MRCOOL Signature 42K BTU 3.5 Ton 14.3 SEER2 Air Conditionar Condenser and Multi-Position Air Handler (M42C21AA4T4221AC)

The MRCOOL® Signature Series 42k Cooling Only Condenser is built to provide reliable, energy-efficient cooling for homeowners who want dependable performance and lower utility bills.

With a 14.3 SEER2 and 11.7 EER2 rating, this system offers consistent comfort while keeping energy consumption in check, making it a great fit for both replacement projects and new installations. Pre-charged with environmentally friendly R-454B refrigerant, this unit complies with modern environmental regulations while maintaining strong cooling capacity and dependable performance. At the heart of the system is a durable scroll compressor, engineered to deliver steady, reliable operation over time with minimal wear. To further enhance performance, the unit is equipped with inner-groove copper tubing, which maximizes surface area and significantly improves thermal conductivity and heat transfer efficiency. Despite its robust output, the system is designed with noise reduction in mind, operating at a low 65 decibels, comparable to the sound of a household dishwasher. A sound-dampening top minimizes operational noise without limiting airflow, making this unit ideal for installation in residential areas where quiet performance is valued. For added durability, it features a steel louver coil guard and wire fan discharge grille, which offer strong protection for critical internal components.

The unit’s compact, lightweight design makes it easy to position in tight spaces, while thoughtful service-friendly features like sweat connection valves and an easy-access gauge port streamline both installation and ongoing maintenance. To top it off, MRCOOL® offers a 10-year limited parts warranty and a limited lifetime compressor warranty, offering dependable protection and lasting value.

The MRCOOL® Signature Series 42k Multi-Position Air Handler is built to provide consistent, energy-efficient comfort in any climate.

Designed for flexibility and performance, this unit works with R-454B refrigerant, a low-GWP alternative that helps reduce environmental impact without sacrificing power or reliability. Its multi-position design allows for installation in upflow, downflow, or horizontal configurations, making it ideal for a variety of home layouts, from new construction to tight retrofits. With its slim, space-saving profile, it fits easily into closets, attics, or crawl spaces while still delivering full-capacity heating and cooling when paired with a compatible condenser or heat pump. Engineered for durability, the air handler includes a galvanized steel cabinet, a high-efficiency ECM blower motor, and copper “A” coils with enhanced aluminum fins for superior heat transfer and humidity control. Thermal insulation inside the cabinet reduces energy loss and prevents condensation, contributing to quiet operation and lower energy bills. Installation is fast and simple, helping to minimize labor time and disruption. An air filter rack allows for easy maintenance, while an optional electric heat kit is available for added heating performance in colder regions.

Smart home compatibility comes standard, with support for most third-party thermostats so you can manage comfort on your terms; no proprietary systems required. Protected by a 10-year limited parts warranty, the MRCOOL® Signature Series 42k Multi-Position Air Handler offers long-lasting performance, space-saving design, and year-round efficiency for today’s comfort-conscious homeowner.