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.
The Carrier QSM Slim Line 12.3kW uses about 970 kWh of electricity a year for cooling and 1626 kWh for heating, based on official GEMS government test figures for Sydney's climate zone. At an electricity rate of 34.7 cents per kWh, the median of 170 Sydney residential plans as calculated in June 2026, that works out to an estimated $337 a year for cooling and $564 for heating, or about $901 across the year.
On efficiency, this system holds a zoned cooling rating of 3.5 stars and a zoned heating rating of 2.5 stars for Sydney, with a rated AEER of 3.3561 and a rated ACOP of 3.9817. It uses R32 refrigerant.
Source: Australian GEMS registry · median of 170 Sydney residential tariffs · Refreshed monthly · Last updated June 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