Mold is number one health problem with one in every three persons affected by mold and one in ten with a severe problem related to mold. These can range from common cold, tonsillitis, otitis, sinusitis, bronchitis, asthma, and pneumonia, to cancer. Check your home's humidity levels; buy or borrow a hygrometer and watch changes in R.H. that occur throughout a typical day in different rooms of house and over heating season. To inspect your home for mold growth, winter is best time except for basements which should also be inspected in summer. With a flashlight and some simple tools, go through entire house, both inside and outside, searching for moisture damage and mold growth and their potential causes.

The Stachybotrus species of mold is dangerous; it will start growing in 80 percent humidity but, once established, can grow at 55 percent humidity. This mold can develop from decay of building materials and is much harder to control. If more than ten square feet develop, it is advised that a professional clean it up. When you see a small speck of mold, that's only part of problem - remainder being inside walls.

'Frog Page' is a manual of health of environment and states that frogs are declining because of mold.

Some of causes of mold are brush and trees within 30 feet of building; venting clothes drier inside home; furniture against outside walls; old fill, causing building movement leading to cracks causing water ingress; concrete will wick up water even to several feet above ground; ventilation not directed outside, such as kitchen range hood, which should be vented outside; plants and aquariums; drying clothing indoors; standing water, such as keeping cold water in kitchen sink; hot tubs; using several gallons of water to wash floors.

'Sick Building Syndrome' is caused by moisture and mold growth. It migrates through foundations up from soil. A dehumidifier is not final answer as it only does air and not walls. What is required is a combination of ventilation, circulation, and heat. Carpenter ants and termites will smell moisture from miles away and they only attack damaged wood.

Ventilation alone won't help a crawl space. In summer vents bring in warm, moist air.

Mold forms on coldest space. The only way to deal with it is with heat. Wall heaters with fans are more efficient than baseboard heaters.

Pull furniture and store material away from exterior walls and off basement floors; leave closet doors ajar; leave bedroom doors open as much as possible; undercut doors; don't block or deflect warm air registers; open drapes, blinds, and curtains; set furnace fan to run continuously. This will use more electricity but can be offset by installing a two-speed energy-efficient motor; don't cut off heating supply or close off unused rooms.

Uninsulated or poorly insulated areas such as exterior corners or foundation walls, should be improved with additional insulation. Be sure to install an air-vapor barrier, usually polyethylene, on room side of insulation to prevent hidden condensation behind insulation. Seal hidden opening into attic, tighten attic hatch, weatherstrip and caulk around windows and doors, gasket electrical outlets, caulk baseboards and seal top of foundations. Using an air conditioner on muggy summer days also helps take out moisture.

Humidifiers, dehumidifiers, air-conditioning units and filtration systems can be a source of mold growth if they are not regularly cleaned.