Home / Comparisons / 2-zone multi-zone heat pumps
LG Multi F LGRED 18,000 and SAMSUNG FJM Premium 20,000 in 2 zones, number by number
Two rated sizes, 18,000 and 20,000 BTU, for two systems with two 9,000 BTU wall heads. AirGreen offers both as 2-zone options in these lines. The labels differ, but in extreme cold the certified capacities converge: 22,000 BTU/h each at −15 °C, 17,830 and 18,000 BTU/h at −25 °C.
LGMulti F LGRED R32, 2 zones
KUMXA181A + 2 heads of 9,000 BTU · AHRI 214848473
See the product page
SAMSUNGFJM Premium, 2 zones
AJ020DXS3CG + 2 × AJ009DNADCG · AHRI 216372795
See the product pageWhat the electricity costs, in dollars, winter and summer
AirGreen estimate for the same 18,000 BTU/h zone in Montréal, at Hydro-Québec rate D, taxes included. The two systems do not have the same rated size; the calculation gives them exactly the same zone to heat and cool. Both heat pumps are calculated in exactly the same way, with the same method as on all our comparison pages; only their certified efficiencies change. Electric baseboards serve as the reference point.
How this amount is calculated
- Heat needed over the winter. A zone whose heat loss reaches 18,000 BTU/h ( kW) at −23.1 °C, the Montréal design temperature: kW × 24 h × 4,167 degree-days ÷ (18 − (−23.1)) = kWh of heat for 24-hour heating, all winter. Heating degree-days (base 18 °C) and design temperature: Natural Resources Canada, HOT2000 climate data, Montréal Intl station. With fewer hours per day (“Heating” slider), heat is reduced in the same proportion, for the heat pump as for the baseboards: this is a simplification that ignores the recovery after a temperature setback.
- Electricity for heating. Heat pump: heat × 3.412 ÷ HSPF2 region V, the AHRI certificate value published by NEEP. Region V is the coldest in the standard, and its calculation includes the electric backup planned for when the heat pump is no longer enough. Electric baseboards: 1 kWh of electricity for 1 kWh of heat.
- Electricity for cooling. 18,000 BTU/h ÷ SEER2 × hours per day × 60 days ÷ 1,000: the method of Hydro-Québec’s air conditioning calculator, with the seasonal SEER2 efficiency from the AHRI certificate. The number of hours is a scenario, adjustable above from 1 to 24 h. At 24 h, the calculation assumes rated capacity all day: that is a maximum, since a variable-speed unit slows down once the room is at the right temperature.
- Price. Hydro-Québec rate D in force on April 1, 2026: 7.065 ¢ per kWh up to 40 kWh per day, 11.142 ¢ beyond; the average price, 9.104 ¢, is the one Hydro-Québec’s calculators use. GST and QST included. Network access charges, the same with or without a heat pump, are not counted.
AirGreen method v1.1, November 9, 2026. An estimate is used to compare units under the same conditions. The actual bill depends on the house, the insulation, the settings and the use; this amount is not a promise.
18,000 on one box, 20,000 on the other: what the certificate really measures
The rated size is written in the model number: KUMXA181A, AJ020DXS3CG. The AHRI certificate, published by NEEP, measures something else: what each system delivers at a precise temperature. Choose a temperature and watch the certified capacity come out of each box.
Boxes: diagram. Capacities of the outdoor unit with its heads, AHRI certificates 214848473 (LG) and 216372795 (SAMSUNG), NEEP listings 392659 and 417116, 21.1 °C indoors in heating. The percentage is a simple division made by AirGreen; it appears in no certificate.
What each manufacturer publishes for the 9,000 + 9,000 combination
A multi-zone system’s certificate names no head: NEEP classifies both in the “Multizone All Non-Ducted” category. The manufacturers' tables, on the other hand, give values per combination. Here are those for two 9,000 BTU heads, next to the certified values.
Multi F LGRED LG
LG’s maximum capacity table for the combination 9,000 + 9,000 (performance data manual, table 2 for the KUMXA181A, p. 759) repeats the NEEP maximums exactly. For its rated values, LG puts another combination in bold, 7,000 + 12,000 (p. 570).
