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Aprilaire

Aprilaire 400
Water Saver Bypass Humidifier

Drainless whole-home bypass humidifier delivering 17 gallons per day. Uses 100% of the water that enters the system — no floor drain required. Perfect for homes with septic systems or no accessible drain.

No Drain Required
Annual Maintenance
Made in USA
Aprilaire 400 Water Saver Bypass Humidifier
Specifications

Aprilaire 400 at a Glance

Drainless bypass design that uses 100% of incoming water — ideal for homes with septic systems or where no floor drain is available.

17 GPD
Daily Capacity
0.7 GPH
Evaporation Rate
4,000 sq ft
Coverage (Tight Home)
Bypass
Humidifier Type
24V
Electrical
2×/yr
Water Panel Change
Model: Aprilaire 400  ·  15⅜″W × 15¾″H × 10¼″D  ·  Automatic Digital Control  ·  No Drain Required
How It Works

Zero-Waste Water Technology

1
Sensor Reads
The automatic digital control monitors indoor humidity and outdoor temperature, triggering the humidifier only when needed.
2
Water Recirculates
Water enters a reservoir and wicks upward through the Model 45 Water Panel. Excess water is captured and recirculated — nothing goes down the drain.
3
Air Absorbs
Dry air from the return duct passes through the moisture-laden Water Panel via the bypass damper, absorbing humidity naturally.
4
Whole-Home
Humidified air is distributed through your existing ductwork to every room — no portable units, no refilling, no wasted water.
Benefits

Why Choose the Aprilaire 400?

No Drain Required

The 400 uses 100% of the water that enters the system. No floor drain, no drain line, no standing water. Perfect for homes with septic systems or basements without a drain.

Water Conservation

While standard bypass humidifiers send excess water down the drain, the 400 recirculates and evaporates every drop. Minimal water usage saves on utility costs all season.

Set It & Forget It

Automatic digital control with outdoor temperature sensor adjusts humidity levels throughout the season — no manual tweaking required.

Healthier Air

Maintaining 40–60% relative humidity reduces airborne viruses, eases allergy and asthma symptoms, and prevents dry skin and bloody noses all winter.

Flexible Install

Mounts on supply or return plenum with right or left discharge. No bypass ductwork needed — the built-in damper keeps the install clean and compact.

Protects Your Home

Dry air cracks hardwood floors, splits furniture, peels wallpaper, and loosens joints. A whole-home humidifier prevents thousands in damage every winter.

Buyer Guide

Is the Aprilaire 400 Right
for Your Home?

You don't have a floor drain near your furnace
The 400 is the only Aprilaire bypass humidifier that operates without a drain. It uses 100% of the water — no drain line needed. Ideal for homes with septic systems or furnaces in locations without drain access.
Your home is under 4,000 sq ft
The 400 is rated for tightly constructed homes up to 4,000 sq ft, average-construction homes up to 2,000 sq ft, and loosely sealed homes up to 1,000 sq ft. For larger homes, consider the Aprilaire 600 or 620.
You want to conserve water
Standard bypass humidifiers send gallons of excess water down the drain daily. The 400's recirculation design uses every drop, saving hundreds of gallons per season.

Not sure which humidifier fits your home? Our technicians will assess your ductwork, home size, and climate needs — no charge.

Book a Free Assessment
Why H&C

The GTA's Trusted
Indoor Air Quality Experts

Licensed & Insured
Every technician is fully licensed and insured — we take pride in every job.
17+ Years Experience
Family-run business serving the GTA with integrity and expertise since 2008.
24/7 Emergency
We answer the phone 365 days a year. Your comfort is our priority.
5-Star Rated
Consistently rated 5 stars on Google by real GTA homeowners.
Free Home Assessment
We assess your home, measure humidity, and recommend the right unit — no pressure, no cost.
Aprilaire Authorized
Authorized Aprilaire dealer — professional install required for full warranty coverage.
FAQ

Humidifier
Questions, Answered.

Have a question that's not here? Call us — our technicians are happy to help.

1-855-539-4328
How does the Aprilaire 400 work without a drain?
The 400 uses a water recirculation system. Water enters a reservoir and wicks upward through the Model 45 Water Panel. As dry air passes over the panel, moisture evaporates into the airstream. Any water that isn't evaporated stays in the reservoir and is reused. The unit uses 100% of the water that enters it — no drain line is needed at all.
How does the 400 compare to the 500 and 600?
The 400 delivers 17 GPD — the same as the 600 and 5 GPD more than the 500. The key difference is the 400 requires no drain. The 500 and 600 are flow-through designs that require a floor drain or condensate pump. Choose the 400 if drain access is limited; choose the 600 if you have a drain and want a simpler water panel replacement schedule.
How often does the Water Panel need to be replaced?
The Model 45 Water Panel should be replaced twice per heating season for most homes. Because the 400 recirculates water rather than flushing it, mineral buildup occurs faster than in drain-through models. The digital control includes a service indicator. Two panels come included with the unit.
Can I connect it to hot or cold water?
Aprilaire recommends cold water for the Model 400. Because the wicking Water Panel design pulls water upward, hot water provides less benefit than it does in flow-through models. Cold water works well and keeps things simple. Avoid connecting to softened water if possible — softened water can accelerate mineral deposits on the panel.
Is it good for homes with heat pumps?
Yes — the Aprilaire 400 is an excellent choice for homes with heat pumps. Heat pumps produce lower plenum temperatures than gas furnaces, which reduces evaporation rates in standard humidifiers. The 400's water recirculation design helps compensate by keeping the Water Panel saturated longer. Connect to your hot water supply for the best performance with a heat pump.
What humidity level should I set?
The ideal range is 35–45% relative humidity in winter. The automatic digital control adjusts based on outdoor temperature — when it's very cold outside, it lowers the target slightly to prevent condensation on windows. Most GTA homeowners set the target around 40% and let the automatic control handle the rest.
What Homeowners Are Saying

Real Reviews from Real Customers

Michael Tomas
Google Review
★★★★★

"I had an excellent experience with Farshid at H&C. From the initial call and showing up to my place within 30 minutes to the completion of the service, their team was professional, responsive, and extremely knowledgeable. They arrived on time, explained the issue clearly, and walked me through the options without any pressure. The technicians were courteous, respectful of my home. I highly recommend H&C Heating and Cooling to anyone looking for dependable HVAC service. It's refreshing to work with a company that truly values customer satisfaction."

Verified Google Review
Minoo GM
Google Review
★★★★★

"Professional, timely and efficient service. I would highly recommend using this company. Exceeds expectation."

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Nikita Nikiff
Google Review
★★★★★

"Fantastic customer service and very reliable HVAC installation."

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Amit Dahan
Google Review
★★★★★

"Our technician, Cameron, was thorough- diagnosed and repaired the issue methodically, and explained the steps as he did the work. Highly recommended."

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Get Your Free
Humidifier Quote

Fill out the form — or call us directly at 1-855-539-4328. Our team will reach out within 2 hours with a free, no-obligation estimate.

Same-Day Quotes
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No Obligation
Free estimate with no hidden fees
Licensed Technicians
Required for Aprilaire warranty coverage