HEALTHY CLIMATE · LENNOX HUMIDIFIERSThe Healthy Climate space at AirGreenThe Healthy Climate humidifiers we sell, figures from Lennox’s documents, installed by AirGreen in Montréal, Laval, Longueuil, the South Shore and the North Shore.

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Healthy Climate humidifiers by Lennox · Updated October 20, 2026

Healthy Climate: bypass or fan-powered, it all comes down to the plenum

Lennox makes three sizes of whole-home humidifier: 12 and 17 US gal/day bypass, 18 US gal/day fan-powered, with a manual humidistat or an automatic control. The right model depends on your home, your furnace and what sits around the plenum.

Find my model See the models

12 · 17 · 18US gal/day, three sizes

2,100 sq ftlargest model, average home

5 yearscovered components (Lennox)

Once a yearat least: pad to replace

Bypass (HCWB3): warm furnace air flows through the pad and back to the return through a 6 in. duct. 24 V, 3 gal/h water feed. Lennox suggests it for smaller homes.

AirGreen × HEALTHY CLIMATELennox whole-home humidifiers12 · 17 · 18 US gal/dayBypass or fan-powered5 years on covered components (Lennox)Sold and installed by AirGreenMontréal · Laval · Longueuil · South Shore · North Shore

01 · The range

Three sizes, two ways to move the air

Each size comes with a manual humidistat or with the automatic “A” control. The HCWB3-12K is the Canadian version shipped with its installation kit.

7 models

HCWB3-12Bypass

Output: 12 US gal/day
Average home: 1,500 sq ft
Control: Manual humidistat
Pad: X2660

HCWB3-12ABypass

Output: 12 US gal/day
Average home: 1,500 sq ft
Control: Automatic (outdoor sensor)
Pad: X2660

HCWB3-12KBypass

Output: 12 US gal/day
Average home: 1,500 sq ft
Control: Manual humidistat
Pad: X2660

Installation kit included (Canada)

HCWB3-17Bypass

Output: 17 US gal/day
Average home: 2,000 sq ft
Control: Manual humidistat
Pad: X2661

HCWB3-17ABypass

Output: 17 US gal/day
Average home: 2,000 sq ft
Control: Automatic (outdoor sensor)
Pad: X2661

HCWP3-18Fan-powered

Output: 18 US gal/day
Average home: 2,100 sq ft
Control: Manual humidistat
Pad: X2661

HCWP3-18AFan-powered

Output: 18 US gal/day
Average home: 2,100 sq ft
Control: Automatic (outdoor sensor)
Pad: X2661

Reading the model number: HCWB3 = bypass, HCWP3 = power (fan); 12, 17 or 18 = US gallons per day; A = automatic control with outdoor sensor; K = installation kit included, sold in Canada only (6 in. flex duct and collar, drain tubing, water tubing, wire).

02 · The chooser

Bypass or fan-powered: seven questions, Lennox’s figures

The figures in the result come from Lennox’s documents; the pick between the two is our reading, confirmed on site. What can only be seen in person (space, outlet, drain) is checked at your home.

Heated area: 1,600 sq ft

Your home

Heating

Furnace airflow

Room for a 6 in. duct between supply and return

120 V outlet on a separate circuit near the furnace

Control

Our reading of Lennox’s sheets

HCWB3-17 · Bypass

17 US gal/day · Manual humidistat

See the product

Lennox coverage for an average home (8 ft ceilings): 2,000 sq ft for the HCWB3-17, your home: 1,600 sq ft.
Bypass: 6 in. duct to the return, 24 V (0.5 A), 3 gal/h water feed at 50 psi while it humidifies (water that does not evaporate goes to the drain). It runs when the furnace blower runs.
Upflow or horizontal furnace: Lennox mounts it on the supply.

Also possible: HCWP3-18 (fan-powered, 2,100 sq ft).

AirGreen × HEALTHY CLIMATE

Lennox’s humidifier, AirGreen’s installation.

Healthy Climate offers two ways to humidify through the furnace, and Lennox publishes what each model covers. AirGreen looks at what sits around your plenum and installs it.

What Healthy Climate brings

Two setupsBypass on 24 V (12 and 17 US gal/day) or fan-powered on 120 V (18 US gal/day).
Published coverageThree figures per model by how airtight the home is, for 8, 9 and 10 ft ceilings.
An automatic controlThe “A” versions lower the humidity setting when it is cold outside.
5 years on covered componentsLennox limited warranty, as Lennox writes it.

