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What’s Involved in the Installation of a Ductless System?

A ductless heat pump system is far from the conventional forced-air heat pump in terms of air distribution, efficient zonal comfort and installation best practices. To maximize the benefits of your new system, however, make sure the ductless installation is performed by an HVAC dealer experienced with the intricacies of installing ductless components.

Consulting a Professional Ductless Installer

Ductless systems have been widely used around the world for decades, but their popularity and application for U.S. residential purposes has only occurred in more recent years. With this in mind, you must be finicky when it comes to choosing an HVAC dealer who knows the ropes regarding ductless installation.

Mitsubishi Electric contractors are proven heating and cooling professionals who have undergone factory-approved training for ductless installation best practices and have earned licensing to install ductless systems designed by Mitsubishi Electric -- the inventor of ductless technology.

Rest assured that when you ask your Mitsubishi dealer for proof of appropriate references, licensing, bonding and insurance, the dealer will confidently verify and validate their ability to offer you the best installation and customer service available.

System Sizing and Selection

The fundamentals of ductless installation begin with system sizing and selection. This is where many contractors go awry. Heating and cooling systems, whether ductless, forced air or otherwise, must be accurately sized to the load of the home or zone in which it's installed. Many contractors size systems based solely on the square footage of the home or zone and intentionally over-size systems to be on the safe side.

The notion that over-sizing a system has no adverse consequences for comfort and efficiency and is in fact beneficial is false. The only ductless system that reaches peak efficiency, no matter its make or model, is a right-sized system. Dozens of measurements and calculations must be performed which adhere to the Air Conditioning Contractors of America’s (ACCA’s) Manual J. Then an accurate assessment of the information determines the correct ductless system size.

Installing the Outdoor Unit

The outdoor unit of a ductless system contains the compressor, condenser, blower and other components. It may be mounted to a firm surface, such as a small concrete slab, paver stones, reinforced rubber pads and the home’s exterior wall. The outdoor unit needs at least three feet of clearance from any possible airflow blockages, such as walls, fencing and thick shrubbery.

If you're located in a region of the U.S. that sometimes or often receives heavy snowfall during the heating months, it is better to protect the outdoor unit from snow and ice accumulation with a small awning or overhang that doesn't obstruct airflow. If the ductless installation is for a cooling-specific unit (i.e. not a heat pump), your HVAC dealer doesn't need to consider these special installation points for the heating months.

Installing the AHU

One of the many attractive features of ductless systems is the versatile mount options of the indoor air handling unit (AHU). The most common mount is universal mount to the ceiling, high- or low-wall mount or using special brackets to install the AHU on the floor. Whether ceiling, wall or floor mount, the AHU is affixed to the surface, which allows easy access to air filters and interior components for cleaning.

Ductless systems are accommodating to practically any type of interior design and space. Your HVAC dealer should be skilled with concealed installation, which locates the AHU in the cavity above, behind or below the ceiling, wall or floor, respectively. The only component visible from the living spaces is the flat supply outlet.

Another popular AHU mount is ceiling or wall recessed. This is a nice compromise between universal, which also allows easy access to parts and a low-profile mount similar to the concealed option. Whichever mount option best serves your project, make sure your HVAC dealer explains optional airflow enhancements for optimal heating and cooling.

Installing the Conduit

A ductless system is comprised of three basic components which house all the parts: the outdoor unit, the indoor AHU and a thin conduit. The conduit is really the component that makes ductless systems, after all, ductless. The conduit houses the refrigerant lines, condensate tubing and power source. The conduit connects to the components of the outdoor and indoor units, and it's routed through walls, crawl space and other inconspicuous areas out of sight of the living spaces.

For more tips on ductless installation best practices, please contact us to speak with a Mitsubishi Electric contractor near your home.

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