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LG · Multi F MAX · Six-ZoneThe LG six-room multi-zone at AirGreenSold and installed by AirGreen across Montreal, Laval, Longueuil, the South Shore and the North Shore.
Check my six headsLG · 6-room multi-zone · updated October 27, 2026
LG six-zone heat pump: the Six-Zone and its six 15 m branches
At six rooms the KUMXA361A is no longer enough. The smallest LG unit that takes them is the 42,000 BTU/h KUMXA421A, LG’s Six-Zone and the only unit capped at six heads. On the piping side, six 15 m branches add up to exactly the 90 m LG allows for all branches together.
The six-room plate
Six heads, five numbers
- R-32 units allowed
- 5 of 13
- LG Six-Zone
- KUMXA421A
- Six 15 m branches
- 90 m, LG’s limit
- Six 12,000 heads
- KUMXB541A KUMXB601A
- Indicative LogisVert
- $1,690 to $4,200
Sources: LG R-32 combination manuals, KUMXA421A and KUMXB601A spec sheets, NEEP, read October 14, 2026; Hydro-Québec LogisVert list of October 27, 2026.
The Six-Zone
Six rooms: the KUMXA421A, or a 54,000 unit or larger for six 12,000s
The KUMXA361A stops at five heads. At six, five R-32 units remain, and head size decides which one.
KUMXA421A, LG’s Six-Zone
56,000BTU/h of heads at most, from 18,000 at least
$3,792indicative LogisVert, Cold Climate certified
This Multi F MAX with LGRED° keeps heating down to −25°C. LG measures its certified rating (AHRI 215402347) with six 16.4 ft branches behind a 16.4 ft main line, 114.8 ft of piping in all: a six-room setup.
Six 12,000 heads: 72,000
That is more than the ceiling of the KUMXA421A (56,000) and of the 48,000 units (65,000). Only the KUMXB541A, capped at 73,000, and the KUMXB601A, at 81,000, take them.
On a 48,000, three 12,000s and three 9,000s make 63,000. On the KUMXA421A a 12,000 only fits if another head drops to 7,000: 12,000 + 9,000 × 4 + 7,000 = 55,000.
Pairing
Six heads: where a 12,000 fits
The tool starts from the KUMXA421A with one 12,000, four 9,000s and one 7,000, or 55,000. Change the unit or a head to see the total move.
Total connected: 55,000 BTU/h
This combination fits LG’s range of 18,000 BTU/h to 56,000 BTU/h.
Indicative LogisVert: $3,792
Connected capacity ranges and largest wall head with 6 heads: LG R-32 combination data manuals (PDFs dated January 15, 2026). With 6 heads, the tool checks neither exclusions by head type nor the capacity per distribution-box port: we confirm those on the quote.
| Unit (LG ceiling) | All at 9,000 | All at 12,000 | Largest head, the rest at 7,000 |
|---|---|---|---|
| KUMXA421A, ceiling 56,000 | 54,000 · yes | no; a 12,000 needs a 7,000 (55,000) | 18,000 (53,000); the 24,000 gives 59,000 · no |
| 48,000 units, ceiling 65,000 | 54,000 · yes | 72,000 · no; 12,000 × 3 + 9,000 × 3 = 63,000 | 24,000 (59,000) · yes |
| KUMXB541A, KUMXB601A, ceiling 73,000 and 81,000 | 54,000 · yes | 72,000 · yes | 24,000 · yes |
Piping
Six 15 m branches: right on the limit
Six branches, 90 m in total
15 m15 m15 m15 m15 m15 m
090 m · 295.3 ft
On a Multi F MAX, each branch, from the distribution box to the head, runs 5 to 15 m (16.4 to 49.2 ft), and all branches together stay within 90 m (295.3 ft). Six 15 m branches make 295.2 ft: every one can go to the maximum, with no margin left. At seven heads that is no longer possible.
Two boxes, six ports
As with five rooms, you need two distribution boxes joined by the ARBLN03321 Y-branch. The six heads take six ports, for example a 4-port and a 2-port box (PMBD3640ZR and PMBD3620ZR), or two 3-port boxes (PMBD3630ZR).
Piping limits: LG spec sheets for the KUMXA361A and KUMXB601A (2026).
