Estimated to Ship in Early August
Air Handler BTU
- Determine the square footage of the area you want to cool or heat.
- Consider insulation and climate. If the room has poor insulation or is in a particularly hot or cold climate, you might need a higher BTU rating to compensate.
Coverage Area:
- 6000 BTU | up to 250 SqFt
- 9000 BTU | 275 to 375 SqFt
- 12,000 BTU | 350 – 550 SqFt
- 18,000 BTU | 550 – 800 SqFt
- 24,000 BTU | 800 – 1050 SqFt
- 36,000 BTU | 1050 – 1550 SqFt
Ceiling Cassette only comes in 6k, 9K, 12K and 18K
This is the distance between the indoor unit (air handler) and the outdoor unit (condenser).
Zones
A zone makes up an area that you'd like to cool and heat. Generally, a zone is equivalent to an area that is enclosed, such as a kitchen, living room, bedroom or garage.
Each line set length you choose includes the appropriate control wire. No need to calculate wire separately — it's already bundled in with your chosen line set for convenience, compatibility, and cost savings.
Our customizer allows you to mix and match wall-mounted or ceiling cassette air handlers and pair them with a single multi-zone condenser. Choose 2 to 6 zones, select the right BTU for each room, and let our system handle the configuration.
A multi-zone system allows for individualized temperature control in different rooms or floors using a single outdoor unit. It’s energy-efficient, cost-effective, and offers year-round comfort with both heating and cooling capabilities.
Yes! Our customizer supports combinations of ceiling cassette air handlers and wall-mounted air handlers, giving you the flexibility to match different room aesthetics and installation needs.
Nope — MRCOOL DIY systems are designed for homeowner, handyman or contractor installation. With pre-charged line sets and easy-to-follow instructions, you can install your system without needing a licensed HVAC technician.
At MRCOOL DIY Direct, our 5th Gen Multi-Zone systems are the easiest way to control comfort throughout your home. Our systems support 2 to 6 zones on a single condenser with total capacities ranging from 18,000 to 61,000 BTU. Choose from wall-mounted air handlers and ceiling cassettes in sizes from 6k to 36k BTU per zone—all designed for true DIY installation.
Why Homeowners Choose MRCOOL DIY Multi-Zone Systems
- Fully DIY Pre-Charged Systems: No vacuum pump, no special tools, no EPA license required
- Supports 2–6 Zones: Flexibly heat & cool individual rooms or entire floors
- New R-454B Refrigerant: Eco-friendly & 2025 EPA compliant
- Quick Connect® Line Sets: Factory pre-charged with easy connection design
- Extended Warranties & Financing: Optional protection plans and monthly payment options available
How to Size Your MRCOOL Mini Split System
Our zone builder allows you to pair multiple air handler sizes to reach your desired capacity. Here's a general BTU sizing guide:
- 6k BTU – ~200–300 sq ft
- 9k BTU – ~300–450 sq ft
- 12k BTU – ~450–600 sq ft
- 18k BTU – ~600–1,000 sq ft
- 24k BTU – ~1,000–1,300 sq ft
- 36k BTU – ~1,300–1,700 sq ft
Need help? Try our BTU Sizing Calculator or contact us for expert assistance.
Frequently Asked Questions
Can I mix wall-mounted and ceiling cassette units?
Yes! You can mix and match both styles across any zone combination for 2 to 6 rooms.
Do I need a licensed HVAC installer?
No! These systems are built for homeowners with no HVAC license or refrigerant handling certification required.
What kind of refrigerant is used?
All 5th Gen systems use R-454B, which is more efficient and meets new environmental standards for 2025.
How long is the warranty?
All systems include a 5-year parts and 7-year compressor warranty, with optional extended protection available.
