses 2,200 W and we use it several times a day – say it is running for 1 hour a day.
The watt-hours of power it uses up in one day is 2,200 W x 1 hr = 2,200 Wh, which is another way of saying 2.2 kWh (just divide the number of watts by 1000 to get the same figure in kilowatts).
Energy Trimmer Step 4: Conduct an Energy Use Audit
Now, run around your house and work out how much power (remember its watts times the hours it is running each day equals its power use in kWh/day) each appliance uses.
Add them up and you have your free personal energy audit!
Where We Use the Most Energy
- 31% hot water
- 26% heating & cooling
- 16% refrigeration
- 12% cooking
- 4% lighting
- 11% other
Energy Trimmer Step 5: Work Out Where You Can Reduce Your Energy Use
Reducing Hot Water Energy Use
From the graph you can see that the average household energy costs associated with different types of hot water system vary dramatically:
- LPG Storage – $700 pa
- Electric Storage – $650 pa
- Electric Instantaneous – $570pa
- Natural Gas Storage – $400pa
- Solar electric boosted – $160pa
- Solar natural gas boosted – $90pa
Obviously, it doesn’t take long for a solar hot water system to pay for itself!
So you can make real progress as an energy trimmer by changing to solar hot water heating.
If you’re stuck with an electric or gas storage system you can insulate the storage tank to make big energy savings.
To reduce hot water costs:
- Repair leaking taps
- Adjust temperature of hot water storage systems to 60°C
- Insulate hot water pipes (old polypipe works well)
- Insulate storage tanks
- Wash clothes in cold water
- Install tap-flow regulators (tap aerators and AAA showerheads)
If you live in a cold climate and use hot water to warm your home… a vital energy trimmer move is to install thermostatic radiator valves.
They are inexpensive (around $20 each) and simple for a plumber to fit. They work by sensing the air temperature around them and switch the radiator on and off accordingly.
Fitting thermostatic radiator valves throughout the home allows accurate control over the temperature in each room.
Energy savings install thermostatic radiator valves are considerable, reducing bills by preventing some rooms from overheating, rapidly recouping the installation costs.
Heating and Cooling Energy Trimmer
- Heating and cooling your home typically uses 26% of household energy.
- Each degree of extra heating or cooling costs 10% more energy!
- Close off un-used and vented areas.
- Set at air conditioning to 20 degrees C in winter, 24 in summer.
- Evaporative A/C is much more energy efficient than refrigerative.
- Ceiling fans only use what a light globe does. Use them wherever practical.
- Use a lit candle to detect sources of drafts, and seal them up!
- Paint your roof white. The new “fashionable” black roofs are just plain STUPID!!!
- Install pelmet curtains.
- Close up your house on hot days, and open it up to the breeze at night.
One top energy trimmer tip is to insulate your house.
It saves heaps of heating and cooling energy!
- Roof and ceiling insulation can save 45%
- Wall insulation can save an added 15%
“R value” is a measure of the insulative power of a material. The R value recommended for Perth, Australia is 2.5 (1-3)
Refrigeration
- Choose refrigeration devices that save energy. Check out their Wattage and energy rating.
Australian appliance energy ratings can be found here. - A box freezer is more efficient than a chest freezer as it loses less cold air when opened.
- Your refrigerator or freezer should be only as big as necessary.
- Turn off your beer or bar fridge when not in use.
- Maintain a ventilation gap at the back of the fridge.
- Keep the coils at the back clean and dust free.
- Keep the fridge in a cool place.
- Make sure the seals are in good condition.
- Let things cool before putting them in the fridge or freezer.
- Put cool things straight back in after use.
- Don’t overcrowd the fridge. Don’t understock it either.
- Jack up the front legs a bit so the door closes by itself if left open.
Cooking
- Only heat as much food or water as you intend to use!
- Use natural gas where available.
- Turn up the gas to, or use an element that fits the base of the pot.
- Allow food to thaw in the fridge before cooking.
Lighting
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Use compact fluorescent light bulbs where possible.
Each will save you about $100 over its long life – for a start they last about 8 times longer than a normal incandescent light bulb! They also use a lot less energy.
A 25 W compact puts out as much energy as a 100 W light bulb; a 15 W compact is equivalent to a 60 W bulb.
As they don’t heat up like a light bulb (which is one reason they are so much more efficient) they also don’t heat up the room or add to space cooling costs.
But they don’t suit every situation…
Where they DO suit is where lighting is habitually left on for 3 hours or more at a time, and not dimmed.
Other
Stuff left on “stand-by” accounts for about 9% of our electricity consumption!
So simply turning appliances off at the wall can slash your bills by 9% straight off.
Other tips?
- Choose energy efficient appliances.
- Turn them off when they are not being used.
- Dry your washing on the clothes line, not in the dryer!
A Case Study
The “case studies” below show how energy use habits and appliance efficiency can dramatically impact household energy use:
An Energy Guzzling Household:
An Energy Efficient Household:
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