The MRCOOL Advantage 18,000 BTU 5th Gen Mini Split and the Pioneer Diamante Pro 18,000 BTU High-Wall Series Ductless Mini Split side by side on one honest scale: cooling, room coverage, noise, energy rating and live price, with which one actually fits your room. Every number is the manufacturer's own or a live retailer price. We never invent a spec.
The verdict
For your 250 sq ft room, neither is an ideal fit: the MRCOOL Advantage 18,000 BTU 5th Gen Mini Split is more cooling than the room needs and the Pioneer Diamante Pro 18,000 BTU High-Wall Series Ductless Mini Split is more cooling than the room needs. On the numbers, the MRCOOL Advantage 18,000 BTU 5th Gen Mini Split is quieter at 50 dB(A), while the Pioneer Diamante Pro 18,000 BTU High-Wall Series Ductless Mini Split is cheaper at $1,138. Compare their specs side by side below, or try a different room size.
![]() MRCOOL Advantage 18,000 BTU 5th Gen Mini SplitSplitSEER2 19.2 In stock $1,399 Buy at Sylvane | ![]() Pioneer Diamante Pro 18,000 BTU High-Wall Series Ductless Mini SplitSplitSEER2 21 In stock $1,138 Lowest since Jul 25, 2026 $1,138 Buy at Sylvane | |
|---|---|---|
| Cooling & fit | ||
| Room fit | More than you need for 23.2 m² | More than you need for 23.2 m² |
| Cooling power | 18,000 BTU · 5.3 kW | 18,000 BTU · 5.3 kW |
| Covers | up to 800 sq ft | up to 750 sq ft |
| Comfort | ||
| Indoor noise | ||
compare.ac may earn a commission on purchases, at no cost to you. It never changes the price you pay or how we rank units.
Both units are scored on the exact same scale, from the manufacturer's own published specs and the live retailer price where we have one. Room fit uses the official ENERGY STAR sizing chart, or an estimate from cooling power when a maker publishes no coverage. Where the two efficiency scales are not comparable, we never crown a winner. Nobody can pay for placement.
Read our full methodologyThe bigger questions behind this comparison, answered from live prices and real specs.
| 50 dB(A)about as loud as a refrigeratorBest |
| 55 dB(A)about as loud as a dishwasher |
| Indoor unit size | Slim | Slim |
|---|
| Efficiency | ||
| Energy rating | SEER2 19.2 | SEER2 21 |
|---|---|---|
| SEER2 (cooling) | 19.2 | 21 |
| Practicalities | ||
| Heats too | Yes | Yes |
|---|---|---|
| Heating output | 18,800 BTU | 19,000 BTU |
| Heats down to | -22°F outdoors | -4°F outdoors |
| Refrigerant | R-454B | R-454B |
| Install | Certified installer ($1,500-4,000 fitted, est.) | Certified installer ($1,500-4,000 fitted, est.) |
| Outdoor unit | Yes | Yes |
| Warranty | Eligible for MRCOOL Care Prgram; 2-Year Compressor Warranty; 1-Year Parts Warranty | 5-Year Limited Warranty |
| Price | ||
| Price | $1,399 | $1,138Best |
|---|---|---|