Airflow is required to replenish air within the canopy, maybe create a plenum or air-curtain when ports are open, etc, and to provide heating by bulk conduction (convection), i.e. circulating air across the heater element/heat exchanger/humidifier into the canopy, isn't it?
How many air-changes do you need within the incubator canopy? What airflows do you need to achieve this and maintain a steady temperature in the canopy, e.g. 10cm above the centre of the mattress, when ports are opened or closed?
Adults require about 8L/min of fresh air, when at rest, to obtain adequate O2 for respiration so 1000L/min of air is a bit excessive, for a neonate or infant, I'd have thought. At a guess 1000L is a complete air change, within a typical incubator canopy, every couple of minutes or so - CO2 from respiration a very small proportion of this.
I'd have thought that a fan might be variable speed, or at least regulated, so that a consistent airflow is maintained to ensure that fresh warm air is circulated where and when required. Perhaps when a port is opened then the airflow and heating then compensates for temperature losses.
In my experience a lot of incubator manufacturers use relatively large impellors to provide airflows driven by fairly substantial, high quality, relatively low-speed, motors. If the filter is restricting flow how about increasing its surface area?
