![Amazon.com: Aprilaire 400M Whole Home Humidifier with Manual Control + Bypass Humidifier Installation Kit, Water Saver Furnace Humidifier, Large Capacity Whole House Humidifier for Homes up to 4,000 Sq. Ft. : Appliances Amazon.com: Aprilaire 400M Whole Home Humidifier with Manual Control + Bypass Humidifier Installation Kit, Water Saver Furnace Humidifier, Large Capacity Whole House Humidifier for Homes up to 4,000 Sq. Ft. : Appliances](https://m.media-amazon.com/images/I/71hfZXSB8XL._AC_UF894,1000_QL80_.jpg)
Amazon.com: Aprilaire 400M Whole Home Humidifier with Manual Control + Bypass Humidifier Installation Kit, Water Saver Furnace Humidifier, Large Capacity Whole House Humidifier for Homes up to 4,000 Sq. Ft. : Appliances
![The house I bought has an old furnace with this Aprilaire unit attached. I see it's a humidifier, but as far as I can tell its main purpose is to let AC The house I bought has an old furnace with this Aprilaire unit attached. I see it's a humidifier, but as far as I can tell its main purpose is to let AC](https://preview.redd.it/c6254pc7mpq71.jpg?width=640&crop=smart&auto=webp&s=befff76a2e7e7420e0260bfdf4fd2b195ec8502f)
The house I bought has an old furnace with this Aprilaire unit attached. I see it's a humidifier, but as far as I can tell its main purpose is to let AC
![AprilAire 600 Whole-House Humidifier, Automatic High Output Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 5,000 Sq. Ft., White: Amazon.com: Industrial & Scientific AprilAire 600 Whole-House Humidifier, Automatic High Output Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 5,000 Sq. Ft., White: Amazon.com: Industrial & Scientific](https://m.media-amazon.com/images/I/61q6PtyYpYL.jpg)
AprilAire 600 Whole-House Humidifier, Automatic High Output Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 5,000 Sq. Ft., White: Amazon.com: Industrial & Scientific
![Amazon.com: AprilAire 500M Whole-House Humidifier, Manual Compact Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 3,600 Sq. Ft., White : Home & Kitchen Amazon.com: AprilAire 500M Whole-House Humidifier, Manual Compact Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 3,600 Sq. Ft., White : Home & Kitchen](https://m.media-amazon.com/images/I/61B1zAJfUjL._AC_UF1000,1000_QL80_.jpg)
Amazon.com: AprilAire 500M Whole-House Humidifier, Manual Compact Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 3,600 Sq. Ft., White : Home & Kitchen
![AprilAire 600 Whole-House Humidifier - Automatic - Large Capacity Water Saver Furnace Humidifier for Homes up to 4,000 Sq. Ft. - Walmart.com AprilAire 600 Whole-House Humidifier - Automatic - Large Capacity Water Saver Furnace Humidifier for Homes up to 4,000 Sq. Ft. - Walmart.com](https://i5.walmartimages.com/asr/ef3b86dc-254a-49d2-ad6f-e5e007673e93.aafd0ba18477aa53aeeb9f5f01df9757.jpeg?odnHeight=768&odnWidth=768&odnBg=FFFFFF)
AprilAire 600 Whole-House Humidifier - Automatic - Large Capacity Water Saver Furnace Humidifier for Homes up to 4,000 Sq. Ft. - Walmart.com
![Amazon.com: Aprilaire 500M Whole Home Humidifier with Manual Control + Bypass Humidifier Installation Kit, Compact Furnace Humidifier, Large Capacity Whole House Humidifier for Homes up to 3,000 Sq. Ft. : Appliances Amazon.com: Aprilaire 500M Whole Home Humidifier with Manual Control + Bypass Humidifier Installation Kit, Compact Furnace Humidifier, Large Capacity Whole House Humidifier for Homes up to 3,000 Sq. Ft. : Appliances](https://m.media-amazon.com/images/I/71MS+TpMgXL._AC_UF894,1000_QL80_.jpg)