Every unit for six rooms
Five R-32 Multi F MAX units take six heads
Three standard and two LGRED° units. Only the KUMXB481A is in our 6-zone collection; the KUMXA421A, KUMXA481A, KUMXB541A and KUMXB601A have a six-head product page online, also shown on the Multizones page.
Multi F MAX
Heats down to −20°C · 3 units
This collection
Four listings, one LogisVert amount
In the 6-zone collection, as of October 27, 2026, the KUMXB481A is the only listed unit, at $1,690. The LMU420HHV, the collection’s only LGRED unit, has no NEEP, ENERGY STAR or Hydro-Québec record.
$1,690KUMXB481A, the collection’s only listed unit
$3,792KUMXA421A, Cold Climate Six-Zone, outside the collection
$1,690 to $4,200the five LG units allowed with six heads
| Outdoor unit | Refrigerant | LG family | Max. heads (LG) | LogisVert |
|---|---|---|---|---|
| KUMXB481A | R-32 | Multi F MAX | 8 | $1,690 |
| LMU420HHV | R-410A | Multi F MAX with LGRED | not confirmed | not on the list |
| LMU480HV | R-410A | not confirmed | not confirmed | not on the list |
| LMU600HV | R-410A | not confirmed | not confirmed | not on the list |
For the LMU420HHV, only LG’s LGRED page mentions “up to 6 zones”, for the range rather than this model. The KUMXB481A, titled “Multi F” in the store, is a Multi F MAX according to LG.
No six-room LG multi-zone project is published in our gallery yet.
See our LG projectsFrequently asked questions
What people ask us most
What is the smallest LG unit for six rooms?
The 42,000 BTU/h KUMXA421A, LG’s Six-Zone. Its six heads can add up to 18,000 to 56,000 BTU/h: six 9,000s make 54,000. Indicative LogisVert amount: $3,792.
Which LG unit takes six 12,000 BTU/h heads?
They add up to 72,000, so you need the KUMXB541A, capped at 73,000, or the KUMXB601A, at 81,000. With 9,000s to fill in, a 48,000 unit takes three 12,000s at most (63,000).
Can every head be 15 m from its distribution box?
With six heads, yes, just: LG limits each branch to 15 m and all branches to 90 m, and 6 × 15 m = 90 m. From seven heads up, the average has to come down.
Does the 6-zone collection include a certified LGRED unit?
No. The LMU420HHV has no NEEP, ENERGY STAR or LogisVert record. The Cold Climate certified KUMXA421A has its six-head product page outside this collection, and we can offer it on the quote.
AirGreen · Air conditioning & heating
Six rooms on one LG unit, branches measured and boxes laid out, planned with you and installed by AirGreen.
We come see your home, choose the series and size with you, and hand you a clear quote with the AHRI number and the indicative LogisVert amount when the unit qualifies.
Hydro-Québec does not solicit anyone by phone or door to door for LogisVert. If a call “from Hydro-Québec” offers you a heat pump, hang up.
RBQ 5645-9605-01Subclasses 15.8, 15.10 and 16
Free estimateAt home, no obligation
LogisVert checkedBy AHRI number, in Hydro-Québec’s tool
Showroom1370 Joliot-Curie Street, Suite 712, Boucherville
Sources checked
- LG Electronics U.S.A., R32 Multi F and Multi F MAX Outdoor Unit Combination Data Manual and … with LGRED° … (files 05_25, PDFs dated January 15, 2026): head counts, connected capacity ranges, allowed heads.
- LG Electronics U.S.A., R-32 spec sheets KUMXA361A, KUMXA421A and KUMXB601A (2026): distribution boxes, Y-branch, piping limits, branch count of the reference rating.
- NEEP ccASHP list and ENERGY STAR Certified Air-Source Heat Pumps (dataset w7cv-9xjt), read October 14, 2026.
- Hydro-Québec, LogisVert list of October 27, 2026 and participation guide version 1.10 (September 15, 2026).
- AirGreen, airgreen.ca product pages and collections, October 27, 2026.
LogisVert amounts are indicative: Hydro-Québec confirms them when you apply. The program rules and LG’s warranty are explained once, on the LG page. Prices on quote.
The LG six-room shop
The LG six-head systems we sell.
Each product page gives the outdoor unit, its six heads and its AHRI number. Each one’s LogisVert status is in the collection table above.
