12.3 kWCarrier QSM Slim Line 12.3kW Ducted System
The 12.3kW Carrier QSM Slim Line Ducted (indoor 42QSM125D8S) is rated at 12.3kW cooling and sized for typical three-bedroom single-storey homes. As a guide it covers roughly 82 to 98m² of conditioned floor area, depending on zoning, insulation and ceiling height. It runs R32 refrigerant and carries Carrier’s 7 year residential parts and labour warranty. For more bedrooms or a larger floor plan, the 13.6kW is the next step up.
Part of the Carrier QSM Slim Line Ducted range, Carrier's ducted system line, in 8 sizes. Running costs below use the Sydney median rate; the Eastern Suburbs and Western Sydney pages cost systems on their own network tariffs. Check the size against your rooms, compare it with other 12.3 kW options, or ask about supply and installation.
About $860 a year at the current Sydney median electricity rate: $321 of cooling plus $539 of heating, from the official GEMS test figures.
The Carrier QSM Slim Line 12.3kW uses 970 kWh annually for cooling and 1626 kWh annually for heating, based on official GEMS energy label testing for Sydney's climate zone. The system carries a 3.5-star cooling rating and 2.5-star heating rating under the same zoned label standard. Running cost depends on your local electricity rate and how often you operate the system.
Efficiency is measured by AEER for cooling at 3.36 and ACOP for heating at 3.98. The unit uses R32 refrigerant. Your installer can discuss how these figures translate to your household's likely usage patterns and budget.
Source: Australian GEMS registry · median of 170 Sydney residential tariffs, including GST · Refreshed monthly · Last updated October 2026
Specifications
From the manufacturer’s published range data. We confirm the exact configuration when we quote.
About the Carrier QSM Slim Line Ducted range| Brand | Carrier |
|---|---|
| Model | 42QSM125D8S |
| Series | Carrier QSM Slim Line Ducted |
| System type | Ducted System |
| Capacity | 12.3 kW |
| Refrigerant | R32 |
| ESP (rated/max) | up to 50 / 160 Pa |
| Power supply | 220-240V single phase |
| Warranty | 7 year parts & labour (residential) |
Other 12.3kW options
All ducted systems
Carrier QSH High Static 12.4kW
Model 42QSH125D8S-1. 200Pa static pressure, Long duct runs
Samsung S2 Ducted 12.5kW
Model AC120TNHPKG / AC120TXAPKG. Whole home, SmartThings
Fujitsu Mid Static Slimline Ducted 12.5kW
Model ARTH45KMTAP. Whole home, Single & three phase