FJM Premium SAMSUNG
SAMSUNG’s Technical Data Book (v1.1, p. 29) gives, for 9,000 + 9,000 ductless 18,000 BTU/h rated in cooling and 21,800 BTU/h in heating at 8.3 °C. The certificate gives 21,000 and 22,000: in the same table, these values correspond to combinations of 21,000 BTU and more. Its “trend” capacity table gives 15,240 BTU/h at −25 °C for 9,000 + 9,000.
Solid bars: NEEP certified values. Hatched bars: manufacturer tables, outside the certificate, 21.1 °C indoors, 7.5 m of piping according to SAMSUNG. Same scale for the four bars on each card. In cooling, with two 9,000 BTU heads, both manufacturers therefore reach the same rated figure: 18,000 BTU/h.
Below −15 °C: every published number, at its exact temperature
Both certificates stop at the same temperature, −25 °C (−13 °F): this is one of the rare comparisons where the coldest point compares directly. At −15 °C, NEEP certifies 22,000 BTU/h for both; at −25 °C, 17,830 and 18,000 BTU/h. The manufacturers' tables fill in between the two.
On the chart, the certified points of both systems overlap at −15 °C (22,000 BTU/h each) and almost at −25 °C (17,830 and 18,000). For the SAMSUNG, two values at −15 °C and at −25 °C: the NEEP certified point and the 9,000 + 9,000 line of the SAMSUNG capacity table, which the manufacturer describes as “reference data on the capacity trend by temperature”. The certificate prevails. For the LG, the 9,000 + 9,000 maximum capacity table gives the same values as NEEP at −15 and −25 °C, and adds −20 °C.
What each manufacturer names
LG submittal for the KNUAB091A head and LG engineering manual for the KUMXA181A; SAMSUNG submittals for the AJ009DNADCG head (August 4, 2026) and the AJ020DXS3CG unit (July 10, 2026). Each line repeats what the manufacturer writes.
Multi F LGRED: heating down to −25 °C (−13 °F, wet bulb); factory-installed base pan heater; “Defrost / Deicing”.
FJM Premium: heating from −25 to 24 °C; base heater standard; extended start-up below −5 °C to protect the compressor.
Multi F LGRED: down to −10 °C outdoors; −20 °C with the ZLABGP04A wind baffle, sold separately.
FJM Premium: down to −10 °C outdoors (14 °F).
Multi F LGRED: Jet Cool / Jet Heat, sleep mode, 24-hour timer.
FJM Premium: WindFree (air below 0.15 m/s, vane closed), AI Auto, AI Energy, MAX, Good’sleep, Quiet, Dry.
Multi F LGRED: Built-in Wi-Fi, LG ThinQ app; AKB76044208 remote; group control.
FJM Premium: Built-in Wi-Fi, SmartThings app; remote rechargeable by solar cell or USB-C; consumption shown in the app.
Multi F LGRED: “Auto restart”; 3-minute restart delay.
FJM Premium: automatic restart after a power failure; soft start of the compressor.
Multi F LGRED: “3M Micro Dust” filter; automatic coil cleaning; R-32 leak sensor in the head.
FJM Premium: washable filter accessible from the top; “Auto Clean”; filter cleaning reminder; built-in A2L leak detection.
A feature missing from a column means the document consulted does not name it, not that it is absent. SAMSUNG also names a “Comfort Humidity Control” with a humidity sensor, without a quantified dehumidification rate.
The noise of each head, according to its manufacturer
LG publishes three speeds for the KNUAB091A head. SAMSUNG publishes the highest speed and the quiet mode for the AJ009DNADCG head. Both give a sound pressure in dB(A), for one head.
How to read these numbers. dB(A) measures a noise level as the ear perceives it: the lower the number, the quieter the unit. Each dot is a fan speed published by the manufacturer.
Why this is not a ranking. SAMSUNG measures at 1 m, in an anechoic chamber. LG states a tolerance of ±3 dB(A) for its heads and measures its outdoor units to ISO 3745. They do not publish the same speeds: we are comparing points that do not necessarily match the same setting.
One 9,000 BTU head, in the room
Speeds published by each manufacturer
Outdoor unit, outdoors
Heating, published value
Measurements taken by each manufacturer with its own method: read them separately, not as a ranking.
Sources: LG submittal KNUAB091A (36 / 32 / 27 dB(A), ±3) and LG KUMXA181A sheet (50 and 54 dB(A), ISO 3745); SAMSUNG FJM Standard Technical Data Book v1.2, p. 95 (head: 37 dB(A) at high speed, 23 in quiet mode, microphone at 1 m) and FJM Premium Technical Data Book v1.1, p. 76 (outdoor unit: 50 dB(A) in cooling, 51 in heating, 1 m in front and 1.5 m high).
