MRCOOL DIY Mini Split Buying Guide: Everything You Need to Know

The MRCOOL DIY series is the most popular ductless mini split system for homeowners and contractors who want a professional-grade system without the complexity of traditional installation. This guide covers everything you need to make the right choice.

MRCOOL DIY 3rd Gen vs 5th Gen: What's the Difference?

The 5th Generation MRCOOL DIY systems feature improved SEER2 ratings, enhanced cold-climate performance (down to -13°F), and the new SmartHVAC app with advanced scheduling. The 3rd Gen remains a solid, cost-effective option for moderate climates.

Feature	DIY 3rd Gen	DIY 5th Gen
SEER Rating	Up to 22 SEER	Up to 22 SEER2
Min Operating Temp	5°F	-13°F
Refrigerant	R-410A	R-454B
App Control	SmartHVAC	SmartHVAC Enhanced
Pre-charged Line Set	Yes	Yes

How to Size a MRCOOL DIY System

The general rule is 20 BTU per square foot. A 500 sq ft room needs a 12,000 BTU (1-ton) system. A 1,000 sq ft space needs a 24,000 BTU (2-ton) system. Always account for ceiling height, insulation quality, and local climate.

Shop MRCOOL DIY Systems

Browse our full selection of MRCOOL mini splits including single-zone, multi-zone, and universal series systems.