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)
Not a very good product for a home. Blower is not controllable, only runs on max speed. Humidity control doesn’t work properly.
May 10, 2026
Air handler only runs on max fan speed and does control the humidity properly.
Quiet and Efficient Unit
May 3, 2026
Heat pump cools well and runs very quietly, but does not provide as much heat as advertised. The system takes about two degrees beyond what is programmed to activate, resulting in a lapse in performance. Installers were unsure of how to install the system and needed several callbacks to properly complete the installation of the auxiliary heat unit.
Good air handling unit
April 15, 2026
This was part of our HVAC installation and does a very good job as an air handler. In our case, it is limited by the new ductwork installation and this being our first experience with heat pump (vs. gas furnace) technology. I wish I had spent more time with the installers reviewing the ductwork design to ensure adequate airflow to all rooms. However, I am very happy with the Carrier brand and this product.
Compliment to our Carrier heat pump.
March 21, 2026
Works as intended with heat pump and heat strips for below freezing.
Worse product ever!
February 25, 2026
Will not regulate home temperature properly. The Ecobee is useless. Not a reliable produce. Worse heating system that I have ever had. Had to call for repairs 2 -3 times a month.
Quiet air handler
January 24, 2026
Quiet
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.