---
product_id: 557463062
title: "Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr"
brand: "aprilaire"
price: "$1341"
currency: NZD
in_stock: true
reviews_count: 5
category: "Aprilaire"
url: https://www.desertcart.nz/products/557463062-aprilaire-400-humidifier-24v-drainless-whole-house-humidifier-w-auto
store_origin: NZ
region: New Zealand
---

# 24V auto digital control Covers up to 5000 sq ft 17 gallons/day max output Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr

**Brand:** aprilaire
**Price:** $1341
**Availability:** ✅ In Stock

## Summary

> 💧 Elevate your air, elevate your lifestyle—because dry is so last season.

## Quick Answers

- **What is this?** Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr by aprilaire
- **How much does it cost?** $1341 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.nz](https://www.desertcart.nz/products/557463062-aprilaire-400-humidifier-24v-drainless-whole-house-humidifier-w-auto)

## Best For

- aprilaire enthusiasts

## Why This Product

- Trusted aprilaire brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Made in the USA:** Crafted by the original innovators of whole-home humidification—trusted quality and reliability.
- • **Drainless Design:** Forget messy maintenance with a drainless system that keeps your home clean and comfortable.
- • **Smart Auto Control:** 24V digital touch control adapts humidity levels automatically for optimal air quality.
- • **Whole-Home Hydration:** Effortlessly humidifies up to 5000 sq ft—perfect for your entire living space.
- • **Water-Wise Technology:** Unique evaporative process ensures 100% water efficiency—no waste, just pure comfort.

## Overview

The Aprilaire 400 is a powerful, drainless whole-house humidifier designed to cover up to 5000 square feet with a maximum output of 17 gallons per day. Featuring a 24V automatic digital control, it uses an innovative evaporative process that conserves water by evaporating 100% of the water supplied. Made in the USA by the pioneers of whole-home humidification, this unit ensures consistent, efficient humidity control to protect your skin, wood floors, and overall indoor air quality.

## Description

Product Information:About the Aprilaire 400 24V WholeHouse Drainless Humidifier with Automatic Digital ControlAre you tired of dry skin, splitting or cracking on your hard wood floors or trouble breat

Review: I spent a lot of time deciding on a humidifier. I checked humidity levels all over the house and they were pretty consistent at 23-25% at 25-30 degrees outside. My home is 3000 sf and the specs for this model put that size at its limit. I was debating between the 600 and this model, the 400. Ultimately, I picked this model for its efficient water usage and after a lot of use I am positive I made the right choice. Unlike other humidifiers this one does not drain water unless there is a problem. Water still comes in from the top and flows over the water panel but water flow stops when a holding cup gets filled on the bottom. Other models just keep running water until there is no longer a call for humidity by the humidistat. The water in the cup is then wicked up and then water flow turns on again, This happens over and over as needed. Installation was pretty straight forward. It took $36 worth of parts at the hardware store and about 3 hours to get it installed. Tape the supplied outline on either the supply (make sure it's above the AC Coil) or the return duct and cut a hole. Find a spot for the bypass (a 6" round duct) on the other duct and make a hole there. The unit mounts the the duct with several screws (self taping sheet metal screws make fast work) and two screws for the 6" duct coming off of it. Just a tip - if the unit can be mounted with the first section of duct attached then screw it on before mounting it. I had a little trouble getting a drill in there once it was mounted to the furnace. I used metal tape on the edges of the unit itself and all the duct joints. I used two adjustable elbows and a short section of flex duct to make the connection between the unit and the bypass. Now for the water. I did more research on this than I care to admit. Here's what I kept reading, if the furnace does not have long run cycles then run hot water to the humidifier. They explained it that if the furnace doesn't get hot for a long time then the humidifier will not work as efficient. So, with that logic I ran hot water to it. The kit includes a saddle valve which makes for an easy install. Unfortunately these aren't the greatest so I put in a different valve. This took more time than anything else. Once the valve was in, I ran the shortest possible length of tubing to the humidifier in an attempt to keep the incoming hot water as hot as possible. After running the humidifier for some time now, my opinion is the hot water makes no difference. The water flow doesn't run enough to keep it hot for very long. I found that water will run for maybe 1 minute max before the fill cup fills and shuts off the water. After a couple minutes the cup will empty and water will run again, but this time for even less time because the water panel is already wet. The heat from the furnace, even on a short run time, seems to do just fine. Next was the wiring. Turn off power to the furnace to avoid frying the board. I tapped into an existing 24VAC line for the power, connected the C (common) and H (humidifier) from the furnace board, the white and yellow from the humidifier and the outside temp sensor wires to the humidistat. I mounted the humidistat before the humidifier on the cold air return. The humidistat will work in automatic mode based on outside temperature. I found this a little conservative for my home. When in manual mode I can maintain over 40% humidity without a problem. I usually don't keep it this high but wanted to see if it could do it. I took the same humidity readings as prior and have a reading within 3% throughout the house.
Review: Let me start off by saying I installed this myself, and I am a technician by profession, so it may have been easier for me than for some people. It did not seem very complicated to me though, and the directions included appear very clear and straightforward. I think anyone with some basic tools and mechanically inclined could do this themselves, otherwise you might want to hire a professional installer. The kit included everything I needed except sheet metal screws and tubing (1/4" copper for water supply, 1/2 clear vinyl for drain), and some additional 14-20 AWG wire nuts. I also bought an additional T-fitting with 1/4 turn shut off valve to hook up the water supply in my 1/2" copper hot water pipe. I don't recommend using the saddle valve they provide in the kit for the piping, as they frequently fail, and do not meet code. I mounted the unit on the return manifold, and used a couple of 90° 6" elbows and a few feet of flexible HVAC hose for the bypass duct, and sealed it all with the silver foil HVAC tape. As for the functionality of the unit, it's working great so far. I really like the water saving feature on it. It comes with a composite material filter (paper/metal screen) and a tray with float sensors to shut off the water valve if it gets full. This makes for a much more economical use of water in my opinion, and still has an overflow drain tube in case of malfunction. I like the outdoor temperature sensor to use the automatic feature for humidity adjustment, and it also has a feature to turn on the furnace blower to circulate and humidify the air if the humidity level is too low, separate from the thermostat control, which is very nice. Both features work perfectly so far, and my relative humidity went up 10% after the first day. This is the most precise and full control featured humidifier I saw at this price point, and was a very good value for the money.

## Features

- BUY WITH CONFIDENCE This humidifier was designed and manufactured in the USA by AprilAire – the inventor of the whole home evaporative humidifier and the leader in indoor air quality solutions
- FULL COVERAGE up to 5000 square feet in tightly built homes with a capacity of 17 gallons per day
- CONSERVES WATER using a unique process that evaporates 100% of the water flowing into the water panel

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B004PDDZRS |
| Auto Shutoff | Yes |
| Brand | Aprilaire |
| Capacity | 17 G/day |
| Color | White |
| Customer Reviews | 4.4 4.4 out of 5 stars (294) |
| Date First Available | 7 August 2012 |
| Item Weight | 3.99 Kilograms |
| Material | Wood |
| Model Number | 400Z |
| Product Dimensions | 26.04 x 39.07 x 40.01 cm; 3.99 kg |
| Runtime | 37 hours |
| Special Features | evaporative |
| Voltage | 24 Volts (AC) |

## Product Details

- **Brand:** Aprilaire
- **Capacity:** 17 G/day
- **Colour:** White
- **Floor area:** 4000 Square Feet
- **Special features:** evaporative

## Images

![Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr - Image 1](https://m.media-amazon.com/images/I/713QElbV4GL.jpg)
![Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr - Image 2](https://m.media-amazon.com/images/I/51sE1GWJhML.jpg)
![Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr - Image 3](https://m.media-amazon.com/images/I/71jYVlDaKFL.jpg)
![Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr - Image 4](https://m.media-amazon.com/images/I/71Z5g9di6sL.jpg)
![Aprilaire 400 Humidifier, 24V Drainless Whole House Humidifier w/Auto Digital Control .7 Gallons/hr - Image 5](https://m.media-amazon.com/images/I/71syfOrti0L.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Review
*by B***N on 8 February 2014*

I spent a lot of time deciding on a humidifier. I checked humidity levels all over the house and they were pretty consistent at 23-25% at 25-30 degrees outside. My home is 3000 sf and the specs for this model put that size at its limit. I was debating between the 600 and this model, the 400. Ultimately, I picked this model for its efficient water usage and after a lot of use I am positive I made the right choice. Unlike other humidifiers this one does not drain water unless there is a problem. Water still comes in from the top and flows over the water panel but water flow stops when a holding cup gets filled on the bottom. Other models just keep running water until there is no longer a call for humidity by the humidistat. The water in the cup is then wicked up and then water flow turns on again, This happens over and over as needed. Installation was pretty straight forward. It took $36 worth of parts at the hardware store and about 3 hours to get it installed. Tape the supplied outline on either the supply (make sure it's above the AC Coil) or the return duct and cut a hole. Find a spot for the bypass (a 6" round duct) on the other duct and make a hole there. The unit mounts the the duct with several screws (self taping sheet metal screws make fast work) and two screws for the 6" duct coming off of it. Just a tip - if the unit can be mounted with the first section of duct attached then screw it on before mounting it. I had a little trouble getting a drill in there once it was mounted to the furnace. I used metal tape on the edges of the unit itself and all the duct joints. I used two adjustable elbows and a short section of flex duct to make the connection between the unit and the bypass. Now for the water. I did more research on this than I care to admit. Here's what I kept reading, if the furnace does not have long run cycles then run hot water to the humidifier. They explained it that if the furnace doesn't get hot for a long time then the humidifier will not work as efficient. So, with that logic I ran hot water to it. The kit includes a saddle valve which makes for an easy install. Unfortunately these aren't the greatest so I put in a different valve. This took more time than anything else. Once the valve was in, I ran the shortest possible length of tubing to the humidifier in an attempt to keep the incoming hot water as hot as possible. After running the humidifier for some time now, my opinion is the hot water makes no difference. The water flow doesn't run enough to keep it hot for very long. I found that water will run for maybe 1 minute max before the fill cup fills and shuts off the water. After a couple minutes the cup will empty and water will run again, but this time for even less time because the water panel is already wet. The heat from the furnace, even on a short run time, seems to do just fine. Next was the wiring. Turn off power to the furnace to avoid frying the board. I tapped into an existing 24VAC line for the power, connected the C (common) and H (humidifier) from the furnace board, the white and yellow from the humidifier and the outside temp sensor wires to the humidistat. I mounted the humidistat before the humidifier on the cold air return. The humidistat will work in automatic mode based on outside temperature. I found this a little conservative for my home. When in manual mode I can maintain over 40% humidity without a problem. I usually don't keep it this high but wanted to see if it could do it. I took the same humidity readings as prior and have a reading within 3% throughout the house.

