Home / Comparisons / 3-ton central heat pumps
FUJITSU AIRSTAGE CENTAURI XLTH R32 and LG LGRED R32, figure by figure
Two 3-ton R-32 central heat pumps, ENERGY STAR cold climate per NEEP and offered by AirGreen. On paper their piping limits look alike: 246 ft maximum on each side. What changes is the length already charged at the factory. This page shows what that means depending on where the outdoor unit sits.
CENTAURI XLTH R32 · 36,000 BTU
AMUH36KUAS / AOUH36KUAH1 · AHRI 217895717
See the product page
What the electricity costs, in dollars, winter and summer
AirGreen estimate for the same 36,000 BTU/h (3-ton) house in Montréal, on Hydro-Québec Rate D, taxes included. On heating the certificates are close: HSPF2 Region V of 8.2 for the CENTAURI XLTH and 7.85 for the LGRED, or a little under 5% more electricity for the LGRED for the same heat. In cooling, the SEER2 values (18.3 and 18.2) are on par. The certificates give 36,000 and 33,000 BTU/h of cooling at 35 °C: the calculation uses the common nominal size, 36,000 BTU/h, for both, with electric baseboards as the reference.
How this amount is calculated
- Heat to supply over the winter. A house whose heat loss reaches 36,000 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 round-the-clock heating, all winter. Heating degree-days (18 °C base) and design temperature: Natural Resources Canada, HOT2000 climate data, Montréal Intl station. With fewer hours a day (“Heating” slider), the heat is reduced in the same proportion, for the heat pump as for the baseboards: this simplification ignores the recovery after a temperature setback.
- Heating electricity. 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 heat expected when the heat pump is no longer enough. Electric baseboards: 1 kWh of electricity for 1 kWh of heat.
- Cooling electricity. 36,000 BTU/h ÷ SEER2 × hours a 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 long: that is a ceiling, since a variable-speed unit slows down once the room reaches its set temperature.
- Price. Hydro-Québec Rate D in effect April 1, 2026: 7.065¢ per kWh up to 40 kWh a day, 11.142¢ beyond; the average price, 9.104¢, is the one Hydro-Québec’s calculators use. GST and QST included. Grid access charges, the same with or without a heat pump, are not counted.
AirGreen method v1.1, November 9, 2026. An estimate is a way to compare units under the same conditions. The actual bill depends on the house, its insulation, the settings and how it is used; this amount is not a promise.
Move the outdoor unit: the refrigerant line follows
The air handler is in the basement. Drag the outdoor unit across the yard, or onto a higher stand, or use the sliders. The page works out the line length along a simple route and compares it with each manufacturer’s published limits: minimum length, factory-precharged length, maximum length and height difference.
Assumed route: 5 ft from the air handler to the wall in the basement, 8 ft up to the exit above ground, then the chosen distance and height. The height difference runs from the air handler (8 ft below the exit) to the outdoor unit. Refrigerant amounts are orders of magnitude calculated with the published rate; the installer always follows the installation manual and the nameplate.
What LGRED means, and what the certificates say
Per LG, RED stands for “Reliable to Extreme Degrees”: it is the name LG gives its extreme-cold heating technology (LG press release, November 2017). For this system, LG submittal sheet KSSLA361A states heating down to −25 °C (−13 °F) and publishes a maximum capacity of 33,000 BTU/h at −15 °C, for 40,000 BTU/h rated at 8.3 °C. The certified figures are lower.
Certified seasonal efficiencies
Same scale for both units on each row.
Certified maximum capacity
At the three temperatures where NEEP measures both units. Vertical line: 36,000 BTU/h.
Below −15 °C: what LG publishes, what NEEP certifies
NEEP measures both systems at the same temperatures down to −15 °C. Lower down, each has its coldest point: −26.1 °C for the CENTAURI XLTH, −25 °C for the LGRED. LG also publishes maximum capacities in its submittal sheet, including one at −20 °C. Each value is placed at its own temperature, with its source; nothing is calculated between two points.
What each manufacturer writes, line by line
FUJITSU AIRSTAGE submittal sheet 36KUAH1M and Centauri brochure FG8161D; LG submittal sheet KSSLA361A (March 2026). The cards stick to the two manufacturers' own wording.
CENTAURI XLTH: heating stated down to −26 °C, no low-temperature cutoff; built-in heated base pan.
LGRED: heating stated down to −25 °C; heated base pan standard; GoldFin-treated coil.
CENTAURI XLTH: down to −21 °C (−5 °F) outside.
LGRED: down to −15 °C (5 °F) outside, and up to 48 °C (118 °F) in hot weather.
