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A simple brush down and vacuum is all that you need. Similarly, remove any dust from the inlet holes or outlet grill slits. My advice is to buy a few spares – they should last for years. As this is a new product replacement filter price was not available. I estimate $30 based on other filters.

Our test was not long enough to measure its efficiency. But using another brand (OK it’s a Dyson) we have noticed a marked reduction in dust over a three-month period. As a hay-fever sufferer, I appreciate that.

The purification works in either heating or cooling mode. If you want it to operate continuously, you can set the fan to Eco or level 1.

The Coanda effect

It’s essential you understand the Coanda effect in both fan and heating mode.

First what it is NOT. You won’t get a gale force wind blowing in your face. Too many reviewers have said if they can’t feel it, then it’s not working! Sorry, this is plain wrong.

Air purifier heater and fan HFX85W20C

Because the air blows around the waist, it is more focused on a ‘precinct’. I call it a micro-climate zone. Yes, you can oscillate the fan about +/-10°, but it is not necessary. De’Longhi says the device is capable of servicing an area of 60m3. That is around 4.5 x 4.5 x 3m (ceiling).


A fan does not cool – that is a misnomer. It may induce an evaporative cooling effect if it blows on your sweaty body, but generally, it serves to move the air to provide some relief.

It has ten speeds. We tested these and associated noise levels. It ranged from 28dB (1) to 49dB (10). We found setting six the best for everyday use. The fan function uses between 5 and 35W per hour.


It has a ceramic element best known for quick heat up/down. Adjustment is from 10-28°. Noise levels range from 42-44dB.

We found it created a micro-climate zone up to 5 x 5 x 3 – slightly more with oscillation. Imagine that is a TV lounge area. Set at 22° on fan 3 (50%) it took about 20 minutes to raise the zone temperature from 18° to 22° and stayed rock solid after that.

Air purifier heater and fan HFX85W20C

ECO mode (heating only)

This is the best part of the unit. As ECO suggests, it calculates precisely the right amount of heat and fan required to economically heat a room.

We tested in a large 5 x 5m bedroom with an ambient temperature of 12°. Outside temperature was 9° going down to 4° in the wee smalls. I set the temperature to 19° which is the best temperature for sleep.

Initially, it ramps up the fan and power to bring the room to temperature. Then it very quietly keeps the room there all night. The thermostat is very accurate. It was within 2° of my Kestrel Drop Bluetooth environmental data logger.

The heater uses from 1300-2000W but is very efficient in ECO mode.

Energy use

Most Australians pay around 25-30 cents per kilowatt-hour – that is a 1000 Watts used for an hour.