In today's eco-conseious world the washable air filter is seeing a revival, and with new technology there is good reason to consider washable air filters for some applications. While the metal air filter remains the most commonly thought of washable air filter, there are other better options now avaiable. Metal air filters stop so little particulate their use is limited and advances in filter technology give us better cleanable and reusable options to the metal air filter.
Still used by many OEMs, the metal air filter is still put in many Make-Up Air units at the factory. This is done purely out of habit, and the fact that the filter makers have been able to cheapen up this product to still make it "economical" for the OEMs. However, with a growing focus on air quality the low particle removal rate of these filters (only about 20% Arrestance) makes them of no value to most building owners/occupants. Another issue of growing concern is that even though they don't catch much metal air filters still restrict airflow (a.k.a. use more energy) at a high rate compared to other reusable air filter options.
Washable air filters are best used in the following applications:
- Make-Up-Air Units where filter bank is exposed to the outside
- UnitVent and Entryway units
- Household/Residential Systems
- Exhaust or Return Air for Swimming Pools
- Over Coils for Ice Machines/Refridgerators/Coolers
- Electrical Cabinets
A quality washable filter should last between 3-10 years depending on how "tough" the environment is on the filter. A Make Up Air unit where the filter sits outside is going to be more harsh on the filter than a unitvent or residential system and that will impact filter life. With Electrostatic air filter media making advances in recent years it has made the washable filter now a good and viable options in "medium" efficiency applications. Where High-Purity is required a fine-fiber filter is still best, but over half of the air filter market in the United States is the "medium" efficinecy catagory.
For a sustainable solution that gives great energy performance, offers medium efficiency, and won't fill up landfills electrostatic washable filters are a great option. It is important to distinguish a difference between these electrostatic washable air filters and electrostatic precipitators or PECO type devices - both of those require electrocoty to boost the electircal field of the filter where the electrostatic cleanable filters do not require extra electricity to function properly.