Asthma - Studies have shown that high humidity levels result in dramatically higher numbers of house dust mites. Dust mites are one of a number of asthma triggers.

Allergies - Spores from moulds and metabolites found out high humidity's can initiate allergies in susceptible people.

Stress - At higher humidity's the human cooling systems based on respiration do not work as well. This can contribute to short and long term stress levels.

Comfort - Eyes, noses, throats and skin are all adversely affected by low levels of humidity.

Electric shocks! - At low humidity's static electric shocks become more powerful. Thankfully these are not life threatening!