A customer was wondering if they had to replace their entire evaporative airconditioner due to the unit not effectively cooling their home anymore.

We go through a series of questions to target the problem, are all the filter pads getting evenly saturated, How is the water level and condition of water, is the pump and fan running OK also if the bleed-off tube isn’t running while the pump is on, it will cause calcium build up on the pads etc and cause erosion, inefficient cooling and having to replace your pads more frequently and finally how old is your filter pads?

Aspen Fibre Filter Pads V’s CELdek Filter Pads

There is two types of filter material for evaporative airconditioners, Aspen Fibre (which most people describe it like a straw or wooden shavings) the other is CELdek (most people say it looks like honeycomb or cardboard). The two filters have different features and benefits.


Aspen Fibre– Mainly used in old evaporative airconditioners. The pads are inexpensive, ie. Average unit costs approximately $30 per filter to replace.

The filter should be changed every 2 years, if not, the filter ends up sagging and can cause the water to be drawn into the unit which causes numerous problems (water damage motor, pump etc and even house flooding).


CELdek- CELdek is a very efficient fibre, CELdek lasts up to approximately 15 years (depending on water conditions) or longer if rainwater is used. It is more expensive than the Aspen (approx 3 times) however it has a longer life span, more efficient and stronger. It is thick and absorbs a lot more water than the Aspen, therefore the air becomes colder. The time to change this style of filter is when you take the pad out and if it is heavy and no light appears through the pad.


Your choice- People choose one type of filter over the other for various reasons, this is the fact to go by and we let the customer make that choice, having said that, our units for the past 20 years have been manufactured with the CELdek and are not compatible with the old Aspen style