I recently added a small in-law apartment to my house and explored several options for heating and cooling the space. Even though the energy demand is small, the pricing from local HVAC contractors was more than I expected, which motivated me to install a Mr. Cool DIY Mini-Split system by myself. Friends who have installed Mr. Cool systems in their own places were very happy with the ease of installation and performance. The company simplifies minisplit installation with equipment bundles that include matched indoor and outdoor units, precharged line sets, a control cable, and several accessories to complete the installation.

The DIY-friendly, precharged, insulated line sets eliminate the need to flare the ends of the lines and the need for a vacuum pump, which is required for conventional refrigerant lines. Special wrench-tightened couplings at the ends of the line sets form leak-free seals with mating couplings at the indoor and outdoor units. Mr. Cool bundles range in size from 9000 Btu to 36,000 Btu for single-split packages and 18,000 Btu to 64,000 Btu for multisplits with both wall-hung and ceiling-cassette indoor units available. The precharged line sets included with the equipment bundles are either 16 ft. or 25 ft. long.

No vacuum pump needed. Precharged line sets with quick-connect fittings make it easy to install Mr. Cool Mini-Split ductless air-conditioning and heat pump systems without special refrigeration tools or training.

Line sets can’t be cut, so if your outdoor unit is closer than the lines, the company recommends coiling the excess behind the outdoor unit. If the distance between your outdoor unit and your indoor unit is greater than the bundled line set length, extra precharged lines and couplers are available to bridge the gap. You’ll need to supply an electric branch circuit and wall bracket or ground base for the outdoor unit, miscellaneous hardware, and a line set cover (optional).

The quotes I received were in the neighborhood of $4000, including the installation of a new electrical circuit. I spent about $1300 on the Mr. Cool equipment and four-and-a-half hours on the installation. I spent another $150 in electrical materials and three hours running a 20-amp circuit and disconnect. I’m pleased with the ease of installation and performance. You can find out more and locate retailers at mrcool.com.

— Mike Guertin; editorial advisor

From Fine Homebuilding #324

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