While we all want to be kept cool in summer and warm in winter, energy prices are rising every year. Whether you have or are buying an air conditioner that’s portable, a window/wall unit, a split system or a ducted system, there are some ways that you can use it more efficiently so that your bills are kept low and you’re helping the environment too.
Choosing an air conditioner
- Check how much energy it uses – Compare the cooling/heating input and output power consumption of different models, which is measured in kilowatts (kW). Also consider the size of your room, house or building and if there’s any other internal heat sources.
- Choose an inverter model with a variable-speed drive (VSD) – An inverter air conditioner (e.g. split systems) has a VSD installed on the fan motor that automatically varies the compressor’s speed. So it runs at full speed when you need to cool the place fast and it runs at a slower speed when cooling isn’t urgent.
- Pick the right size – If it’s too big for your place, it’ll have short cooling or heating cycles where it’ll switch on and off, which uses up a lot of energy. If it’s too small, it’ll have to work harder to cool down or warm up the place. Have a professional carry out full heating and cooling load calculations in your home or business to determine whether or not the air conditioner is the right size before you buy it.
- Compare energy rating labels – These labels have a star rating, from 1-6 stars, for cooling and heating efficiency. The more stars an air conditioner has, the more energy-efficient it is and the cheaper it’ll be to run too. Super-efficient air conditioners can have a rating of 7-10 stars.
Heating and cooling tips
- Close all doors and windows – This will stop non-air conditioned air, whether hot or cold, from flowing into the room, as well as stop your air conditioner from running for longer.
- Keep the area you’re cooling or heating to a minimum – You can do this by closing the doors of other rooms that don’t require cooling or heating. You can also make sure that vents and thermostats in unused areas are sectioned off.
- Check the difference between the indoor and outdoor temperatures – Whatever the temperature is outside, don’t cool down the room’s temperature to less than 8°C below it. Also, the smaller the difference between the inside and outside temperatures, the lower your cooling costs will be. Do this by setting your thermostat at a high, comfortable temperature in summer and ensuring humidity control if required.
- Adjust the temperature depending on the season – Set your thermostat between 24-26°C in summer and 18-20°C in winter. For rooms that are used infrequently (e.g. toilets and storerooms), the temperature should be 16°C in winter.
- Don’t set your thermostat at a colder temperature than normal – Your home will not cool down any faster and can result in overcooling.
- Use the economy mode – This will reduce energy usage by maintaining moderate temperatures in the right conditions.
- If you have a central cooling system, use the zoning options – This will allow air to flow to only certain areas of the house.
- If you have a central air system, have the fan shut off together with the compressor – Set the ‘auto’ mode on the fan setting to do this and use fans in individual rooms instead.
- Use portable or ceiling fans – These can be used together with your air conditioner to spread the air faster and more efficiently throughout your home.
- Ventilate at night or early in the morning – Close the windows during the day and open them at night or in the early morning to let in some fresh air.
- Turn it off when the temperature outside drops – You can then let the cool air inside by opening the doors and windows.
- Turn off other internal heat sources – These include lights, computers, printers and ovens. They can add to the heating load, so turn them off when not in use.
- Use energy-efficient lighting and office equipment – They will not emit as much heat as less-efficient products. For lighting, use compact fluorescent light bulbs.
- Only use it when needed – Your air conditioner should only run when you’re using the room. For commercial buildings, it should be turned off at the end of the business day and on the weekends.
- Use timers – You can reduce the number of hours the air conditioning system runs for by using timers. The system will switch on when someone enters the room and switch off when they leave the room.
- Use a programmable thermostat – This is great for commercial buildings, as it’ll turn on the air conditioning system 30 minutes before people arrive and turn it off 30 minutes before they leave at the end of the day.
- Ensure good air circulation around the inside and outside units – Remove curtains, furniture or plants that may be blocking the inside unit, and also clean the filter. For the outside unit, remove dust that may be blocking the heat exchanger, as well as plants that are obstructing the airflow.
- Cover the outside unit from the sun – Use an awning or a shade mesh to ensure that the unit doesn’t overheat.
- Don’t confuse the temperature sensors and thermostat – If there are other heat sources near the air conditioner, such as a lamp or TV, place them somewhere else so as not to influence the sensors on the wall or unit, as well as the thermostat.
- Don’t do things that will increase the room’s humidity – Don’t have a long hot shower, mop the floor or dry the clothes. Only do these things in the evening when it’s cooler.
- Make sure ducting is free of air leaks – Cool air that escapes will cool the inside of your roof rather than the inside of your home.
Long-term energy-saving tips
- Replace your old air conditioner with an energy-efficient one – Look for the ENERGYSTAR label and compare EnergyGuide labels. When compared to standard models, a room air conditioner with these labels is 10% more efficient and a central unit is 15% more efficient. Overall, energy-efficient air conditioning systems use up to 40% less energy than older models..
- Use a heat recovery ventilation system – This will use waste energy from exhaust air to condition incoming fresh air.
- Make use of waste heat – If your business utilises heat-generating processes like cooking or distributed generation, use heat recovery to capture free waste heat.
- Insulate the home or building – Insulate roof spaces, ceilings, walls and pipes to reduce heat loss in winter and heat gain in summer. Hot and cold air ducts should also be insulated.
- Install double-glazing windows – They can also significantly reduce the amount of heat lost during winter and the amount of heat that enters during summer.
- Shade the window from outside – Use an awning, shutters, blinds, drapes or tinting to reduce the amount of sunlight entering the room in summer, which can decrease the room’s temperature by a few degrees. In winter, keep them open during the day and closed at night.
- Use skylights – They allow natural light to enter inside, which is great during winter. In summer, however, consider covering them up.
- Use a dehumidification system – If you live in a humid climate, this can increase your comfort when it’s very hot, which means you can just use a small air conditioning system.
- Consider installing economisers – They’re great for when the temperature outside is lower than the temperature inside. They’ll take fresh outdoor air to cool the inside, so you won’t have to use the indoor air conditioner to cool the inside with recirculated air.
- Utilise an energy management system – It’s best to use this if your air conditioning system can’t be controlled with timers or thermostats. You can use different cooling and heating temperatures for various zones, stop times, optimum equipment start, and more.Maintain it regularly – Follow the manufacturer’s maintenance instructions to ensure that your air conditioner is operating as it should be. This includes maintaining the system, as well as cleaning and replacing the filters on a regular basis.
- Get it checked by a specialist at least once a year – A specialist can confirm if the air conditioner is in tip-top condition by checking that all the functions are working properly.
When used correctly, air conditioners can make any environment feel pleasant and comfortable. And with these energy-saving tips, you can reduce your energy bills and be more eco-friendly at the same time.