If you have asthma, then you know the signs that an attack is about to take place.  Taking in air becomes difficult, owing to the swelling of the bronchial tissue and the production of mucus, which blocks the airways.  All sorts of airborne contaminants can bring on an attack, including common things like pet dander.  In order to make sure your home is a haven from attacks, it pays to spend some time on the maintenance and upkeep of your home heating and cooling system.