PROS AND CONS

BYPASS FLOW-THROUGH - Pros: Bypass flow-through humidifiers are low-cost and low maintenance. Depending on the hardness of the water supply, the only necessary maintenance is to replace the humidifier pad once a year. The drain tube should also be checked yearly and cleaned if there is mineral build-up inside.

Bypass flow-through models cost less than other models - and are easier for contractors to install because there is no heating element and no fan or drum motor.

Cons: First, because there is no separate fan or motor, bypass flow-through models deliver rated humidification only when the furnace is operating. In some applications, there may not be enough furnace run-time to deliver the needed humidification. Also, there is a higher rate of water use. Relatively little of the water used in a bypass flow-through humidifier is actually converted to humidity. Most of the water is used to flush the humidifier pad to minimize the clogging effect of mineral build-up.

DRUM -  Pros: Drum bypass humidifiers can be installed with or without a flushing timer. A non-flushing model is ideal for use in applications where there is no drain location, e.g., in homes without central air.

A non-flushing drum humidifier is a good choice for areas with high water/sewer bills. It converts all the water it uses into humidity, so it can condition a large space yet use five gallons or less of water per day.

Cons: A drum model without a flushing system is high-maintenance. Without flushing to clean it deposits from the evaporated water build up in the reservoir. A drum humidifier typically needs cleaning every one to two months.

In applications where a drain is available, a flushing timer can be added to a drum unit to make it about as maintenance-free as a flow-through humidifier. Honeywell offers an optional automatic flushing timer for its bypass drum humidifier.

POWERED FLOW-THROUGH -Pros: Like bypass flow-through, powered flow-through are hard-water tolerant and minimal maintenance - just change the pad.

The fan inside a powered unit blows heated supply-side air across the humidifier pad so its water efficiency is higher. Powered models can typically produce about one gallon more humidity per day using the same size humidifier pad as a bypass model.

The additional electricity needed to run the fan is minimal - about equal to a 25 watt light bulb - and could be more than offset by the energy-savings possible with lower thermostat setting when the air is kept at an optimal humidity level.
In addition, powered flow-through humidifiers do not require a bypass duct, so they can be installed in tighter spaces. In fact, there is a specific market niche for powered models - geographic areas like the Southeast and Southwest where homes are built on slabs and where HVAC systems are installed in closets, with minimal room for the mechanicals.

Cons: Because it includes a separate fan, a powered flow-through humidifier costs more to purchase and operate than an unpowered model.
 

BYPASS FLOW-THROUGH HUMIDIFIER

DRUM HUMIDIFIER

POWERED FLOW-THROUGH HUMIDIFIER

Bypass Flow-Through Humidifier-The most popular type

ENHANCE YOUR COMFORT AND PROTECT YOUR HOME   Maintain your home’s most comfortable humidity level automatically with a Honeywell Bypass Flow-Through Humidifier. Proper humidity provides a more comfortable living environment at a lower temperature, so you can turn down your thermostat for energy savings.

Controlling humidity also means moisturizing dry air to prevent damage to hardwood floors and woodwork.

A bypass flow-through humidifier uses a bypass off the supply or return airflow to create pressure that draws the airflow into the humidifier and through the moisturized pad. The result is an even distribution of humidity in the air throughout your home.

Features:

Drum Humidifier-For homes in areas where water costs are relatively high

ENHANCE YOUR COMFORT AND PROTECT YOUR HOME   Maintain your home’s most comfortable humidity level automatically with a Honeywell Whole-House Humidifier. Proper humidity provides a more comfortable living environment at a lower temperature, so you can turn down your thermostat for energy savings.

Controlling humidity also means moisturizing dry air to prevent damage to hardwood floors and woodwork.

The humidifier pad in a drum unit is mounted to a motorized cylindrical drum. The motor rotates the pad through a reservoir of water, picking up moisture. Air is bypassed from the supply side, passed through the wetted pad to become humidified, and mixed with the return air.
 

Features:

Powered Flow-Through Humidifier-More easily installed in tight spaces

ENHANCE YOUR COMFORT AND PROTECT YOUR HOME   Maintain your home’s most comfortable humidity level automatically with a Honeywell Whole-House Humidifier. Proper humidity provides a more comfortable living environment at a lower temperature, so you can turn down your thermostat for energy savings.

Controlling humidity also means moisturizing dry air to prevent damage to hardwood floors and woodwork.

A powered flow-through humidifier has a built-in fan to draw airflow into the humidifier and across the pad. The humidifier mounts right to your furnace and no bypass ductwork is required, making installation easier.

Features: