The Aprilaire 700 Automatic is an evaporative humidifier, which simply means that it evaporates water to increase the amount of water vapor in your air. But be warned that you'll probably need an expert to install it, because it isn't a standalone unit. It works directly with your existing HVAC system. It can humidify as much of 4,200 square feet of air, assuming that you have a well-insulated ventilation system.
Unlike clouds and fog, water vapor is an actual gas, as transparent and odorless as the oxygen and the nitrogen that also make up our atmosphere. Although not all air contains water vapor, a certain amount is desirable because it keeps our skin from drying out and helps suppress allergens that would otherwise find their way into our respiratory systems. Humidity is the amount of water vapor in the air. That's why we use humidifiers when the air gets dry.
Humidifiers like the Aprilaire 700 Automatic put water vapor into the air by using a fan to drive dry air through a water panel that's kept continually damp. As the water evaporates -- literally, turns into a gas -- it becomes a part of the air and circulates into the HVAC system that the humidifier is attached to, spreading the newly humidified mixture of gases throughout the surrounding house or building. That's why the Aprilaire is referred to as an evaporative humidifier.
If you'd prefer a standalone unit that simply humidifies a room rather than a whole house, consider the Dyson AM10. And if you'd prefer a steam humidifier rather than an evaporative one, try the Aprilaire Steam 800.
One feature that I really liked was that because it has its own fan, the warm air from your furnace is simply circulated through the unit and back into the duct.
Keeps the humidity at a steady level so we don't have to run down the basement with out door temp changes. I would recommend this unit.
I am totally satisfied with this product. Works better than other brands it replaced. Get the digital system. Highly recommend it.
We had to play with the settings to get just the right level but we have been very happy with this unit and highly recommend it to everyone!