### ⭐⭐⭐⭐⭐ Review
*by A***3 on 15 December 2019*

Let me start off by saying I installed this myself, and I am a technician by profession, so it may have been easier for me than for some people. It did not seem very complicated to me though, and the directions included appear very clear and straightforward. I think anyone with some basic tools and mechanically inclined could do this themselves, otherwise you might want to hire a professional installer. The kit included everything I needed except sheet metal screws and tubing (1/4" copper for water supply, 1/2 clear vinyl for drain), and some additional 14-20 AWG wire nuts. I also bought an additional T-fitting with 1/4 turn shut off valve to hook up the water supply in my 1/2" copper hot water pipe. I don't recommend using the saddle valve they provide in the kit for the piping, as they frequently fail, and do not meet code. I mounted the unit on the return manifold, and used a couple of 90° 6" elbows and a few feet of flexible HVAC hose for the bypass duct, and sealed it all with the silver foil HVAC tape. As for the functionality of the unit, it's working great so far. I really like the water saving feature on it. It comes with a composite material filter (paper/metal screen) and a tray with float sensors to shut off the water valve if it gets full. This makes for a much more economical use of water in my opinion, and still has an overflow drain tube in case of malfunction. I like the outdoor temperature sensor to use the automatic feature for humidity adjustment, and it also has a feature to turn on the furnace blower to circulate and humidify the air if the humidity level is too low, separate from the thermostat control, which is very nice. Both features work perfectly so far, and my relative humidity went up 10% after the first day. This is the most precise and full control featured humidifier I saw at this price point, and was a very good value for the money.

### ⭐⭐⭐⭐ Review
*by A***N on 21 January 2026*

I bought the AprilAire 400 specifically because my basement doesn't have a floor drain near the furnace. The best part about this unit is that it uses a float system to evaporate all the water, so it doesn't dump anything out of a drain line. It saved me the huge hassle and extra cost of having to buy and install a condensate pump. The installation went okay, but the instructions weren't the best. They get the job done, but they aren't the best or most clear. I had to Google a few things to make sure I had it all installed correctly. Overall, it’s a solid humidifier that actually works. If you're in a spot where you can't easily run a drain line, this is definitely the one to get. It’s kept my house much more comfortable this winter without any leaks or mess. This can be installed without the outdoor temperature sensor installed, you have to flip a switch in the controller to manual mode. I plan to install the sensor next summer as it's too cold outside to work on a project like that. Overall works great for my application and brought my indoor humidity from 5-10% up to 35% where I set it at.

## Frequently Bought Together

- AprilAire 400 Whole-House Humidifier, Automatic Water Saver Furnace Humidifier, Large Capacity Whole-House Humidifier for Homes up to 5,000 Sq. Ft., White
- AprilAire 5844 Humidifier Installation Kit for AprilAire Whole Home Humidifiers with Automatic Control, Compatible with AprilAire Humidifier Models: 400, 500, 600 Black

---

## Why Shop on Desertcart?

- 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016
- 🌍 **Shop Globally** — Access 737+ million products across 21 categories
- 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price
- 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members)
- 🔒 **Secure Payments** — Trusted payment options with buyer protection
- ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews

**Shop now:** [https://www.desertcart.nz/products/557463062-aprilaire-400-humidifier-24v-drainless-whole-house-humidifier-w-auto](https://www.desertcart.nz/products/557463062-aprilaire-400-humidifier-24v-drainless-whole-house-humidifier-w-auto)

---

*Product available on Desertcart New Zealand*
*Store origin: NZ*
*Last updated: 2026-02-17*