Comfort™ Crossover Air Handler Unit
45MUAA
Designed for seamless versatility, compact performance, and exceptional home comfort.
Adaptable, efficient, and compact, the Comfort Crossover Air Handler Unit offers versatility for your home. A great option for homes transitioning from gas furnaces or looking to pair with crossover heat pumps, its four-position installation capability promotes flexibility. Enhanced with a variable-speed ECM motor, this unit synchronizes with Carrier crossover heat pumps such as the 37MURA and the 37MUHA, helping to ensure energy efficiency and refined performance.
Features
Install with select outdoor units to experience consistent indoor climates with variable-speed technology that helps minimize temperature swings and enhances comfort.
Capable of supporting single-zone systems.
Operating with sound levels as low as 25.5 decibels, this provides a quiet environment inside your home.
Compatible with Puron Advance™ refrigerant, which reduces global warming potential by 75% compared to traditional options, while maintaining non-ozone-depleting properties.
Experience peace of mind with Carrier's Consumer Choice Warranty. Upon timely registration, on eligible equipment select either a 10-year parts only limited warranty or a 5-year parts, plus a 3-year labor limited warranty.1
At a glance
Type
Compatible with single-zone outdoor unitsOverall Efficiency
Select sizes ENERGY STAR® certifiedSound Level
As low as 25.5 decibelsApplication
ResidentialCompatibility
Compatible with all 24V ThermostatsRefrigerant
Puron Advance ™Build an efficient, cost-effective and comfortable living environment with a crossover air handler.
Customer Reviews
3.6 /5
3.6 rating of Reviews (8)
Works O.K.
January 12, 2026
Nine months after installation, the air handler blew a fuse last week, requiring a service call. It's not clear whether the problem was hardware-related or due to the equipment's installation. Other than that issue, it has been working O.K.
#1
January 2, 2026
My electric bill is much lower
Documents
Brochure
Carrier Crossover Consumer Brochure (Spanish)
Carrier Crossover Brochure featuring Puron Advance
Carrier Crossover Consumer Brochure (French)
Crossover Maintenance Flyer
Owner's Manual
45MUAAQ Régulateur d’air croisé Capacités 18 000 à 60 000 K - Manuel d’utilisation
45MUAA Crossover Air Handler Sizes 18K - 60K - Owner's Manual
Warranty Card
CAC/BDP Limited Warranty Certificate Limited Warranty for Ductless Split Units
California residents please see Proposition 65
Legal disclaimer
- To the original owner on eligible equipment for eligible residential applications. Warranty period is 5 years if not registered within 90 days. Jurisdictions where warranty benefits cannot be conditioned on registration will automatically receive a 10-year parts limited warranty, which can be changed to the 5-year parts, plus a 3-year labor option on eligible equipment within the first 90 days after installation. The 5-year parts, plus 3-year labor warranty option is available only if the installing dealer/contractor has elected to participate in the Consumer Choice warranty program and has accepted the Consumer Choice dealer terms and conditions.