The Hepa filter is used for Altitude Sleeping, Altitude Exercise, Contrast Training, IHT – Intermittent Hypoxic Training, IHHT – Intermittent Hypoxic Hyperoxic Training and EWOT – Exercise with Oxygen Therapy.
The Hepa Filter should be changed for at least 6 months or earlier if  the air in the room where the generator is installed is more saturated with particles (dust from central heating, pollen,…) or if there is an increased resistance or reduced air flow from the generator.