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FUJITSU AIRSTAGE ALTAIR 300 and ALTAIR 500: what changes from one series to the next
Two 12,000 BTU FUJITSU AIRSTAGE wall units on R‑32, at 208/230 V, sold by AirGreen. At −15 °C, the ALTAIR 300 is certified for slightly more maximum heat; over a season, the ALTAIR 500 has the higher certified efficiencies. Both figures are true: they do not measure the same thing.
What the electricity costs, in dollars, winter and summer
AirGreen estimate for the same 12,000 BTU/h zone in Montréal, at Hydro-Québec Rate D, taxes included. Both heat pumps are calculated exactly the same way, with the same method as on all our comparison pages; only their certified efficiencies change. Electric baseboards serve as a reference point.
How this amount is calculated
- Heat needed over the winter. A zone whose heat loss reaches 12,000 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 (base 18 °C) 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 and for the baseboards alike: 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 expected when the heat pump is no longer enough. Electric baseboards: 1 kWh of electricity for 1 kWh of heat.
- Electricity for cooling. 12,000 BTU/h ÷ SEER2 × hours a day × 60 days ÷ 1,000: the method of Hydro-Québec’s air-conditioning calculator, with the SEER2 seasonal 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 effect on April 1, 2026: 7.065¢ per kWh up to 40 kWh a day, 11.142¢ beyond that; 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 meant to compare units under the same conditions. The actual bill depends on the house, insulation, settings and use; this amount is not a promise.
Peak output and seasonal efficiency do not tell the same story
Each unit is a point on two axes. Vertically, the certified maximum heat at one test temperature. Horizontally, the efficiency over a full season. Change the temperature or the seasonal measure: both points move.
Height: the peak
The maximum heat the unit delivers at full speed, measured at a single temperature, in a laboratory test. It is a snapshot: it tells you what the unit can give at the most demanding moment.
Width: the season
The HSPF2 divides the heat of an entire season by the electricity consumed, taking into account every winter temperature and the electric backup. The SEER2 does the same for summer. It is a film: it is what weighs on the bill.
AHRI certified values published by NEEP (records 372687 and 392096), accessed November 9, 2026. Region IV: the standard’s reference climate; Region V: colder. No score is calculated: each axis is a published value.
Maximum heat changes sides with the temperature
At 8.3 °C and at −8.3 °C, the ALTAIR 500 is certified for more maximum heat. At −15 °C, it is the ALTAIR 300, by 300 BTU/h. At the −15 °C rated point, the order reverses again: 8,200 and 8,500 BTU/h. Bar: maximum capacity; yellow tick: rated capacity.
Below −15 °C: the last published figure, then the stated range
NEEP certifies both units at −15 °C, under the same conditions: 8,800 and 8,500 BTU/h maximum, with COPs of 2.08 and 2.29. The manufacturer’s published heating range stops there, for both units. Lower down, no document gives a capacity; at each temperature, the table shows the last published figure and what the manufacturer writes.
What each document names
FUJITSU AIRSTAGE technical manual DR_AS255ES_01 (ALTAIR 300, 208/230 V) and brochure FG8151D (ALTAIR 500). Each card repeats what the manufacturer writes.
ALTAIR 300: Auto, Cool, Dry, Fan, Heat; Powerful and Economy buttons on the remote.
ALTAIR 500: Economy, Energy Saving, Powerful, Minimum Heat; automatic defrost.
ALTAIR 300: 4 speeds (High, Medium, Low, Quiet).
ALTAIR 500: 6 speeds and Auto.
ALTAIR 300: wireless remote; Wi-Fi with the optional UTY-TFSXH4 WLAN adapter.
ALTAIR 500: backlit wireless remote; Wi-Fi and the AIRSTAGE Mobile app with a compatible USB WLAN adapter.
ALTAIR 300: automatic restart.
ALTAIR 500: automatic restart.
ALTAIR 300: filter maintenance reminder, adjustable interval.
ALTAIR 500: washable filter; ProCore copper indoor coil.
ALTAIR 300: adjustable fixed modes (heat pump, heating only, cooling only).
ALTAIR 500: BACnet and Modbus, external inputs and outputs.
How loud each one is, according to FUJITSU AIRSTAGE
Four published speeds for the ALTAIR 300, six for the ALTAIR 500, with a sound pressure in dB(A) for each. Outside, both units are rated at 48 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. The dots run from Quiet, the slowest speed, to High.
Why this is not a ranking. Speeds do not correspond to the same airflow from one series to the other, and the documents come from two kinds of publication (technical manual, brochure). They do not state the measuring distance.
Indoor unit, in the room
Cooling, all published speeds
Outdoor unit, outside
Cooling and heating
Measurements published by FUJITSU AIRSTAGE for each series, with no distance stated: read them as reference points, not as a ranking.
