Home » GREE FLEXX ULTRA R32 Central Heat Pump (TTI Air Conditioning)
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R-32 · one outdoor unit per tonnage
GREE FLEXX ULTRA R32 · FXU model numbers · Updated Oct. 27, 2026

GREE FLEXX ULTRA R32 central heat pump. Four tonnages, four FXU outdoor units. Every size still delivers its full 8.3 °C rating at −15 °C.

4 FXU systems, from 2 to 5 tons. GREE’s FLEXX ULTRA R32 carries FXU model numbers: an outdoor unit made for each tonnage, paired with the air handler of the same size. That is what sets it apart from the GUD systems, where two tonnages share the same unit outside.

Compare FXU and GUDCheck my line setBook my free estimate
25,000 BTU/hCertified heat at −15 °C for the 2-ton FXU: its full 8.3 °C rating. The two other GREE 2-ton central systems AirGreen offers keep 24,000.
100%Of the 8.3 °C rating kept at −15 °C, at all four FXU sizes: 25,000, 34,000, 48,000 and 54,000 BTU/h, per NEEP.
21 AMCA of the FXU24, the 2-ton’s own outdoor unit, with 25 A protection. The GUD 2-tons share the 3-ton outdoor unit: 27.7 A and 30 A.
  • 4FXU systems on this page
  • 4FXU outdoor units, one per tonnage
  • 2–5tons
  • 4/4ENERGY STAR cold climate, checked on the certificate
AirGreen × GREEGREE Elite dealerOne FXU outdoor unit per tonnage100% of the rating at −15 °C, 2 to 5 tonsAHRI certificates 215213329 to 215213332Montréal, Laval, Longueuil, South Shore, North Shore
FXU or GUD

Same tonnage, different outdoor unit: what the FXU really changes.

The FXU and GUD certificates look a lot alike. The real gaps fit in a few lines, mostly at 2 tons, then at 4 and 5 tons. Here they are, without padding.

Your tonnage, what matters to you.

Pick a size, then a criterion. The answer puts the FXU next to the GUD systems of the same tonnage (E or G air handler), from their certificates and documents.

All three families by tonnageGUD + E pageUNIX R32 pageFXU on a furnace: FXA coil
The FXU documents

Certificates, brochures, manuals: what we keep from each.

They do not all say the same thing. When two of them disagree, this page shows both versions or sticks to the certificate.

DocumentStatusWhat we take from it
NEEP and ENERGY STARAHRI 215213329 to 215213332
Certified
Capacities, COP, SEER2, EER2 and HSPF2 on this page. ENERGY STAR files the four systems as “FLEXX High-efficiency Series”, cold climate.
GREE Comfort brochure 012226Current version, read Oct. 26, 2026
Current
31 ft pre-charged and 49 ft of rise, at every size.
GREE Comfort brochure 032725Attached to our product sheets
Superseded
25 ft pre-charged, 98 ft of rise (2 and 3 tons) and 49 ft (4 and 5 tons). The “Line sets” tool below accounts for both versions.
French brochure BRO0125Carries TTI Climatisation’s address
Ratings not used
Its efficiency and capacity figures differ from the certificates; we do not use them. Its warranty is quoted in the questions below.
French manuals posted by TTIAir handler and outdoor unit
Read
Minimum room area by charge, thermostat cable length, refrigerant sensor service life.
AirGreen × GREE

The right FXU for your house, and an installation that follows its documents.

GREE builds the FXU outdoor unit and its air handler. AirGreen calculates the tonnage, prepares both circuits and runs the line set within the printed limits.

GREE

What GREE brings

  • One outdoor unit per tonnageFXU24, FXU36, FXU48 and FXU60, each with the air handler of the same size.
  • GREE G20 compressorDouble cylinder, 2-stage inverter, per GREE Comfort.
  • Heating down to −30 °CThat is the −22 °F printed in GREE Comfort’s brochure, which also gives cooling from 5 °F to 129 °F.
AirGreen

What AirGreen brings

  • GREE Elite dealerGREE training completed, priority access to original parts.
  • Free estimateWe measure the air handler’s room and the route to the FXU outdoor unit, then calculate the tonnage.
  • RBQ 5645-9605-01Licences 15.8, 15.10 and 16. Gas and oil work is done by a licensed partner.

The result: an FXU at the tonnage your heat loss calls for, certified under its AHRI number, installed by a GREE Elite dealer.

Compare FXU and GUDBook my free estimate
The GREE shop

All 4 FXU systems, right below.

Each product sheet carries the system’s AHRI number (215213329 to 215213332), the FXU outdoor unit and its air handler.

GREE
Know before you buy

Cold, line sets, sound: the FXU size by size.

Three tools set to the four FXU systems, built from the certificates and GREE Comfort’s brochures: enough to come to the visit with the right questions.

What each FXU delivers, from 8.3 °C to −30 °C.

Pick a size. Bars: the rating, then the maximum capacities NEEP publishes for the system’s AHRI number. At −15 °C all four FXU systems reach their 8.3 °C rating.

The share kept at −30 °C, tonnage by tonnage, and the design temperatures for Montréal and Laval are on the GREE central heat pumps page.

Technician’s corner

For your electrician and installer: the FXU figures.

