"Indoor air quality is of prime importance and a bad quality indoor air can aggravate existing health conditions like breathing problems and allergies. Thus, it is imperative to improve the indoor air quality in every way possible. HVAC systems have a close relation with indoor air quality and certain things need to be kept in mind in order to improve the indoor air quality in relation to the HVAC systems. Let us have a look at the factors that need to be considered to improve the indoor air quality.All HVAC systems use an air filter system which helps in attracting the pollutants and contaminants from the air and the conditioned air is sent inside. As a result, it is important that the air filter is changed or washed at regular intervals. In fact, it is recommended that at least once in a month the filter must be replaced or washed as per requirement.Similarly, in case the HVAC system is more than 10 years old, chances are high that allergens, germs, and molds develop inside the HVAC systems which in turn might affect the indoor air quality. Hence, it is recommended that systems which are more than 10 years old should be replaced with a new one.Lastly, to keep away pollutants from the indoor air, air conditioners, furnaces and ductwork should not be installed in garages or in places from where drawing in of contaminants is easier."