By Julie Curnow

How To Keep Your Ducted Reverse Cycle Air Conditioning Running Costs Down

Most of the battle in minimsing ducted reverse cycle air conditioning running costs is choosing the right system in the first place. There are a couple of things you can do with your existing system – check out steps 3 and 4.

1. Check Out The Efficiency

  • Energy Efficiency Rating (EER) and Coefficient of Performance (COP) are measures of how efficient an air conditioner is on cooling and heating mode respectively.
  • The higher the EER and COP the more efficient the unit is and the lower it will cost to run than an equivalent model with a lower EER and COP.
  • EER and COP are required to be stated on all air conditioning manufacturers’ brochures.
  • The EER and COP are under standard test conditions and so doesn’t measure the benefits of reduced running costs when the fan speed and thus air flow are lower. In Australia, the Actron ESP range of air conditioners are the only models which allow the compressor to slow down to 10% of capacity. The Actron ESP fan speed can reduce to 20% of maximum capacity. Most inverter air conditioners can only reduce fan speed by 50% or less.

2. Get A Properly Designed System

Design of ducted reverse cycle air conditioning

  • Get the correct sized air conditioner – Under sized and your unit will be working too hard. Over sized and you are treating air you don’t need. The best way to get the correct sized air conditioner, is to buy from a specialist air conditioning dealer you trust. Ask for a heat load with your quote showing the maximum load on the air conditioner (so you know it is sized correctly) and which zones are designed to be turned on simultaneously (so your system is designed for how you want to use it) .
  • Use zoning – Zoning entails splitting the home into areas (zones) which can be turned on or off. This reduces running costs as you are not air conditioning the whole house all the time. For example the family room in the above plan (shown in green) is one zone and 2 bedrooms are another zone (yellow). It is vital that the person who designs the air conditioning system knows what they are doing or you will get an inefficient system that doesn’t save you any money.
  • Ensure the ducting has a high thermal insulation, “R”, rating. Air and Water Residential is one of the few air conditioning companies to use R1.5 ducting, BCA Minimum Duct Requirements for Western Australia.
  • Use components that don’t leak. Air and Water Residential use Airstream components which are guaranteed not to leak air and is the only R1 rated air distribution system on the Perth market.
  • Outdoor unit location. The outdoor unit works up to 10% more efficiently in a shaded location rather than in full sun.

3. Turn The Dial

AirStream iZone controller

  • Set a sensible temperature. Thermostats should be set between 24-27°C during summer. Every 1°C lower can increase running costs by up to 15% or cost you for repairs because they do like a break every so often. Also air conditioners work less efficiently at maximum capacity so using the highest fan speed setting all the time will cost you more.
  • Use pre-cooling. If there is a few hot days forecast, then pre-cool your house the night before. This is especially effective if your house has a high thermal mass such as solid brick. This will allow your air conditioner to work at its optimum during the cool evening, saving power and wear and tear on the unit. It also allows the unit to keep on top of the heat load as it begins to warm up during the heat of the day.

4. Keep It Clean

The most important thing with reverse cycle air conditioning is to clean the filter at least every two months. If the filter gets clogged up with dirt and dust it will cut efficiency up to 50%, increase noise and increase operating costs as the air conditioner has to work harder to achieve the air flow. Cleaning the filter is simple:

  • Ducted system – turn the unit off, flip the return air grille down, remove the filter and give it a vacuum.
  • Split system – turn the unit off, flip the fascia down, remove the filter and give it a vacuum.

Always read the manufacturer’s instructions. Some systems eg Daikin and brands with the iZone controller have reminders when the filter is dirty and requires cleaning. Call the specialists at Air and Water Residential on 08 6363 5343 if you want help with choosing your new ducted reverse cycle air conditioning.

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