On the wall, outdoors, in the piping
Wall heads to scale
5/8 in difference in width. The LG head is slightly taller (12 1/8 vs 11 3/4 in), the SAMSUNG slightly deeper (8 7/16 vs 7 9/16 in).
Outdoor units to scale
37 13/32 × 32 27/32 × 13 in · 147.7 lb
37 × 47 5/8 × 13 in · 191.8 lb
Widths at the same scale (W × H × D). The two-fan SAMSUNG unit is 14 3/4 in taller: worth knowing for a wall bracket or a stand above the snow. Photos: AirGreen images of the units sold.
Piping: the total length of the two lines
LG: no refrigerant to add up to 82 ft in total, then 0.22 oz per foot; 164 ft maximum, 9.8 to 82 ft per head. SAMSUNG: factory charged for 230 ft in total; the installation manual says not to add refrigerant, whatever the installation; 10 to 82 ft per head. Each line must also respect the per-head limit.
| Installation | Multi F LGRED | FJM Premium |
|---|---|---|
| Maximum piping length | 164 ft in total, 82 ft per head | 230 ft in total, 82 ft per head |
| Precharged length | 82 ft in totalLG engineering manual: length with no refrigerant to add; 0.22 oz/ft beyond. | 230 ft in totalSAMSUNG submittal: 109.3 oz charged for 230 ft; no addition according to the installation manual. |
| Maximum height difference | 49.2 ft24.6 ft between the two heads. | 49.2 ft24.6 ft between the heads. |
| Liquid – gas diameters | 1/4 – 3/8 in, one pair per head | 1/4 – 3/8 in, one pair per headThree pairs of connections on the outdoor unit. |
| Outdoor unit W × H × D, weight | 37 13/32 × 32 27/32 × 13 in, 147.7 lb | 37 × 47 5/8 × 13 in, 191.8 lb |
| Indoor unit, weightOne 9,000 BTU head | 19.73 lb | 19.6 lb |
| Electrical protectionAccording to the manufacturer | MOP 30 A (MCA 22.7 A) | 40 A breaker maximum (MCA 35.9 A) |
| DehumidificationOne 9,000 BTU head | 1.28 L/h2.70 pints/h according to LG. | Not published by the manufacturer.“Comfort Humidity Control” named, without a rate. |
| Advertised heating / cooling range | −25 to 18 °C / −10 to 48 °CHeating in wet bulb (−13 to 64 °F). | −25 to 24 °C / −10 to 46 °C−13 to 75 °F and 14 to 115 °F. |
Sources: LG engineering manual for the KUMXA181A, LG KUMXA181A submittal and LG KNUAB091A submittal; SAMSUNG AJ020DXS3CG submittal (July 10, 2026), SAMSUNG FJM R32 installation manual (DB68-13175A-00, p. 23 and 29) and SAMSUNG FJM Standard Technical Data Book v1.2 (p. 17). Clearances around the outdoor unit are in each installation manual; the installer confirms them on site.
What people ask us about these two systems
Why compare an 18,000 and a 20,000 BTU?
Because these are the two 2-zone options AirGreen offers in these lines: LG does not offer a 20,000 BTU Multi F LGRED, and SAMSUNG’s smallest FJM Premium unit is the 20,000. Both take two 9,000 BTU heads. In extreme cold, their certified capacities are very close: 22,000 BTU/h each at −15 °C, 17,830 and 18,000 BTU/h at −25 °C.
The SAMSUNG certificate says 21,000 BTU/h in cooling. Why does the label say 20,000?
The 20,000 is the rated size written in the model number AJ020DXS3CG. The AHRI certificate quantifies what the system delivered at 35 °C in the head combination rated by the manufacturer: 21,000 BTU/h. With two 9,000 BTU heads, SAMSUNG’s table gives 18,000 BTU/h. The LG is rated at 18,000 BTU/h, like its label.
Why does winter cost more with the SAMSUNG, when its SEER2 is higher?