What AirGreen brings

Sold and installed by AirGreenIn Montréal, Laval, Longueuil, the South Shore and the North Shore.
Free in-home estimateWe look at the plenum, the outlet, the water and the drain on site.
Price on quotationFor the humidifier and its installation.
RBQ 5645-9605-01Subclasses 15.8, 15.10 and 16.

The result: the right Healthy Climate humidifier for your home and furnace, chosen with you and installed by AirGreen.

Find my model Book my free estimate

03 · Coverage

The same unit covers twice the area… or half

Lennox lists three areas per model for each ceiling height (8, 9 and 10 ft); we show the 8 ft figures. It all depends on how much air leaks out of the home, and higher ceilings mean less area covered.

HCWB3-12

1,500 sq ft

HCWB3-17

2,000 sq ft

HCWP3-18

2,100 sq ft

Average home: 15 to 20 years old (1 air change per hour, per Lennox). It is the figure shown on our product pages.

Area covered according to Lennox, 8 ft ceilings
Model	US gal/day	Tight	Average	Loose
HCWB3-12	12	3,000	1,500	750
HCWB3-17	17	4,000	2,000	1,000
HCWP3-18	18	4,200	2,100	1,050

Output rated by Lennox with 120 °F (49 °C) plenum air; Lennox publishes no figure for a heat pump’s cooler air, and then calls for hot water.

04 · Humidity level

The colder it is outside, the lower the humidity

The Healthy Climate owner’s manual gives one setting per outdoor temperature. The automatic “A” control adjusts on its own, by 0.5% per degree Fahrenheit.

Outdoor temperature

30%relative humidity Lennox recommends when it is −12 °C (+10 °F) outside

Below −10 °C, the INSPQ (citing CMHC) suggests 30%, or even 25%. Both sources agree: the colder it is, the lower you set it.

Health Canada recommends keeping humidity between 30 and 50% and acting as soon as condensation appears. In deep cold, Lennox goes below 30% to avoid condensation on windows. Sources: Lennox manual 506368-01 (temperatures converted from °F, rounded), Health Canada, INSPQ.

05 · Installation

What is needed around the furnace

The requirements from Lennox’s installation instructions, side by side.

Bypass · HCWB3

9½ × 9½ in. (12) or 10 × 12¾ in. (17) opening in the plenum.
6 in. bypass duct with a summer / winter damper.
On the supply (upflow or horizontal furnace) or on the return (downflow).
24 V, 0.5 A; transformer, saddle valve and damper supplied (17).
Humidifies only while the furnace blower runs; at most 0.4 in. w.c. between supply and return (17).
3 gal/h water feed at 50 psi while humidifying; water that does not evaporate goes to the drain.

Fan-powered · HCWP3

14 5/16 × 14¾ in. opening in the plenum.
No bypass duct: its fan pushes air through the pad.
On the supply; on the return only with hot water (120 °F continuous, 140 °F intermittent). Ruled out on a duct with horizontal airflow.
3-prong 120 V outlet, 0.8 A, on a circuit separate from the furnace motor.
The manual requires the furnace blower to run while it humidifies.
6 gal/h water feed at 50 psi while humidifying; water that does not evaporate goes to the drain.

Water, for both

Cold or hot, softened or not, up to 125 psi, plus a drain with a continuous slope. With a heat pump, Lennox calls for hot water (140 °F max.): the HCWB3-17 instructions require it and the owner’s manual recommends it for every model.

The “K” kit (Canada)

6 in. flex duct (3 ft) and collar, 15 ft of drain tubing, 10 ft of water tubing, 10 ft of 24 V wire, clamps and fittings. In our store: HCWB3-12K.

06 · Upkeep and warranty

A pad at least once a year, 5 years on covered components

X2660

HCWB3-12 pad

Replace at least once a year, says Lennox.

X2661

HCWB3-17 and HCWP3-18 pad

Same pad for the two larger models. Set the bypass damper to “summer” when you stop humidifying.

5 years

Lennox limited warranty

“5-Year Limited Warranty on covered components” on Lennox’s HCWB and HCWP pages. Lennox says no registration is required for its basic warranty.

What the Lennox certificate we could read says (W-021-L2, units installed before February 8, 2022): parts only, 5 years residential and 1 year otherwise; pad, filters and cabinet excluded; labour and diagnosis not covered; lack of maintenance voids the warranty. We could not find the certificate for newer installs online: the exact terms are those of the Lennox certificate for your unit.

07 · Rebates

No rebate found for a humidifier

Checked on October 20, 2026 on each program’s own site.

