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

Daikin · Single-Zone

Daikin Atmosphera 18,000 BTU

FTXM18WVJU9 / RXM18WVJU9

~$4,527approximate retailer price at last check, equipment only

BTU/h: 18k
Volts: 208/230
Zones: 1
SEER2: 22.7
HSPF2: 10
Heats to: -13°F
Refrig.: R-32
Covers: 800 ft²
Wi-Fi: Built in

Best forDaikin loyalists who want a quiet 18k and value the installer network over the lowest price.

Overview

The 18,000 BTU Atmosphera is rated 22.7 SEER2 and 10.0 HSPF2 and heats down to -13°F. Its list price runs from roughly $4,330 to $4,530, which is hard to justify against a Mitsubishi GX18 ($3,880) with the same low-temperature capability but a higher published HSPF2, or the Fujitsu XLTH 18k at 27.5 SEER2. What it offers is Daikin's quiet indoor unit, the 12-year registered parts coverage and a head that is built for later multi-zone expansion. Wi-Fi is built in for the Daikin Comfort Control app.

12-year parts, registered
Head reusable in a later multi-zone

Cold-weather output

At 5°F it still makes its full 47°F rated heat, according to the certified NEEP listing for this pairing. Daikin rates it to keep running down to -13°F.

COP at 5°F: 1.8
Refrigerant: R-32
AHRI cert.: 212494259
ENERGY STAR cold climate: No

Pairing: RXM18WVJU with FTXM18WVJU. Checked October 8, 2026 on NEEP's ccASHP list; a different head or condenser posts different numbers.

Strengths and catches

Strengths

+Indoor sound range 23 to 45 dB(A) per the retailer
+12-year parts warranty with registration
+Head can be reused when planning multi-zone expansion

Catches

−$4,300 to $4,500 for equipment alone, above the Mitsubishi GX18 and Fujitsu 18k
−10.0 HSPF2 is ordinary for the price
−Parts-only coverage

Questions buyers ask

What space is the Daikin Atmosphera 18k meant for?+

Daikin lists about 800 sq ft. NEEP certifies 21,600 BTU of heating at 47°F. It suits a large open area, not several closed rooms.

Can it be the primary heat in a cold winter?+

It is rated to -13°F, and NEEP certifies 21,600 BTU at 5°F, the same as at 47°F, with a COP of 1.8. It holds output in the cold. For a harsh climate, check against your design load.

How does the price compare with the Mitsubishi GX18 and Fujitsu Orion 18k?+

At about $4,527 it costs more than the GX18 (about $3,880) and the Fujitsu XLTH 18k (about $4,036). Its 22.7 SEER2 and 10.0 HSPF2 are not better than either. The premium is for the brand and the parts warranty.

What electrical and install details apply?+

Breaker size is 18.8A minimum and 20A maximum, the lineset is 1/4" x 1/2" precharged to 49 ft, and the refrigerant is R-32 (A2L). Use a trained installer.