Series 800 Steam Humidifier

Aprilaire Model 800 Whole-House Steam Humidifier for Homes Up to 6,200 Square Feet

The Aprilaire Model 800 is a whole-house steam humidifier engineered to deliver optimal humidity control in homes up to 6,200 square feet, including installations where traditional evaporative humidifiers fall short. This steam humidifier runs independently of your HVAC system, making it ideal for homes with crawl spaces, attics, non-forced air heating, or milder winter climates. With output capacities ranging from 11.5 to 34.6 gallons per day (depending on electrical configuration), the Model 800 produces pure steam that distributes evenly throughout your ductwork. The system features an automatic digital control for precision humidity management and uses a replaceable canister design for simple, low-maintenance operation.

Key Features & Benefits

• Independent Operation: This humidifier operates without relying on your furnace blower, allowing installation in crawl spaces, attics, and homes with non-forced air heating systems. You gain flexible placement options and year-round humidity control regardless of your heating setup.

• High Capacity Coverage: Delivers between 11.5 and 34.6 gallons of moisture per day depending on voltage (120V, 208V, or 240V at 16 amps), covering homes up to 6,200 square feet. This capacity range ensures proper humidity levels even in larger residences.

• Automatic Digital Humidifier Control: Includes precision automatic humidity control that continuously monitors and adjusts output to maintain your target humidity level. This removes guesswork and delivers consistent comfort without manual intervention.

• Replaceable Steam Canister: The user-replaceable canister contains all mineral buildup from water evaporation, eliminating complex cleaning routines. Maintenance consists solely of periodic canister replacement, making upkeep straightforward.

• Multiple Voltage Configurations: Available in 120V, 208V, and 240V configurations at 16 amps, providing installation flexibility to match your home's electrical service. Higher voltage options deliver greater output capacity for larger homes.

• Works with Cold Water: Operates using standard cold water supply (hard, soft, or softened water accepted), requiring no hot water connection. This simplifies installation and reduces plumbing requirements.

• Quiet Steam Generation: Produces steam silently within the canister unit, maintaining a peaceful home environment during operation. Only the water fill and drain valve actuation produce audible sounds.

• Manual Mode Option: Can be installed in manual control mode as an alternative to automatic operation, giving homeowners flexibility based on their preference and system integration needs.

Compatibility & Requirements

The Aprilaire 800 requires a dedicated electrical circuit at 120V, 208V, or 240V (16 amps) and a cold water supply line with 1/4 inch O.D. connection. The unit includes a 6-foot steam hose for flexible duct connection placement. Installation requires an available drain for the flush/drain cycle and sufficient clearance for the humidifier housing and canister access. The system works with round or rectangular ductwork using the included dispersion tube assembly or optional mounting brackets for specific duct configurations.

Installation & Care

Professional installation is recommended due to electrical and plumbing connections required. The humidifier mounts independently near ductwork, with the steam hose directing output into the supply plenum or duct. Maintenance involves periodic replacement of the steam canister (Aprilaire Model 80) as mineral deposits accumulate, with replacement frequency depending on water hardness and usage. The automatic flush cycle after each steam generation period helps extend canister life by removing mineral buildup.

What's Included

• Aprilaire Model 800 steam humidifier unit
• Automatic digital humidifier control
• 6-foot steam hose with clamps
• Drain hose kit
• Water inlet fill valve with feed tube and clamps
• Steam dispersion tube assembly
• Installation hardware and mounting components

Warranty & Support

The Aprilaire Model 800 is covered by Aprilaire's limited warranty as detailed in the included warranty documentation. Specific warranty terms, coverage periods, and conditions are outlined in the warranty policy document provided with the unit.

Frequently Asked Questions

Q: What are the common problems with AprilAire steam humidifiers?

A: The most frequently reported operational issue involves noise from the water fill and drain valves, which can produce audible clicking or banging sounds (water hammer) when solenoids open and close during fill and flush cycles. Some installations may also experience gurgling sounds transmitted through ductwork during the drain cycle. Installing inline water hammer arrestors on the supply line can reduce valve noise in many cases. The replaceable canister design addresses the other common maintenance concern by isolating mineral buildup in a user-serviceable component rather than requiring complex cleaning of internal elements.

Q: What is the benefit of AprilAire 800 steam humidifier?

