Watch Your Water
Discussion of the design of your home’s HVAC system should include controlling the moisture levels appropriate to the climate in which you live. The addition of moisture (humidification) may be required in colder climates during the winter season and removed (dehumidification) during the summer months. Extreme moist warm climates may require additional dehumidification beyond what your air conditioner can provide.
Your ACCA contractor of choice is the professional who understands the building science of your home and applies the design principles contained in the ACCA design manuals and practices.
Winter Humidification
Relative humidity (RH) is the percent of moisture in the air compared to the maximum amount of moisture this air can hold at the same condition. Warm air will hold more moisture than cold air, and as cold ventilation air mechanically or naturally (by infiltration) enters your home, it can be drier than the driest desert and seriously lower the humidity levels in your home. The psychrometrics of air show us that at 70 degrees F air can hold about 12 times as much moisture as 10 degrees F air, and when 10 degrees F outside air is heated to 70 degrees F the humidity level goes from 70 percent to 7 percent. Normal household functions (such as cooking, showering and laundry) also have an impact on the relative humidity within your home and hence on your comfort.
The effects of bacteria, viruses, fungi, respiratory infections, allergic rhinitis and asthma, and ozone production can be minimized by higher humidity levels. Studies have shown that wintertime operation at 68 degrees F / 60 percent RH provides the same level of occupant comfort as does 72 degrees F / 30 percent RH; so lower utility bills also results with the addition of moisture to your home.
Automatic, computer-controlled humidifiers can control the right humidity levels in your home, providing enough moisture for a healthy comfortable home within the limits to prevent window and cold surface condensation.