Carbon Monoxide Detector

• Carbon monoxide is emitted as a result of the incomplete burning of carbon fuels. In most cases of indoor carbon monoxide poisoning, gas appliances are the culprit. Because carbon monoxide is odorless, you may not know of a leak until it is too late if no carbon monoxide detector has been installed. A responsible homeowner or building supervisor will make sure to install carbon monoxide detectors, sold where you find smoke detectors, often bundled as a two-in-one product.
  
  

Hydrometer

• Most hardware and specialty stores carry a device called a hydrometer, which measures moisture. A digital hydrometer can be wall-mounted like a thermostat. Irritants and bacteria thrive in air that is too moist, and dry air can cause shallow breathing, wheezing and coughs. With a hydrometer you'll know where you stand before deciding to purchase a humidifier or dehumidifier.
  
  

Air Purifiers

• Air purifiers lower the amount of dander, pollen, smoke particles and other pollutants from the air you breath. They are especially recommended for allergy sufferers who are more sensitive to airborne particles. The U.S. Department of Energy has set a standard known as HEPA for air purifiers. Air purifiers with HEPA certification remove 99.97% of 0.3-micrometer particles.
  
  

Tools for Moisture Control

• Exhaust fans are essential in kitchens and washrooms to move excess moisture out of your house. Carpets should be vacuumed often to keep them dry. When they are moist they become hosts to harmful irritants. To test an old carpet for moisture problems, cut a small piece and place it into a sealed jar. Put the jar on a sunny window sill for one day. If there is a foul odor, it is best to discard the carpet or take it to a specialty cleaner.