Cost over 3 years
Most units draw 5 to 30 W on low to medium. 33.26c is Synergy's A1 rate from 1 July 2026.
What drives the cost
- Filters, by far. On our list they cost $65 to $130 a year. Over three years that can be more than the unit itself.
- Power, a little. Twelve hours a day at 20 W adds about $29 a year at Synergy's A1 rate.
- Perth conditions. Heavy smoke or dusty summers can mean replacing a filter early.
How to spend less
- Vacuum the pre-filter monthly so the main filter lasts.
- Buy filters before summer, when they can sell out.
- Choose the right size. An undersized unit runs on high all the time.