The maker's photo for this series, not this exact size; the outdoor unit grows with capacity

Fujitsu General · Single-Zone

Fujitsu Airstage Orion XLTH 18,000 BTU

ASUH18KZAS / AOUH18KZAH1

~$4,036approximate retailer price at last check, equipment only

BTU/h: 18k
Volts: 208/230
Zones: 1
SEER2: 25.5
HSPF2: 12.5
Heats to: -15°F
Refrig.: R-32
Covers: 720 ft²
Wi-Fi: Add-on

Best forPrimary living spaces in cold climates that need 18k of capacity without the efficiency penalty.

Overview

At 18,000 BTU the Orion XLTH is certified at 25.5 SEER2 and 12.5 HSPF2, a small step down from the 15k's 27.5 and 12.7. Fujitsu publishes 19,000 BTU of cooling and up to 25,000 BTU of heat, with heating at rated output to -15°F. It suits a primary living space of around 700 sq ft in a cold place. The retailer price of about $4,040 is $760 over the 15k and lands above the Mitsubishi GX18 ($3,880), though the Fujitsu is the more efficient system by a wide margin. The Daikin Aurora 18k is the nearest alternative from another maker. Wi-Fi again needs an accessory.

Same lineset as the 15k
25,400 BTU at 5°F (NEEP)

Cold-weather output

At 5°F it makes more heat than its 47°F rating (118%), according to the certified NEEP listing for this pairing. Fujitsu General rates it to keep running down to -15°F.

COP at 5°F: 2.02
Refrigerant: R-32
AHRI cert.: 215647921
ENERGY STAR cold climate: Yes

Pairing: AOUH18KZAH1 with ASUH18KZAS. Checked October 8, 2026 on NEEP's ccASHP list; a different head or condenser posts different numbers.

Strengths and catches

Strengths

+25.5 SEER2 / 12.5 HSPF2, well ahead of the Mitsubishi GX18
+Up to 25,000 BTU of heat is published
+Uses the same 1/4" x 1/2" lineset as the 15k

Catches

−About $4,040 for equipment alone, above the Mitsubishi GX18
−Wi-Fi is an accessory purchase
−Registration within 60 days required for the 10-year term
−Thinner installer network than Mitsubishi in many metros

Questions buyers ask

What square footage can the Fujitsu XLTH 18k cover?+

It is listed for about 720 sq ft, a large living room or open main floor. NEEP certifies 21,600 BTU of heating at 47°F. A single head cannot condition closed-off rooms elsewhere in the house.

Will it carry a house through a cold winter?+

Fujitsu's rating goes to -15°F, and NEEP certifies 25,400 BTU at 5°F with a COP of 2.02. That is about 1.4 times the nameplate, so it keeps up in the cold. Whole-house use depends on layout and insulation.

Is it better than the Mitsubishi GX18?+

On paper, yes for efficiency: 25.5 SEER2 and 12.5 HSPF2 against 22.5 and 10, and 25,400 BTU at 5°F against 19,000. It costs about $4,036 against about $3,880. The Mitsubishi goes to -22°F rather than -15°F and has Wi-Fi built in.

What warranty coverage can I get?+

Five years parts and 7 years compressor as standard, 10 years each with registration within 60 days, and 12 years through a Fujitsu Elite contractor install. Plan on a professional install to reach the top tier.