Product Price Humidifier Capacity (gpd) Coverage Area (sq ft) Humidistat Included Auto Shutoff Water Tank Capacity (gal) Energy Efficiency Rating
AprilAire Model 500MK Whole-House Humidifier
US
£144.98 12 3000

The AprilAire Model 500MK is a small bypass flow-through whole-house humidifier with a 12-gallon-per-day output and manual humidistat. It is designed for tightly constructed homes up to 3,000 square feet and includes an installation kit.

★ Ideal for

This model suits shoppers seeking the whole-house humidifier with the largest capacity because its 12-gallon-per-day output provides substantial moisture delivery for homes up to 3,000 square feet.

AprilAire 800Z Whole-House Steam Humidifier
US
£814.23 11.5 to 34.6 10300

The AprilAire 800Z is a high-capacity whole-house steam humidifier that delivers up to 34.6 gallons of moisture per day and covers homes up to 10,300 square feet. It includes a digital automatic humidistat, dual-sensor control, and a replaceable steam canister, making it suitable for large homes and spaces with demanding humidity needs.

★ Ideal for

This product suits the question because its output reaches 34.6 gallons per day and its rated coverage extends up to 10,300 square feet, making it a high-capacity whole-house option.

AprilAire Model 500 Whole-House Humidifier
US
£218.76 12 3600

The AprilAire Model 500 is a bypass whole-house evaporative humidifier that delivers 12 gallons of moisture per day and covers homes up to 3,600 square feet. It includes an automatic digital humidistat and is best suited for smaller to mid-sized homes with ducted HVAC systems.

★ Ideal for

It suits shoppers asking which whole-house humidifier has the largest capacity because its 12 gallons-per-day output supports whole-home humidification for up to 3,600 square feet.

AIRCARE Space Saver Whole-House Humidifier
US
£111.23 8.5 2700 6

The AIRCARE Space Saver is an evaporative whole-house humidifier that covers up to 2,700 square feet and delivers up to 8.5 gallons of moisture per day. Its six-gallon reservoir, adjustable humidistat, digital controls, refill indicator, and casters make it well suited to large homes and multiple rooms.

★ Ideal for

This model is a strong choice for seeking a whole-house humidifier with the largest capacity because it combines an 8.5-gallon daily output with a six-gallon water reservoir and coverage up to 2,700 square feet.

AprilAire Model 865
US
£1104.93 34.6 6200

The AprilAire Model 865 is a high-output whole-house steam humidifier that produces up to 34.6 gallons of moisture per day and includes a digital manual humidistat and wall-mounted fan pack. It suits large homes, very dry climates, and homes without ductwork, with straightforward canister-based maintenance.

★ Ideal for

This model is well suited to the question because its 34.6 gallons-per-day output is exceptionally large and it can cover up to 6200 square feet, making it a strong choice for high-capacity whole-house humidification.

AprilAire Model 700MKH
US
£363.36 18 5300

The AprilAire Model 700MKH is a fan-powered whole-house evaporative humidifier that delivers 18 gallons of moisture per day and covers homes up to 5,300 square feet. It includes a manual humidistat and installation kit, making it suitable for larger homes with forced-air HVAC systems.

★ Ideal for

This model suits the question because its 18-gallon-per-day capacity is among the largest for whole-house evaporative humidifiers, with coverage up to 5,300 square feet.

AprilAire Model 400M
US
£219.50 17 5000

The AprilAire Model 400M is a water-saving whole-house bypass evaporative humidifier rated at 17 gallons per day for homes up to 5,000 square feet. It includes a manual humidistat and safety shutoff features, making it suitable for homeowners with ducted HVAC systems who want high output with minimal water waste.

★ Ideal for

It suits buyers seeking high capacity because it delivers 17 gallons per day and covers up to 5,000 square feet, although it is not the highest-capacity whole-house humidifier available.

AprilAire Model 800 Whole-House Steam Humidifier
US
£814.23 34.6 10300 Not Energy Star compliant

The AprilAire Model 800 is a high-capacity whole-house steam humidifier that can deliver up to 34.6 gallons of moisture per day and cover homes up to 10300 square feet. It includes a digital automatic humidistat and suits large homes, arid climates, and spaces with demanding humidity requirements.

★ Ideal for

This product specifically suits the question because its capacity reaches 34.6 gallons per day and its coverage extends up to 10300 square feet, making it one of the largest-capacity whole-house humidifiers.