# AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel

AprilAire 4788 is a whole-house humidifier maintenance kit for AprilAire models 400, 400A, and 400M. It combines a No. 45 water panel with replacement maintenance components, so it is intended for a broader service refresh than a filter-only replacement.

- [Original product page](https://best-deals.pro/product/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [View offer](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- Market: US
- Language: en-US
- Currency: USD
- Brand: Aprilaire
- Model: 4788
- Category: Home & Kitchen > Appliance Parts & Accessories > Air & HVAC Filters
- Price: 116.99 USD
- Previous price: 137.99 USD
- Discount: 15%
- Price checked: 2026-11-12T09:59:30.050Z
- Rating: 4.7 / 5
- Reviews: 110

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## At a glance

- The listing identifies compatibility with AprilAire whole-house humidifier models 400, 400A, and 400M.
- The claimed kit components include a No. 45 water panel and several water-distribution and float-related parts.
- The listing recommends replacing the water panel twice during the season.

## Pros

- Includes components beyond the water panel, which may suit scheduled maintenance when several listed parts are due for replacement.
- The listed compatible models make it easier to distinguish this kit from AprilAire kits intended for other humidifier models.

## Specifications

### Identity
- Brand listed: Research Products Corporation
- Model: 4788
### Compatibility and dimensions
- Listed humidifier models: 400, 400A, 400M
- Water panel dimensions: 12.875" H x 9.875" L x 1.75" W
- Product dimensions listed: 1.75 x 9.88 x 12.88 inches
- Weight listed: 0.01 ounces

## Before you buy

- The listing recommends replacing the water panel twice during the season. Consult the humidifier owner's manual before maintenance. The stated 40%–60% humidity range and associated health benefits are manufacturer claims, not independently verified outcomes.

## In the box

- Water Panel \(45\) (Check selected pack)
- Scale Control Insert \(4403\) (Check selected pack)
- Water Distribution Tray \(4407\) (Check selected pack)
- Feed Tube with Compression Sleeve and Nut \(4335\) (Check selected pack)
- Yellow Orifice \(4231\) (Check selected pack)
- In-line Strainer \(4004\) (Check selected pack)
- Float Assemblies \(4406\) (Check selected pack)
- Float Cover \(4405\) (Check selected pack)
- Owner's Manual (Check selected pack)

## A good fit for

- Owners maintaining an AprilAire 400, 400A, or 400M whole-house humidifier who want the listed water panel and service parts together.

## Less suited to

- Owners of other humidifier models unless their model's documentation confirms compatibility.
- Buyers who need only a replacement water panel and do not need the other listed maintenance components.

## Customer feedback

Customer feedback highlights OEM quality and fit. The listing also identifies specific compatible models, so those fit reports are most relevant when the buyer's humidifier is a 400, 400A, or 400M. Aggregate ratings are largely five-star, but ratings alone do not establish fit for every installation.
- Positive themes: Customers describe the kit as an OEM product that fits well.

## Frequently asked questions

### Which humidifier models is the AprilAire 4788 listed for?
The listing names AprilAire whole-house humidifier models 400, 400A, and 400M.
### What parts does the kit listing name?
It names a Water Panel \(45\), Scale Control Insert \(4403\), Water Distribution Tray \(4407\), Feed Tube with Compression Sleeve and Nut \(4335\), Yellow Orifice \(4231\), In-line Strainer \(4004\), Float Assemblies \(4406\), Float Cover \(4405\), and Owner's Manual.
### How often does the listing recommend replacing the water panel?
It recommends replacing the water panel twice during the season. Follow the humidifier owner's manual for maintenance instructions.