On the wall, outside, in the piping
Indoor units to scale
The ALTAIR 300 is 2 1/2 in narrower and 13/16 in shorter, at 17 lb instead of 21 lb. Outside, both units list the same width, 26 1/8 in.
| Installation | ALTAIR 300 | ALTAIR 500 |
|---|---|---|
| Maximum piping length | 65 ft20 m, minimum 10 ft (manual DR_AS255ES_01, p. 46). | 66 ft20 m, minimum 10 ft (brochure FG8151D). Same length in metres. |
| Precharged length | 49 ft | 49 ft |
| Maximum height difference | 49 ft | 49 ft |
| Liquid – gas diameters | 1/4 – 3/8 in | 1/4 – 3/8 in |
| Outdoor unit W × H × D, weight | 26 1/8 × 21 5/16 × 11 7/16 in, 55 lb | 26 1/8 × 21 5/16 × 11 7/16 in, 57 lb |
| Indoor unit, weight | 17 lb | 21 lb |
| Power supplyPer the manufacturer | 208/230 V, 60 Hz | 208/230 V, 60 Hz; 15 A breaker |
| Dehumidification | 1.57 L/h | 1.59 L/h |
| Stated heating / cooling range | −15 to 24 °C / 10 to 50 °C | −15 to 24 °C / −10 to 50 °C |
ALTAIR 300: technical manual DR_AS255ES_01 (September 5, 2025), models ASUH12KNAS and AOUH12KNAS1 at 208/230 V. There is also a 115 V ALTAIR 300, with other model numbers; it is not compared here. ALTAIR 500: brochure FG8151D (rev. 4/2025).
What people ask about these two ALTAIR units
Why does the ALTAIR 300 have more maximum heat at −15 °C, with a lower HSPF2?
They are two different measurements. NEEP certifies 8,800 BTU/h maximum at −15 °C for the ALTAIR 300 and 8,500 for the ALTAIR 500: that is a single point, at full speed. HSPF2 (9.0 and 10.5 in Region IV) sums up a whole season, at every temperature and every speed. At −15 °C, the ALTAIR 500 also delivers its heat with a higher COP, 2.29 versus 2.08.
What exactly does HSPF2 measure?
The heat delivered over a heating season, in BTU, divided by the electricity consumed, in watt-hours, under the AHRI 210/240 standard. Region IV is the standard’s reference climate, Region V a colder climate. It is the value used for the cost calculation higher up on this page.
Which one is ENERGY STAR certified?
The ALTAIR 500 (AHRI certificate 215212610) is in the ENERGY STAR directory, certified April 17, 2026, without the cold climate designation. AHRI certificate 217505656 for the 208/230 V ALTAIR 300 is not listed there (accessed November 9, 2026), and NEEP shows it as not certified.
Is the ALTAIR 300 more compact?
Indoors, yes: 9 13/16 × 30 5/16 × 8 9/16 in and 17 lb, versus 10 5/8 × 32 13/16 × 8 3/4 in and 21 lb for the ALTAIR 500. Outside, both units have the same published dimensions, 26 1/8 × 21 5/16 × 11 7/16 in, at 55 and 57 lb.
What happens below −15 °C?
No document puts a figure on it. For the ALTAIR 300 as for the ALTAIR 500, −15 °C is both the coldest point certified by NEEP and the bottom of the published heating range. If the heat pump has to carry most of the heating below that, compare it with series certified at −25 or −30 °C.
Are they eligible for rebates?
Eligibility depends on the official list in force on the date of purchase. This page promises no amount; the current list is checked when you get your quote.
All AHRI and NEEP values
| Certified value | ALTAIR 300 | ALTAIR 500 |
|---|---|---|
| Cooling | ||
| Rated capacity at 35 °C | 12,000 BTU/h | 12,000 BTU/h |
| SEER2 | 18.0 | 24.0 |
| EER2 | 10.35 | 11.7 |
| Heating, same conditions | ||
| HSPF2 Region IV / V | 9.0 / 7.24 | 10.5 / 7.9 |
| 8.3 °C: min. / rated / max.BTU/h | 3,100 / 12,000 / 13,900 | 2,700 / 14,000 / 17,000 |
| 8.3 °C: COP at min., rated, max. | 4.33 / 3.35 / 2.45 | 6.09 / 3.80 / 3.69 |
| −8.3 °C: min. / rated / max.BTU/h | 2,700 / 7,500 / 10,100 | 2,900 / 8,700 / 11,000 |
| −8.3 °C: COP at min., rated, max. | 2.64 / 2.62 / 2.39 | 4.05 / 2.86 / 2.69 |
| −15 °C: min. / rated / max.BTU/h | 1,400 / 8,200 / 8,800 | 2,100 / 8,500 / 8,500 |
| −15 °C: COP at min., rated, max. | 1.64 / 2.18 / 2.08 | 2.56 / 2.29 / 2.29 |
| Coldest certified point — the same for both | ||
| Test temperature | −15 °C (5 °F) | −15 °C (5 °F) |
| Capacity min. / max. | 1,400 / 8,800 BTU/h | 2,100 / 8,500 BTU/h |
| COP at maximum output | 2.08 | 2.29 |
| Certifications and refrigerant | ||
| ENERGY STAR / cold climate | No / NoNot in the ENERGY STAR directory | Yes / No |
| AHRI certificate · NEEP record | 217505656 · 372687 | 215212610 · 392096 |
| RefrigerantGWP per the IPCC (AR4); ASHRAE 34 class | R-32 · GWP 675 · A2L | R-32 · GWP 675 · A2L |
higher marks the higher value of the same measurement, under the same conditions. It is not a recommendation. Capacities and COPs by test point are not highlighted: the order changes with the point you read.
Both are on the AirGreen website.
To choose for your room, talk it over with our team: bring the room dimensions, the planned outdoor location and your current heating.
Where each figure comes from
Data checked 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, ALTAIR and AIRSTAGE are trademarks of their respective owners. Logos are used only to identify the products compared. AirGreen is a retailer of this brand; this page is not produced, sponsored or endorsed by the manufacturer.
Photos: AirGreen and manufacturers, for identification.
Does a figure look wrong? Write to us: every reported figure is rechecked.