A high-efficiency whole-house large bypass evaporative humidifier engineered with water recirculation technology to reduce wastewater discharge. The AprilAire 620A delivers up to 18 gallons per day (GPD) of moisture distribution for homes up to 5,300 sq. ft. Built with an internal recirculation valve that continuously recycles water over the HydroCore™ evaporative cartridge, the 620A achieves up to 55% less wastewater compared to conventional bypass humidifiers. Equipped with the Model 62 Automatic Digital Humidifier Control and outdoor temperature sensor, the system dynamically modulates indoor relative humidity based on outdoor ambient winter conditions to protect architectural millwork and maintain comfort across Canadian heating seasons.
Technical specifications
| Warranty | Your AprilAire® Humidifier is expressly warranted to be free from defects in materials or workmanship for five (5) years from date of purchase. Source: AprilAire warrantyWarranty is provided by the manufacturer under its own terms. See the source link for full details. |
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Key features
- HydroCore™ water recirculation — internal valve recycles water over the evaporative cartridge, reducing wastewater by up to 55% while maintaining continuous panel saturation.
- Automatic digital humidity control — includes Model 62 digital controller and outdoor temperature sensor to dynamically modulate indoor humidity and prevent window condensation.
- High evaporative capacity — delivers up to 18 gallons per day, providing comprehensive humidity coverage for residential layouts up to 5,300 sq. ft.
- Modular cartridge replacement — self-contained HydroCore™ cartridge simplifies annual maintenance and prevents mineral scale accumulation within the chassis.
- Reversible bypass duct collar — 6-inch round bypass duct collar mounts on either the left or right side of the unit for versatile mechanical room installation.
Sizing guide
| Tight construction (modern building code, 0.5 ACH) | Up to 5,300 sq. ft. (492 m²) |
|---|---|
| Average construction (typical residential, 1.0 ACH) | Up to 2,600 sq. ft. (242 m²) |
| Loose construction (older heritage structure, 1.5 ACH) | Up to 1,800 sq. ft. (167 m²) |
Specifications
| Manufacturer | AprilAire |
|---|---|
| Series | 620 Series Evaporative Bypass |
| Model / SKU | 620A |
| Equipment type | Whole-house bypass evaporative humidifier |
| Evaporative capacity | 18 Gallons Per Day (GPD) @ 120°F plenum temperature |
| Coverage (tight construction) | Up to 5,300 sq. ft. (492 m²) |
| Coverage (average construction) | Up to 2,600 sq. ft. (242 m²) |
| Coverage (loose construction) | Up to 1,800 sq. ft. (167 m²) |
| Wastewater reduction | Up to 55% less water discharge vs standard bypass |
| Control included | Model 62 Automatic Digital Humidifier Control |
| Outdoor temperature sensor | Included (digital proportional reset) |
| Replacement water panel | HydroCore™ Cartridge (Model HYDRLH / HYDROL) |
| Bypass duct connection | 6 in. round duct collar (reversible left or right) |
| Plenum opening dimensions | 14-3/4 in. W × 14-5/16 in. H (375 × 364 mm) |
| Unit dimensions | 15-5/8 in. W × 15-7/8 in. H × 10-1/4 in. D |
| Electrical rating | 24 VAC, 60 Hz, 0.5 A |
| Transformer included | 120 VAC to 24 VAC, 10 VA Class 2 Transformer |
| Water feed connection | 1/4 in. O.D. copper tubing with compression fitting |
| Drain hose connection | 1/2 in. I.D. flexible tubing to floor drain or pump |
| Water supply temperature | Cold or service hot water (hot water recommended for heat pump applications) |
| Certifications | UL rated, AHRI Guideline F compliant |
Before you buy
- Requires an existing or field-cut 14-3/4 in. by 14-5/16 in. opening on the warm air supply plenum or cold air return duct with 6-inch bypass ductwork connecting the opposing plenum.
- The Model 62 Automatic Digital Control must be mounted on the cold air return duct at least 6 inches upstream of the bypass duct entry to sense representative indoor air humidity.
- The outdoor temperature sensor must be installed on an exterior north- or east-facing wall out of direct sunlight using standard 18/2 low-voltage wire.
- A continuous downward pitch must be maintained on the 1/2-inch drain line to ensure free gravitational discharge and prevent winter freeze hazards.
- Annual replacement of the HydroCore™ cartridge is recommended prior to each winter heating season to sustain peak evaporative efficiency.
Questions about plenum sizing or digital control integration? Contact our technical team for assistance.
Frequently asked questions
What is the HydroCore water panel and how does it work?
The 620A features the HydroCore water panel (Model 35 replacement) engineered with an aluminum mesh honeycomb core and proprietary porous ceramic coating that distributes water evenly across the entire surface for optimal evaporative efficiency.
What automatic control is included with the 620A?
The 620A comes equipped with the AprilAire Model 62 automatic digital humidistat featuring an outdoor temperature sensor that automatically adjusts indoor humidity levels to prevent window condensation during cold weather.
Can the 620A be installed on either supply or return ductwork?
Yes. The unit can be mounted on either the warm air supply plenum or the cold air return drop with a 6-inch round bypass duct connecting to the opposite side.
What electrical connection is required for the solenoid valve?
The unit includes a 24 V AC electric water solenoid valve powered by the included 120 V to 24 V step-down transformer connected to the furnace board.
What water supply line connects to the humidifier?
Connect a 1/4-inch O.D. copper or braided stainless steel tubing line to the cold or hot water domestic supply pipe using the included shutoff valve.
Does the 620A have an integrated bypass damper?
Yes. The unit features an integrated circular bypass damper knob with clear Summer (closed) and Winter (open) positions, eliminating the need for an external manual pipe damper.
What drain line size is required?
A 1/2-inch I.D. flexible drain hose must be routed from the bottom drain spud with continuous downward pitch to an open basement floor drain, laundry sink, or condensate pump.
How often should the Model 35 water panel be replaced?
Replace the Model 35 water panel once per heating season (annually in the fall) to maintain maximum evaporation and prevent lime and mineral blockage.
Can hot domestic water be used to supply the humidifier?
Yes. Supplying the unit with domestic hot water increases evaporative capacity and is recommended on heat pump systems where duct air temperatures are cooler.
Documents
- AprilAire 620 Series Humidifier Engineering Specification Sheet (PDF)
- AprilAire Canada All Products Specification Reference Guide (PDF)
- AprilAire 620 & 720 Series Humidifier Owner's Manual (PDF)
Specifications compiled from official AprilAire 620 Series Engineering Specification Sheet (Lit. No. 406) and 620/720 Series Owner's Manual (10020114). All specifications subject to manufacturer verification. View AprilAire 620 specifications (PDF).
Installation & Safety Notice: Evaporative humidifiers require proper mounting to forced-air HVAC ductwork, plumbing connection to a potable water line, and 24V control wiring. Professional installation by a qualified HVAC technician is recommended.
Common questions
Is installation included?
No. AVL Shop sells equipment only. Installation is done by an independent licensed contractor that you hire.
How is freight charged?
Freight cost is included in your written quote before you pay.
What warranty does this product have?
The manufacturer warranty applies. Where we have the manufacturer’s exact wording, it is shown in the Warranty row of the specifications on this page, with a link to the source.
How do I get a quote?
Use Request a quote on this page and send the model and your city or postal code.