Two circuits

Outdoors: MCA 21 A and 25 A protection (FXU24), 27.7 A and 30 A (FXU36), 39.9 A and 45 A (FXU48), 40 A and 45 A (FXU60). Indoors: 4.7 to 7.7 A, 15 A protection, 24 VAC control.

GREE Comfort 032725

The charge

Factory R-32: 88.2 oz for the FXU24, 102.3 oz for the FXU36, 162.3 oz for the FXU48 and FXU60. Beyond the pre-charged length: 0.323 oz per foot (2 and 3 tons), 0.215 oz (4 and 5 tons).

GREE Comfort 032725

Airflow and lines

760, 1,000, 1,200 and 1,500 CFM from 2 to 5 tons. One pair of lines at every size: 3/8 in liquid, 3/4 in gas, flared connections.

GREE Comfort 032725

Outdoor footprint

FXU24 and FXU36: 39 × 37-13/16 × 14-9/16 in, 187.4 lb. FXU48 and FXU60: 35-7/16 × 49-5/8 × 13-3/8 in, 241.4 lb.

GREE Comfort 032725

Always powered

The outdoor manual posted by TTI asks that the unit stay powered at all times after installation, except during service: its leak detection depends on it.

FLEXX ULTRA R32 manual, TTI

FXU air handlers and their electric heating elements are on the GREE electric furnaces page.

Did you know?

Five FXU details you will not find on the product sheet. Flip the cards.

LogisVert · Hydro-Québec

LogisVert pays on the heat at −8 °C, not at −15 °C.

$2,4722-ton FXU, AHRI 215213329: 20,600 BTU/h at −8 °C. Its 25,000 BTU/h at −15 °C do not count in the formula.
$3,3843-ton FXU, AHRI 215213330: 28,200 BTU/h at −8 °C, for 34,000 at −15 °C.
$4,7404-ton FXU, AHRI 215213331: 39,500 BTU/h at −8 °C, for 48,000 at −15 °C.
$5,4005-ton FXU, AHRI 215213332: 45,000 BTU/h at −8 °C, for 54,000 at −15 °C.

At the cold-climate rate of $120 per 1,000 BTU/h, per Hydro-Québec’s list of Oct. 27, 2026; these amounts stay indicative until Hydro-Québec approves the claim. What is accepted or excluded for a central system: the GREE central heat pumps page.

Questions

What people ask us about the FLEXX ULTRA R32.

Is the FLEXX ULTRA R32 the same heat pump as GREE’s GUD central systems?
Not on paper. The FXU systems have their own model numbers, their own AHRI certificates (215213329 to 215213332) and a separate outdoor unit at every tonnage. Their certified values often match the GUD systems, except at 2 tons (25,000 BTU/h at −15 °C against 24,000) and at 4 and 5 tons (COP 3.4 at 8.3 °C against 3.36).
How much heat is left at −15 °C and −30 °C?
At −15 °C, NEEP rates every FXU at its full 8.3 °C rating: 25,000, 34,000, 48,000 and 54,000 BTU/h. At −30 °C the maximum drops to 18,000, 20,400, 26,200 and 27,000 BTU/h. Nothing is published in between, so nothing at −23 °C, Montréal’s design temperature. The calculation made at your home will tell whether electric backup heat is worth it.
Can I keep a regular thermostat?
Per a GREE Comfort tech tip, yes: the FLEXX R32 works with any standard 24-volt heat pump thermostat. The WK010 controller is only needed for RS485 communication, a proprietary GREE protocol. The indoor manual posted by TTI limits the thermostat communication cables to 30 m.
How much line set between the FXU outdoor unit and the air handler?
From 10 to 164 ft for the 2- and 3-ton, from 10 to 98 ft for the 4- and 5-ton, per GREE Comfort. Beyond the pre-charged length, 0.323 oz of R-32 is added per foot (2 and 3 tons) or 0.215 oz (4 and 5 tons). The brochure attached to our product sheets gives 25 ft pre-charged; its current version, 31 ft. The actual route is measured at the visit.
What warranty do the FXU documents print?
Two different answers. GREE Comfort’s US brochure, document 032725 attached to our product sheets: 5 years parts and 7 years compressor, residential and commercial. The French brochure BRO0125, which carries TTI Climatisation’s address: 10 years parts and compressor, residential. Before you sign, ask for the manufacturer’s written warranty for your unit: that is the one that counts.
Can the FXU air handler go in a small room?
R-32 is an A2L refrigerant: the air handler’s room needs a minimum floor area that depends on the charge. The manual posted by TTI asks for 7.4 m² for 2.5 kg (FXU24), 8.6 m² for 2.9 kg (FXU36) and 13.7 m² for 4.6 kg (FXU48 and FXU60). A long line set adds charge, so area: we measure the room at the visit.
AirGreen

Four FXU sizes, only one right for your house: we pick it by calculation.

Free estimate at home. Montréal, Laval, Longueuil, South Shore and North Shore.

Contact us514-316-2973
GREE Elite dealerGREE training completed, priority access to original parts.
RBQ 5645-9605-01Licences 15.8, 15.10 and 16.
AHRI on every product pageThis page shows a LogisVert amount only when it matches Hydro-Québec’s list of Oct. 27, 2026.
Sources

Capacities and amounts: indicative, to be confirmed in the quote. Tool calculations: AirGreen, from the published values above. Page updated Oct. 27, 2026; NEEP records, ENERGY STAR and the LogisVert list checked again that day.