Pros And Cons Of Whole House Humidifiers: Bypass Versus Drum

19 October 2015
 Categories: , Blog


Running your furnace often during the winter can strip most of the moisture from the air and leave your skin feeling dry and chafed. A whole-house humidifier can hook up to your furnace and add moisture back to the air so you can stay warm and chafe-free throughout the season.

There are different types of whole-house humidifiers available that hook to furnaces but a bypass humidifier is one of the more common units. What are the pros and cons of a bypass humidifier – and how does the unit stack up to the drum style, which is another popular type of whole-house unit?

Pro: Lower Maintenance than Drum

A bypass humidifier involves less maintenance than a drum unit, and that's because of how the water is collected for the moisture. Both types of unit involve a moistened pad that adds condensation to air passing through towards your ducts. But the bypass pad is moistened directly by a water inlet from the main water supply while a drum unit has a standing pool of water that a rotating pad dips into for the moisture.

The standing pool of water in the drum unit stays there until the pad has used up enough water to trigger the water inlet to refill the pool. But all of the water isn't gone when the refilling happens so some stagnant water starts to get recycled by the system. Stagnant water can lead to bacteria buildup and potential health problems for you and your family.

To combat the possible stagnant water, you would need to frequently check and clean both the pool and the pad to remove any growing bacteria and mineralization from the water.  

Tie: Only Runs When the Heater Does

The bypass humidifier and the drum humidifier both only run when the furnace is running as the furnace's blower supplies the hot air the humidifier moistens. Steam humidifiers can run whenever the humidity levels drop low regardless of the furnace operation,  but a malfunctioning humidity gauge can force the air to become far too moist or far too dry.

Running only with the furnace also keeps your utility bills lower. The water on a bypass humidifier will run less often to moisten the pad and the electricity controlling the unit won't be in as much use while the furnace isn't running.

Con: Less Water Efficient than Drum

While a bypass unit can help save on power bills when it is off, a bypass unit will add more to your water bill than a drum-style unit. The reason is explained in the maintenance section: constantly refreshing water is less water efficient though cleaner than the pool-style setup.  

For professional HVAC services, contact a company such as Absolute Air.


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