## Alternative options

- [AprilAire 35 Water Panel Humidifier Filter Replacement for AprilAire Whole-House Humidifier Models 300, 350, 360, 560, 560A, 568, 600, 600A, 600M, 700, 700A, 700M, 760, 760A, 768 \(Pack of 2\)](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 10 Water Panel Humidifier Filter Replacement for AprilAire Whole-House Humidifier Models 110, 220, 500, 500A, 500M, 550, 550A, 558 \(Pack of 2\)](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [TOMOON 45 Water Panel Humidifier Filter Fit for April.aire 400 400A 400M \| 45 Water Panel Humidifier Filter Compatible with April.aire 400 400A 400M Humidifier, 9-7/8" x 12-7/8" x 1.75", 2 Pack](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 4750 Humidifier Maintenance Kit with Water Panel Model No. 35 Humidifier Replacement Filter for AprilAire Whole-House Humidifier Models: 700, 700A, 700M, 760, 760A, 768](https://best-deals.pro/visit/aprilaire-4750-humidifier-maintenance-kit-model-35)
- [AprilAire E130 Pro 130-Pint Whole-House Dehumidifier, Energy Star Certified, Commercial-Grade for Basement, Crawlspace or Whole House up to 7,200 sq. ft.](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 45 Water Panel Humidifier Filter Replacement for AprilAire Whole-House Humidifier Models 400, 400A, 400M \(Pack of 10\)](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 4839 Maintenance Kit with Water Panel Model No. 35 Replacement Filter for Whole-House Humidifier Models: 600, 600A, 600M](https://best-deals.pro/visit/aprilaire-4839-humidifier-maintenance-kit-model-35)
- [AprilAire H635EZ1 Humidifier Filter/Water Panel Assembly Replacement Kit for AprilAire Whole-House Humidifier Models: 600, 600A, and 600M](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire H735EZ1 Humidifier Filter/Water Panel Assembly Replacement Kit for AprilAire Whole-House Humidifier Models: 700, 700A, and 700M](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 10 Water Panel Humidifier Filter Replacement for AprilAire Whole-House Humidifier Models 110, 220, 500, 500A, 500M, 550, 550A, 558 \(Pack of 1\)](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 4793 Humidifier Maintenance Kit with Water Panel Model No. 10 Humidifier Replacement Filter for AprilAire Whole-House Humidifier Models: 550, 558](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [AprilAire 12 Water Panel Humidifier Filter Replacement for AprilAire Whole-House Humidifier Models 112, 224, 225, 440, 445, 445A, 448 \(Pack of 1\)](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)

## Add-ons

- [AprilAire 45 Water Panel Humidifier Filter Replacement for AprilAire Whole-House Humidifier Models 400, 400A, 400M \(Pack of 2\)](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)
- [Aprilaire Genuine OEM Water Level Sensor Assembly 4410 for Model: 400](https://best-deals.pro/visit/aprilaire-4788-humidifier-maintenance-kit-no-45-water-panel)

## Images

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 1](https://best-deals.pro/i/wrEHhVgJuzSBTLBYSB5FVykuKA-oVs_K2PokCjbp_Bj80Z8Qhr94vSr_d5uyscIKLDi5EZceVTlNpGyqUMeHOp5dBFIZKGENL5Q_XM6J3NCVnmG0iWBE.jpg)

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 2](https://best-deals.pro/i/2sxVzVuqA_5FDXImXFt0wkBsVm4iWs-aaxpykUi2jd6bamDZG5nYJLNaloo-uVdP3G4OWo7pr-r-J4kdvRvPUGsz58vHm_Jumy1dvm7D4v6PQAKF1z3s.jpg)

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 3](https://best-deals.pro/i/VEf9iWd3OjiqROG8TNgJmzcHBc8hILWP-EVC3KAa35gnDcKULfVhgx9il18_6oUOkk4lk0TvZQTjv6ZpzJHwfA0b0IoFWLcg_Igv-DHsXZJ9GcoUxkvx.jpg)

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 4](https://best-deals.pro/i/xmuCUNQDNL9CU9VtYTCz3IfAVRwtxo45LMdiw7v2KqfC3YYRG3cMmPUcN63BY1RvRxqv2ZMuuNxAKuBMwoQIOYBqXR2Zpgok7DgF2xrN7sxgl8IIlPL8.jpg)

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 5](https://best-deals.pro/i/y1L_s7Z8HWTUiYT2ePtw474hn8e5PeXTRxhYVHo7IHmnZsPK_jUFoQ_VZPxk3OsuRgZ1FwGkMEbLM6QF6LYMaYlVjJbsMnU0MgpwtyJbv9RMZWmM6BPM.jpg)

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 6](https://best-deals.pro/i/4R7WcIZG8-SCLSHsieG8OTlazL_mD_dEVR49Mxyzdg62mdcxEuxZrasNaPRgQ1-ro2tVED3GwoEsxjh0P_DaGob-Zb8p-AseKkgwgZ5SGgGe-gjSkJi9.jpg)

![AprilAire 4788 Humidifier Maintenance Kit with No. 45 Water Panel — 7](https://best-deals.pro/i/kh5P70V3hEneY6Orv6W7qSPaNMt_9eNHiIdHIDRc4_Eas9mspSN9KnvTkyL6Z1yIRneH_yZP9djIGUs7bKO1Tj6HXqMezlaYjmJWqywitJsAf4BrW3f2.jpg)