Because winter is calculated with the HSPF2 region V and summer with the SEER2. The SAMSUNG has the higher SEER2 (23.0 vs 20.0) and the higher HSPF2 region IV (10.5 vs 9.8), but a lower HSPF2 region V (7.1 vs 8.1). Region V is the coldest in the standard, the one our estimate uses for Montréal.
What happens colder than −25 °C?
Both manufacturers publish a heating range that stops at −25 °C (−13 °F) and quantify nothing below it. The “Extreme cold” table shows, at −30 °C, each one’s last published value, at −25 °C, with what its manufacturer says.
Can a third head be added later?
On the SAMSUNG AJ020DXS3CG unit, yes: it has three pairs of connections and SAMSUNG publishes three-head combinations. The LG KUMXA181A unit connects two heads. A third head changes the capacity values; they are checked in the manufacturer’s tables at quote time.
Which LG head is supplied?
LG offers two 9,000 BTU heads for this system: KNUAB091A (Standard, white) and KNUAK091A (ARTCOOL Mirror, black). The dimensions, sound and dehumidification on this page are those of the KNUAB091A, from the LG submittal.
Are these systems eligible for rebates?
Eligibility depends on the official lists in force on the date of purchase, such as Hydro-Québec’s LogisVert list. We check the chosen system at quote time; no amount is promised on this page.
All AHRI and NEEP values
| Certified value | Multi F LGRED | FJM Premium |
|---|---|---|
| Cooling | ||
| Rated capacity at 35 °C | 18,000 BTU/h | 21,000 BTU/h |
| SEER2 | 20.0 | 23.0 |
| EER2 | 13.5 | 15.0 |
| Heating, same conditions | ||
| HSPF2 region IV / V | 9.8 / 8.1 | 10.5 / 7.1 |
| 8.3 °C: min. / rated / max.BTU/h | 10,248 / 22,000 / 24,000 | 7,600 / 22,000 / 32,000 |
| 8.3 °C: COP min. / rated / max. | 3.00 / 3.60 / 2.80 | 4.95 / 4.64 / 3.91 |
| −8.3 °C: min. / rated / max.BTU/h | 7,511 / 13,900 / 23,600 | 10,500 / 13,200 / 22,000 |
| −8.3 °C: COP min. / rated / max. | 2.50 / 2.59 / 2.56 | 2.96 / 2.95 / 2.22 |
| −15 °C: min. / rated / max.BTU/h | 6,262 / 19,800 / 22,000 | 10,500 / 22,000 / 22,000 |
| −15 °C: COP min. / rated / max. | 2.16 / 1.85 / 2.25 | 2.05 / 1.95 / 1.95 |
| Coldest point — same temperature, not highlighted | ||
| Test temperature | −25 °C (−13 °F) | −25 °C (−13 °F) |
| Capacity min. / max. | 4,636 / 17,830 BTU/h | 10,000 / 18,000 BTU/h |
| COP at maximum capacity | 2.31 | 1.61 |
| Certifications and refrigerant | ||
| ENERGY STAR / cold climate (NEEP) | Yes / Yes | Yes / Yes |
| ENERGY STAR directory, markets listed | United States, Canada | United States, Canada |
| AHRI certificate · NEEP listing | 214848473 · 392659Multi-zone, ductless heads | 216372795 · 417116Multi-zone, ductless heads |
| RefrigerantGWP according to the IPCC (AR4); ASHRAE 34 class | R-32 · GWP 675 · A2L | R-32 · GWP 675 · A2L |
highest marks the highest value of a given measurement, under the same conditions. It is not a recommendation. Capacities are not highlighted: the two systems do not have the same rated size. Nor is the HSPF2 line: the SAMSUNG is higher in region IV, the LG in region V.
Both are on the AirGreen website.
To choose for your two rooms, talk to our team: bring the size of each room, the planned outdoor location, the distance to each head and, if applicable, plans for a third room.
Where each number comes from
Data verified on November 9, 2026. Performance: AHRI certificates and NEEP database. Dimensions, sound, piping and features: according to the manufacturer. When a source contradicts the AHRI certificate, the certificate prevails.
Trademarks. LG, Multi F, LGRED, SAMSUNG, Free Joint Multi, WindFree and SmartThings are trademarks of their respective owners. Logos are used only to identify the products compared. AirGreen is a retailer of both brands; this page is not produced, sponsored or approved by the manufacturers.
Photos: AirGreen and manufacturers, for identification.
Does a data point look wrong? Write to us : every reported data point is checked again.