04.How much to buy and run?
You’ll be hard-pressed to find a ducted reverse-cycle air conditioner for less than $6000 (including installation), and the cost can easily reach twice that amount, depending on the size of your home.
The running costs mainly depend on:
- The type and size of your system
- The energy-efficiency of your system
- The time you’re operating the system for
- The construction of your home (floor plan, level of insulation, size of windows, etc.)
- The electricity tariff you’re paying
- The temperature you choose on the thermostat: each degree Celsius cooler in summer, and each degree warmer in winter will increase the running costs by 10-15%. Find the temperature you’re just comfortable with — try 25 degrees in summer, and 20 degrees in winter.
But by following some easy rules in day-to-day operation, you can further reduce running costs:
- Close all external windows and doors when your system is running.
- Shade your windows during hot summer days (to keep the heat out) and during cold nights (to keep the heat in).
- When you expect a hot day, turn on the air conditioner early, rather than wait until your home is hot. Similarly, start heating early when expecting a cold day.
Sustainability Victoria estimated the average running costs in 2002 for a 150 square metre Melbourne home at 87c per hour, assuming 15c/kWh electricity cost. Prices have of course risen since then; at 27c/kWh this would be closer to $1.57 per hour, and at 35c/kWh it would be $2.03 per hour. On the other hand, air conditioner efficiency has improved since 2002 so that would tend to reduce the cost. Nevertheless the figures show that air conditioning a whole house can be costly.
Note that the figures may be quite different in other climates, or for a different size house.