LogisVertNo

Guide v1.10 of September 15, 2026: heat pumps and other listed equipment, no humidifier.

RénoclimatNo

No humidifier among eligible measures (mechanical systems: HRV/ERV, drain-water heat recovery).

ÉnergirNo

No humidifier among the residential grants found (smart thermostat).

HiloNo

Compatible thermostats and controllers only.

ENERGY STARNo

A category for dehumidifiers, none for humidifiers.

Federal programsNo

Greener Homes: closed. Oil to Heat Pump: applications closed July 31, 2026, no humidifier.

Lennox Canada promotionsNo

Offers from September 14 to December 4, 2026: humidifiers are not included.

08 · Healthy Climate

Lennox’s indoor air quality line

Healthy Climate is the name Lennox gives its indoor air quality products: PureAir purifiers, filters, UV lights, humidifiers, dehumidifiers and ventilation. The humidifiers we sell are the HCWB3 and HCWP3 models.

Lennox International was founded in 1895 in Marshalltown, Iowa; its head office is in Richardson, Texas, and it has been in Canada since 1946.

The Lennox pageLennox heat pumps, central systems and VRF Healthy Climate humidifiersThe collection by type All our humidifiersSteam, bypass and fan-powered, every brand

09 · FAQ

The questions we get

Bypass or fan-powered: what is the difference?

The bypass model (HCWB3) uses the furnace’s pressure: warm air goes through the pad and back to the return through a 6 in. duct. The fan-powered model (HCWP3) has its own fan and needs no bypass duct, but it needs a 120 V outlet and a 6 gal/h water feed instead of 3.

Does it work with a central heat pump?

Yes, on a central forced-air system. Lennox then calls for hot water (140 °F max.): the HCWB3-17 instructions require it and the owner’s manual recommends it for every model. Lennox publishes no output figure with a heat pump’s cooler air.

How large an area does each model cover?

For an average home with 8 ft ceilings: 1,500 sq ft (HCWB3-12), 2,000 sq ft (HCWB3-17) and 2,100 sq ft (HCWP3-18). Lennox doubles these for a tight home and halves them for a loose one.

What do the A and the K mean?

A: automatic duct-mounted control, with an outdoor sensor that lowers the setting when it is cold. K: installation kit included (duct, collar, tubing, wire), sold in Canada only, on bypass models.

How much water does it use?

These are flow-through humidifiers: while humidifying, Lennox lists a water feed of 3 gal/h (HCWB3) or 6 gal/h (HCWP3) at 50 psi; the water that does not evaporate goes to the drain. A nearby drain is needed.

How often is the pad replaced?

At least once a year, says Lennox: X2660 for the HCWB3-12, X2661 for the HCWB3-17 and the HCWP3-18. The pad is excluded under certificate W-021-L2.

What setting should I use in winter?

Lennox’s manual goes from 45% at +4 °C down to 15% at −29 °C. Condensation or frost on the inside of windows usually means the level is too high: turn it down.

Does the fan-powered model run without the furnace?

It has its own fan, but Lennox’s owner’s manual requires the furnace blower to run while it humidifies: it stays connected to and controlled with the forced-air system.

What is the warranty?

Lennox advertises a 5-year limited warranty on covered components, with no registration required for its basic warranty. Under certificate W-021-L2 (installed before February 8, 2022), the pad is excluded and labour is not covered.

Is there a rebate for a humidifier?

We found none: LogisVert, Rénoclimat, Énergir, Hilo and the federal programs do not list humidifiers, and ENERGY STAR has no category for them (checked October 20, 2026).

Is softened water needed?

No: Lennox accepts cold or hot water, softened or not, up to 125 psi. With a heat pump, Lennox calls for hot water.

Is Healthy Climate made by Lennox?

Yes. Healthy Climate is Lennox’s indoor air quality line; the sheets, manuals and warranties for these humidifiers are Lennox documents.

No question matches. Write or call us.

Quotation

We look at your furnace, then we pick the model

The space around the plenum, the outlet, the water and the drain decide between bypass and fan-powered. Tell us what you have and request a free quote.

Request a free quote 514 316-2973

Office: 4951 Sainte-Catherine St. East, Montréal
Showroom: 1370 Joliot-Curie St., unit 712, Boucherville
Hours: Mon–Thu 8 a.m.–6 p.m., Fri 8 a.m.–4 p.m.
Email: sales@airgreen.ca
RBQ licence: 5645-9605-01 (subclasses 15.8, 15.10 and 16)

Sources checked October 20, 2026