CENTAURI XLTH: Auto and four speeds; up to 0.8 in. w.c.; multi-position.
LGRED: three speeds; constant-airflow ECM motor, whatever the allowed static pressure; 0.1 to 1.0 in. w.c.; multi-position, downflow with PNDFA0 kit.
CENTAURI XLTH: third-party 24 V thermostat through the UTY-TTRXZ1 interface; wired controls, IR kit and Wi-Fi optional.
LGRED: optional LG controls (Simple, Standard III, MultiSITE, button sensor); the wireless remote requires an LG wall control, as the air handler has no infrared receiver; Wi-Fi through the optional PWFMDD200 module.
CENTAURI XLTH: optional electric heater kits (UTZ-EU series), on a dedicated circuit.
LGRED: ANEHxx3Cx electric heater kits and PRARH1 auxiliary heat kit, optional.
CENTAURI XLTH: leak sensor built into the air handler.
LGRED: R-32 leak sensor among the control functions.
CENTAURI XLTH: Economy mode, weekly timer, sleep mode, auto restart.
LGRED: hot start, self-diagnosis, soft dry, auto changeover, child lock, sleep mode, weekly timer, auto restart.
CENTAURI XLTH: inverter compressor; one outdoor fan.
LGRED: inverter compressor; two outdoor fans; electronic expansion valve.
CENTAURI XLTH: 20 × 20 in. filter base available as an option (86ET0001).
LGRED: access panel for a 20 × 20 × 1 in. filter, field supplied.
How loud each one is, per its manufacturer
Both manufacturers publish one level per speed for the air handler and one level for the outdoor unit, as sound pressure measured in an anechoic chamber. LG specifies the standard, ISO 3745, and a tolerance of ±1 dB(A).
How to read these figures. dB(A) measures a noise level as the ear perceives it: the lower the figure, the quieter the unit. Here FUJITSU AIRSTAGE publishes four speeds and LG three: compare them speed by speed, not only at maximum.
Why this is not a ranking. Both measurements are made in an anechoic chamber, but each manufacturer has its own method and its own speeds; neither publishes the distance. A few dB(A) of difference can come from the method as much as from the unit.
Air handler
Published values, by speed
Outdoor unit, outside
Published sound pressure
Two measurements in an anechoic chamber, but two methods and different speeds: read them separately, not as a ranking.
In the basement, outside and in the piping
All four units at the same scale
Net heights and weights per the submittal sheets (LG air handler: 55 3/16 in cabinet, 55 7/8 in with the top flange). Photos: FUJITSU AIRSTAGE submittal sheet 36KUAH1M and LG submittal sheet KSSLA361A.
| Installation | CENTAURI XLTH | LGRED |
|---|---|---|
| Maximum piping length | 246 ft | 246 ftEquivalent length, per LG. |
| Minimum piping length | 17 ft | 16.4 ft |
| Precharged length | 98 ft | 24.6 ft |
| Refrigerant added beyond the precharged length | 0.43 oz/ft | 0.43 oz/ft |
| Maximum height difference | 98 ft | 98.4 ft |
| Liquid – gas diameters | 3/8 – 5/8 in | 3/8 – 5/8 in |
| Factory refrigerant charge | 5 lb 15 oz | 106 oz |
| Outdoor unit W × H, weight | 37 × 39 5/16 in, 159 lb | 37 13/32 × 54 1/4 in, 190.2 lb |
| Indoor unit W × D × H, weight | 21 × 21 × 48 in, 137 lb | 21 × 21 3/8 × 55 3/16 in, 141 lb |
| Indoor airflow | 1,200 CFM (high speed) | 1,050 CFM (high speed) |
| Maximum external static pressure | 0.8 in. w.c. | 1.0 in. w.c. |
| Electrical protectionPer the manufacturer | Breaker max. 35 A (MCA 33.9 A) | MOP 35 A (MCA 32 A) |
| Dehumidification | 3.82 L/h | 6.9 pints/h |
| Stated heating / cooling range | −26 to 24 °C / −21 to 50 °C | −25 to 18 °C (b.h.) / −15 to 48 °C |
Sources: FUJITSU AIRSTAGE submittal sheet 36KUAH1M (version 20260123A); LG submittal sheet KSSLA361A (SB_SZ_Multi_Position_AHU_LGRED_R32, March 10, 2026), dimensioned drawings on pages 3 and 4. LG states the heating range in wet bulb.
What people ask about these two central systems
What does LGRED mean?
Per LG, RED stands for “Reliable to Extreme Degrees”: it is the name of LG’s extreme-cold heating technology. For this system, the LG sheet states heating down to −25 °C; certified capacities by temperature are in the Extreme cold section.
