A high-capacity whole-house fan-powered evaporative humidifier engineered for direct supply plenum mounting without bypass ductwork. The AprilAire Model 700 delivers up to 18 gallons per day (GPD) of moisture distribution for homes up to 5,300 sq. ft. Built with an integrated quiet-operating circulating fan, the Model 700 draws heated air directly from the furnace or heat pump supply plenum through the internal water panel and injects humidified air directly into the home duct system. This self-powered airflow design eliminates the requirement for a separate 6-inch bypass duct, making it ideal for compact mechanical rooms, heat pump systems operating at lower plenum temperatures, and large residential floorplans. Equipped with the Model 60 Automatic Digital Humidifier Control and outdoor temperature sensor, the unit continuously modulates humidity to prevent window condensation while safeguarding architectural wood flooring and millwork during Canadian winter heating.
Technical specifications
| Warranty | 5 year warranty Source: AprilAire warrantyWarranty is provided by the manufacturer under its own terms. See the source link for full details. |
|---|
Key features
- Integrated internal circulating fan — built-in fan drives airflow through the water panel directly into supply ductwork without requiring bypass duct piping.
- Direct supply plenum installation — mounts directly to the warm air supply plenum, reducing installation space requirements in compact furnace mechanical rooms.
- High evaporative capacity — delivers 18 gallons per day, providing whole-home moisture coverage for expansive residential spaces up to 5,300 sq. ft.
- Automatic digital humidity control — includes Model 60 digital controller and outdoor temperature sensor to dynamically balance indoor moisture and avoid window condensation.
- Heat pump optimized performance — internal motorized fan delivers rated moisture output even on heat pump systems with lower plenum discharge air temperatures.
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 | 700 Series Fan-Powered Evaporative |
| Model / SKU | 700 |
| Equipment type | Whole-house fan-powered evaporative humidifier (no bypass duct) |
| 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) |
| Fan drive mechanism | Integrated internal circulating fan motor |
| Bypass duct requirement | None (self-powered airflow) |
| Humidifier control included | Model 60 Automatic Digital Humidifier Control |
| Outdoor temperature sensor | Included (digital proportional reset) |
| Replacement water panel | Model 35 Water Panel |
| Plenum opening dimensions | 14-7/8 in. W × 14-3/16 in. H (378 × 360 mm) |
| Unit dimensions | 15-29/32 in. W × 18 in. H × 10-11/32 in. D |
| Electrical rating (fan motor) | 120 VAC, 60 Hz, 0.8 A (plugs into standard 120V outlet or hardwires) |
| Electrical rating (control circuit) | 24 VAC, 60 Hz, 0.5 A (transformer included) |
| Transformer included | 120 VAC to 24 VAC, 10 VA Class 2 Transformer |
| Water feed rate | 3 Gallons Per Hour (GPH) |
| Water supply 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 14-7/8 in. by 14-3/16 in. opening on the warm air supply plenum where the internal circulating fan can discharge directly into circulating airflow.
- Requires an accessible 120 VAC grounded electrical outlet within 6 feet for the internal circulating fan motor power cord, or dedicated field wiring by a qualified electrician.
- The Model 60 Automatic Digital Control must be mounted on the cold air return duct to sample representative return air relative humidity.
- Install the outdoor temperature sensor on an exterior wall facing north or east out of direct sunlight using standard 18/2 low-voltage wire.
- Annual replacement of the Model 35 Water Panel is recommended prior to each heating season to ensure continuous rated 18 GPD output.
Questions about supply plenum installation or electrical connections? Contact our technical team for assistance.
Frequently asked questions
Where is the Model 700 mounted on the HVAC system?
The unit mounts directly to the warm air supply plenum, requiring only a single rectangular cutout (approx. 14.8 in. wide by 14.3 in. high) with zero bypass ductwork.
Which water panel does the Model 700 use?
The Model 700 uses the genuine AprilAire Model 35 evaporative water panel.
What electrical connection is required for the internal fan?
The internal circulation fan motor operates on 120 V AC single-phase 60 Hz power (0.8 A), plugging directly into a standard 120 V wall outlet, while the water solenoid valve is controlled via 24 V AC.
Does the Model 700 include an automatic digital controller?
Yes. The unit includes the Model 60 automatic digital humidistat with an outdoor temperature sensor that automatically adjusts humidity levels to avoid window sweating in winter.
What water supply line connects to the unit?
Connect a 1/4-inch O.D. copper or flexible line to the domestic hot or cold water pipe. Using domestic hot water provides highest evaporation rates.
What drain line size is required?
A 1/2-inch I.D. drain hose routes from the bottom drain spud to an open floor drain, laundry tub, or condensate pump.
Is there a summer/winter damper on the Model 700?
No. Because the Model 700 mounts directly to the supply duct without a bypass pipe, there is no bypass damper to open or close between seasons.
What is the annual maintenance procedure for the Model 700?
Unclip the front cover, replace the Model 35 water panel, clean any mineral deposits in the distribution tray and drain nozzle, and inspect the fan blade for dust.
Documents
- AprilAire 700 Series Whole-House Evaporative Humidifier Specification Sheet (PDF)
- AprilAire Canada All Products Specification Reference Guide (PDF)
- AprilAire Model 700 Humidifier Owner's Manual (PDF)
Specifications compiled from official AprilAire 700 Series Whole-House Evaporative Humidifier Specification Sheet (Lit. No. 383) and 700 Series Owner's Manual (B2209190). All specifications subject to manufacturer verification. View AprilAire 700 specifications (PDF).
Installation & Safety Notice: Fan-powered humidifiers require 120V power or 24V transformer wiring and proper supply-plenum mounting. Installation by a licensed 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.