MRCOOL DIY Mini Split: Ductless HVAC You Install Yourself
MRCOOL DIY mini splits are ductless heating and cooling systems engineered for homeowner installation without professional HVAC tools or refrigerant certification. They are the only widely available mini split brand with pre-charged, quick-connect refrigerant lines that eliminate the need for vacuum pumps, manifold gauges, and EPA 608 certification. This DIY-friendly design has made MRCOOL the fastest-growing ductless HVAC brand in the residential market.
How a Mini Split Works
A mini split system has two main components. The outdoor condenser (compressor unit) sits outside your home, similar to a traditional AC condenser. The indoor air handler mounts high on an interior wall and distributes conditioned air directly into the room. Pre-charged copper refrigerant lines connect the two units through a small 3-inch hole in the wall. Unlike central HVAC systems, mini splits do not use ductwork, which eliminates duct losses (typically 25% to 30% of energy in ducted systems) and allows zone-by-zone temperature control.
Why “DIY” Changes Everything
Traditional mini split installation requires an HVAC technician to braze copper refrigerant lines, evacuate the line set with a vacuum pump, charge the system with refrigerant, and leak-test the connections. This professional installation typically costs $1,500 to $3,000 per zone. MRCOOL DIY systems eliminate these steps with pre-charged line sets that use quick-connect fittings. The homeowner routes the line set through the wall, connects the fittings by hand (no brazing or flaring), and the system is ready to operate. The only professional work needed is the dedicated 240V electrical circuit, which requires a licensed electrician.
Available Sizes
MRCOOL DIY mini splits are available in multiple capacities matched to room and zone sizes. A 12,000 BTU unit cools and heats rooms up to approximately 500 square feet, ideal for bedrooms, home offices, and bonus rooms. An 18,000 BTU unit covers up to approximately 750 square feet, good for large living rooms, master suites, and open-concept areas. A 24,000 BTU unit covers up to approximately 1,000 square feet, suitable for great rooms, finished basements, and large open spaces. A 36,000 BTU unit covers up to approximately 1,500 square feet, used for whole-floor or multi-room coverage. IB Lighting carries the MRCOOL DIY lineup. Browse all models at our MRCOOL product page.
Heating and Cooling in One Unit
Every MRCOOL DIY mini split is a heat pump, meaning it provides both cooling in summer and heating in winter from a single system. In cooling mode, it works like an air conditioner, extracting heat from indoor air and expelling it outside. In heating mode, the process reverses: the system extracts heat from outdoor air and moves it inside. MRCOOL models operate efficiently in heating mode down to outdoor temperatures as low as -13F to 5F depending on the model, making them viable for most U.S. climates.
Energy Efficiency
MRCOOL DIY mini splits achieve SEER2 ratings of 20 to 22 (depending on model), which is significantly more efficient than most central AC systems rated at 14 to 16 SEER2. This translates to 25% to 40% lower energy costs for the zones served by the mini split compared to conventional HVAC. The inverter-driven compressor adjusts speed continuously rather than cycling on and off, maintaining more consistent temperatures with less energy waste.
Common Applications
MRCOOL DIY mini splits are ideal for room additions and conversions that are not connected to existing ductwork, for garages, workshops, and outbuildings that need climate control, for sunrooms and three-season rooms, for finished basements and attics, for supplemental cooling in hot rooms that the central system cannot keep comfortable, and for homes replacing window AC units with a permanent, efficient solution.
Browse the MRCOOL DIY lineup at IB Lighting or call (800) 674-9019 for sizing recommendations. All MRCOOL systems ship free with freight insurance included.