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.
How Our Multi-Zone DIY Builder Works
We’ve made it simple — build the perfect MRCOOL DIY Multi-Zone System in just a few clicks.
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1
Choose Your Air Handlers
Select the indoor units for each room — available in 6k, 9k, 12k, 18k, 24k, and 36k wall mounts, plus 6k, 9k, 12k, and 18k ceiling cassettes. Mix and match sizes and styles to fit your exact layout.
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2
We Pick the Right Condenser
No guessing required. Our builder automatically pairs your chosen air handlers with the correct MRCOOL DIY condenser based on total BTUs and number of zones.
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3
Select Line Set Lengths
Choose the available pre-charged line set lengths for each air handler. Need extra length? DIY couplers and matching control wire are automatically bundled — so there’s no confusion and nothing extra to calculate.
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4
Add Accessories (Optional)
Finish your system with wall brackets, line set covers, surge protection, condensate pumps, and install kits — everything you need for a clean install.
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5
Review & Checkout
Double-check your room selections, line set lengths, and accessories. Once ready, complete checkout and we’ll schedule your LTL freight delivery.
Why Our Builder is Different
Unlike other systems, the MRCOOL DIY Multi-Zone lets you mix wall mounts and ceiling cassettes, combine different BTU sizes, and still install it all yourself with pre-charged line sets. No special tools. No confusion. Just plug, play, and save.
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.
