GeneralAire GF4200DMM Humidifier | Installation in Montreal, Laval, Longueuil, South Shore and North Shore
Is it the right size for your home?
It puts 17 gallons of water a day into the air (with 49 °C (120 °F) furnace air), enough to humidify about 2,000 sq ft (our estimate). Pick your home's living area.
It's the right size.
For a 900 to 1,500 sq ft house, it's within its range. It will run at part load on ordinary days and keep a reserve for the coldest days.
AirGreen estimate. GeneralAire advertises 'up to 4,200 sq ft' without saying how tight the house is. For an average-construction home, we count 120 sq ft per gallon a day, the ratio in AprilAire's and Lennox's tables. Older or leaky house: go one size up; our estimator confirms it on site.
What it does, in numbers
Output: manufacturer's spec (17 gal/day, with 49 °C (120 °F) furnace air).
What you should know about this one
Published, verifiable figures, not brochure claims.
17 galWhat it produces per day, at full output
About 64 litres of water turned into humidity in 24 hours. The control runs it to match the humidity you set: it rarely runs flat out, except in very cold weather.
Heat pumpBehind a heat pump, it produces less
It evaporates water from a pad using the heat of the air coming off the furnace. A heat pump blows cooler air, so it evaporates less. With a heat pump, talk to our estimator: depending on the manufacturer, we connect it to hot water or suggest a steam model instead.
12 in.17 gal/day in a 12 in. cabinet
It delivers 17 gal/day from a 12 in. wide cabinet, with a 9⅛ × 12 in. opening. Bypass and solenoid valve on the left or right.
PEXPEX tubing and shut-off valve included
It comes with ¼ in. PEX tubing (hot or cold water) and a ½ in. push-on valve with shut-off instead of a saddle valve.
Cooler airBuilt for cooler plenums
GeneralAire presents it as designed for lower plenum temperatures. With cooler air it still produces less than its rating.
ControlThe control that comes with it
GeneralAire MHX3 manual humidistat.
UpkeepWhat gets replaced, and when
GF-GA35 Vapor Pad, replace at the start of each heating season.
35%The humidity to aim for in winter, at most
At −7 °C, no more than 35%; at −18 °C, no more than 25%. Above that, the moisture condenses on the windows. The control adjusts for you if it has an outdoor sensor.
5 yearsThe manufacturer's warranty, and what it covers
5 years on the solenoid valve only. We register the warranty in your name at start-up.
What it needs on site
Our estimator checks the ducts, the water supply and the drain before ordering.
Complete spec sheetData and cited sources
- Brand
- GeneralAire
- Model
- GF4200DMM
- Type
- Bypass
- Output
- 17 US gal/day (with 49 °C (120 °F) furnace air)
- Water to drain
- About 3.5 gal/h while running
- Control included
- GeneralAire MHX3 manual humidistat.
- Upkeep
- GF-GA35 Vapor Pad, replace at the start of each heating season.
- Living area
- 2,000 sq ft (AirGreen estimate)
- Dimensions (L × D × H)
- 12 × 8.5 × 15 in
- Power supply
- 24 V
- Weight
- 8 lb
- Warranty
- 5 years on the solenoid valve only.
Output, dimensions, electrical data and warranty: GeneralAire manufacturer's data. Living area: AirGreen estimate, explained under « Your home ».
The next model down and up
Talk to an HVAC technician before you choose
We look at your heating system, the electrical panel, the water supply and the drain, and give you an installed price.
GeneralAire GF4200DMM: 17 gal/day in a 12 in. wide cabinet
The GF4200DMM is a bypass humidifier that delivers 17 gal/day with 49 °C (120 °F) furnace air. It suits a home of about 2,000 sq ft by our estimate. It keeps the width of the GF3200DMM, but its cabinet is taller.
More output, small footprint
It delivers 17 gal/day from a 12 in. wide cabinet, with a 9⅛ × 12 in. opening. GeneralAire presents it as designed for lower plenum temperatures. With cooler air, it still produces less than its rating. Like the GF3200DMM, it comes with ¼ in. PEX tubing and a ½ in. valve with shut-off.
On the job and every fall
It mounts on the supply or return plenum, with a 6 in. bypass duct. A drain takes the water that doesn't evaporate. The MHX3 manual humidistat is supplied. The GF-GA35 pad is changed at the start of each heating season. The 5-year warranty covers the solenoid valve only. Behind a heat pump, the air stays cool and a steam model gives a more predictable result.
To get a quote
Call AirGreen at 514 316-2973. Our estimator comes to check the heating system, the electrical panel, the water and the drain, then gives you a quote for the installed unit. We work in Montréal, Laval, Longueuil, the South Shore and the North Shore.