A: The primary health benefit is maintaining optimal home humidity levels (typically 35 to 45 percent relative humidity), which has been shown to reduce the incidence of respiratory infections and minimize symptoms related to allergies and asthma by limiting the formation and survival of bacteria and viruses. Additional benefits include protection for wood floors, furniture, and musical instruments from damage caused by dry air, reduced static electricity, and improved overall comfort during heating seasons. The independent operation allows the unit to provide these benefits regardless of whether your heating system is actively running.

Q: How often should you replace the canister on an AprilAire 800?

A: Canister replacement frequency depends primarily on your water hardness and humidifier usage intensity. In areas with very hard water and continuous winter operation, replacement may be needed annually. Homes with softened or naturally soft water may extend canister life to two or more years. The humidifier will display a service indicator when mineral buildup reduces performance, signaling time for canister replacement (Aprilaire Model 80). Regular inspection during the heating season allows you to monitor canister condition and plan replacement before output drops significantly.

Q: How long is the steam hose on the AprilAire 800?

A: The included steam hose measures 6 feet in length. This provides flexibility for positioning the humidifier unit relative to your ductwork connection point while maintaining proper steam delivery into the supply plenum or duct. The hose connects to the steam outlet on the humidifier and terminates at the dispersion tube assembly that mounts into the ductwork.

Q: Can the Aprilaire 800 be installed in a crawl space or attic?

A: Yes, the Model 800 is specifically designed to accommodate installations in crawl spaces, attics, and other locations where traditional evaporative humidifiers are impractical. Because it operates independently of your HVAC blower, it does not require mounting on the furnace plenum. The unit does require protection from freezing temperatures for the water supply line and drain, but the crawl space itself does not need to be heated as long as supply and drain lines are protected. This makes it suitable for regions with milder winters and for homes with non-forced air heating systems.

Q: What electrical service does the Aprilaire 800 require?

A: The humidifier requires a dedicated 16-amp electrical circuit and is available in three voltage configurations: 120V, 208V, or 240V. The voltage selection determines maximum output capacity, with 120V providing 11.5 gallons per day, 208V providing 20.5 gallons per day, and 240V delivering up to 34.6 gallons per day. All configurations draw 16 amps and require proper circuit protection and wiring per local electrical codes. Professional installation ensures correct voltage matching and safe electrical connection.

Q: Does the Aprilaire 800 work with hard water or does it require a water softener?

A: The Model 800 operates with hard, soft, or softened water using a standard cold water supply. Hard water will accelerate mineral accumulation in the steam canister, requiring more frequent canister replacement, but does not prevent operation or damage the unit. Softened water extends canister service life by reducing mineral deposits. The replaceable canister design means mineral buildup is isolated in a maintenance component rather than affecting internal humidifier components.

Q: What replacement parts does the Aprilaire 800 require for regular maintenance?

A: The primary maintenance item is the Aprilaire Model 80 steam canister, which requires periodic replacement as minerals accumulate. Additional serviceable components include the water inlet fill valve assembly, drain valve, and steam hose, though these typically last for years under normal operation. The control board and solenoid valves are replaceable if electrical components fail. The automatic flush cycle that runs after each humidification period helps extend canister life by clearing some mineral deposits during operation.

Q: Can the Aprilaire 800 operate when the furnace is not running?

A: Yes, one of the key design features is independent operation that does not depend on furnace blower activity. The humidifier generates steam and relies on natural air circulation and pressure differentials within the duct system to distribute moisture. This makes it effective for homes with heat pumps, electric baseboard heat, radiant floor heating, or other non-forced air systems where traditional flow-through humidifiers cannot function. It also allows humidity control during mild weather when heating demand is minimal.

Q: What is included in the Aprilaire 800 installation kit?

A: The complete unit includes the steam humidifier housing with integrated control electronics, the automatic digital humidifier control, a 6-foot steam hose with mounting clamps, the water inlet fill valve with feed tube and clamps, the drain hose kit, and the steam dispersion tube assembly for duct mounting. Installation hardware and detailed installation instructions are provided. Additional components such as the drain trap assembly (Model 4028) for installations where the humidifier sits above the duct entry point, and mounting brackets for specific duct sizes, are available separately as needed for your particular installation configuration.