Why does the page use 36,000 BTU/h if the LGRED is certified at 33,000?
Both are sold as 3-ton systems. The LGRED certificate gives 33,000 BTU/h of cooling at 35 °C, the CENTAURI XLTH certificate 36,000. The estimated cost uses the common nominal size, 36,000 BTU/h, for both; certified capacities are shown as they are elsewhere.
What does the precharged length change for me?
Up to that length, the outdoor unit holds enough refrigerant for the line: 98 ft for the CENTAURI XLTH, 24.6 ft for the LGRED. Beyond that, the installer adds some at the published rate, 0.43 oz per foot for both. Both accept the same maximum length, 246 ft.
Is a thermostat or control supplied?
Neither submittal sheet lists a thermostat among the supplied parts. FUJITSU AIRSTAGE and LG controls appear there as options. LG notes that its wireless remote requires an LG wall control. The written quote states what is included.
Which one heats more in extreme cold?
At the temperatures NEEP measures for both, the CENTAURI XLTH has the higher certified maximum capacity: 41,000 BTU/h against 33,000 at −15 °C. Lower down, the points are not at the same temperature: 32,000 BTU/h at −26.1 °C for the CENTAURI XLTH, 28,000 at −25 °C for the LGRED.
Are they eligible for rebates?
Both are listed as ENERGY STAR cold climate in the NEEP database. Eligibility depends on the official list in effect on the purchase date; this page promises no amount.
All AHRI and NEEP values
| Certified value | CENTAURI XLTH | LGRED |
|---|---|---|
| Cooling | ||
| Rated capacity at 35 °C | 36,000 BTU/h | 33,000 BTU/h |
| SEER2 | 18.3 | 18.2 |
| EER2 | 11.4 | 13.0 |
| Heating, same conditions | ||
| HSPF2 Region IV / V | 10.2 / 8.2 | 9.6 / 7.85 |
| 8.3 °C: min. / rated / max.BTU/h | 9,200 / 38,000 / 43,000 | 11,904 / 40,000 / 43,000 |
| 8.3 °C: COP min. / rated / max. | 3.80 / 3.89 / 3.28 | 4.53 / 3.78 / 3.07 |
| −8.3 °C: min. / rated / max.BTU/h | 8,300 / 25,200 / 41,600 | 15,240 / 25,400 / 39,000 |
| −8.3 °C: COP min. / rated / max. | 3.86 / 2.90 / 2.25 | 2.83 / 2.80 / 2.38 |
| −15 °C: min. / rated / max.BTU/h | 7,900 / 41,000 / 41,000 | 8,628 / 33,000 / 33,000 |
| −15 °C: COP min. / rated / max. | 3.86 / 1.98 / 1.98 | 2.61 / 2.00 / 2.00 |
| Coldest point — different temperatures, not highlighted | ||
| Test temperature | −26.1 °C (−15 °F) | −25 °C (−13 °F) |
| Capacity min. / max. | 6,000 / 32,000 BTU/h | 3,600 / 28,000 BTU/h |
| COP at maximum capacity | 1.82 | 1.64 |
| Listings and refrigerant | ||
| ENERGY STAR / cold climate (NEEP) | Yes / Yes | Yes / Yes |
| AHRI certificate · NEEP record | 217895717 · 306746 | 215588576 · 422333 |
| RefrigerantGWP per the IPCC (AR4); ASHRAE 34 class | R-32 · GWP 675 · A2L | R-32 · GWP 675 · A2L |
higher marks the higher value of a given measure, under the same conditions. It is not a recommendation. Capacities and COPs by point are not highlighted: the order changes depending on the point read. The LG submittal sheet prints 29,000 BTU/h at −25 °C; NEEP certifies 28,000 BTU/h: the page follows AHRI certificate 215588576.
Both are on the AirGreen website.
To choose for your house, talk it over with our team: bring the heated area, the condition of your ducts, the planned outdoor spot and your current heating.
Where each figure comes from
Data checked on November 9, 2026. Performance: AHRI certificates and the NEEP database. Dimensions, sound, piping and features: per the manufacturer. When a source contradicts the AHRI certificate, the certificate prevails.
Trademarks. FUJITSU AIRSTAGE, CENTAURI, LG and LGRED are trademarks of their respective owners. Logos are used only to identify the products compared. AirGreen is a dealer for both brands; this page is not produced, sponsored or endorsed by the manufacturers. The FUJITSU AIRSTAGE system is also sold under the name GENERAL AIRSTAGE.
Photos: AirGreen and the manufacturers, for identification.
Does a figure look wrong to you? Write to us : every reported figure is checked again.