Return vent filters are needed if there is no air filter in the HVAC unit. If there is an air filter in the HVAC unit, then return vent filters should not be used.
Filter cleaning is a task that is commonly regarded as unnecessary or of low priority. In fact, it is one of the key steps to keeping an efficient system and a healthy environment. Ducted air conditioning circulates through the whole house starting in the indoor unit, blowing out through the vents, feeding through the return air grille before returning to the indoor unit where the cycle starts again. That’s why it is vital to keep a clean filter because the air feeds through here and recycles through your home.
If you don’t clean your filter, the dust and lint will build up and consequently restrict the air flow back to the fan coil (indoor unit). If the air flow is restricted, the system has to work harder by using more power to try and suck the air through. This will inadvertently increase your power bill. If the dust and lint is blown past the filter it can potentially damage the fan coil. The dust and lint may pass through the fan coil and circulate through your home creating polluted air which could create health issues.
