MRCOOL DIY 4th Gen 36,000 BTU vs MRCOOL DIY 5th Gen 36,000 BTU
Quick take: The MRCOOL DIY 5th Gen 36,000 BTU replaced the MRCOOL DIY 4th Gen 36,000 BTU, which is discontinued.
| Spec | MRCOOL DIY 4th Gen 36,000 BTU | MRCOOL DIY 5th Gen 36,000 BTU |
|---|---|---|
| Price | $2,900 | $3,469 |
| Rating | — | — |
| Type | Single-Zone DIY | Single-Zone DIY |
| Capacity | 36k BTU | 36k BTU |
| Coverage | ~1,500 sq ft | ~1,500 sq ft |
| SEER2 (cooling) | 18 | 18 |
| HSPF2 (heating) | — | 8.5 |
| Low-Ambient Heating | to -13°F | to -13°F |
| Max heat at 5°F (NEEP) | not listed | 22,000 BTU |
| Heat kept at 5°F | — | 61% of rated |
| Refrigerant | R-410A | R-454B |
| Zones | Single zone | Single zone |
| Voltage | 230V | 230V |
| WiFi Control | Built-in | Built-in |
| Install | The biggest quick-connect single-zone MRCOOL makes: precharged 25-ft lineset with 3/8" and 5/8" lines, 208/230V dedicated circuit (40A ampacity, 50A max fuse on this size), and a serious 200+ lb condenser that needs two strong people and a solid pad. The 49-inch air handler dominates a wall — measure twice. | Precharged 25-ft R-454B Quick Connect lineset (3/8" x 5/8"), no vacuum pump, but everything else is big: the condenser is about 152 lb and the 36k is the largest single-zone head MRCOOL sells as DIY. MRCOOL's spec lists a dedicated 208/230V circuit with a 33A minimum ampacity and 35A maximum fuse. Leak sensor rules apply: no expanding foam near the air handler. |
| Warranty | 7-year compressor / 5-year parts with online registration (limited lifetime compressor promo when registered) | 7-year compressor / 5-year parts with registration (MRCOOL DIY Direct also offers an optional lifetime-compressor upgrade) |
Pros & cons
MRCOOL DIY 4th Gen 36,000 BTU
- ✓36,000 BTU from one precharged quick-connect install — no other DIY single-zone goes this big
- ✓Heating rated down to -13°F with 36k BTU output for real winter duty
- ✓Gold Fin coated condenser for corrosion resistance
- ✓Clearance pricing on remaining 4th Gen stock makes cost-per-BTU the best in the lineup
- ✗18 SEER2 is the least efficient unit in the DIY range — higher bills in cooling-heavy climates
- ✗MRCOOL doesn't publish an HSPF2 for this size, making heating-cost comparisons hard
- ✗200+ lb condenser and 49-inch air handler make this a genuinely hard two-person install
- ✗A single head can't evenly condition divided floor plans — expect hot/cold rooms
MRCOOL DIY 5th Gen 36,000 BTU
- ✓36,000 BTU from one precharged quick-connect install, the most of any MRCOOL DIY single-zone
- ✓22,000 BTU at 5°F is the most absolute cold-weather heat in the DIY single-zone line
- ✓Now has an AHRI-certified HSPF2 (8.5), so heating cost can actually be compared
- ✓Precharged lines up to 75 ft make it easier to put the heavy condenser where it belongs
- ✗18 SEER2 and 8.5 HSPF2 are the lowest efficiency numbers in the 5th Gen DIY range
- ✗Keeps only about 61% of rated heat at 5°F, with a 1.97 COP
- ✗Not Energy Star on MRCOOL's spec sheet or cold-climate Energy Star per NEEP
- ✗152-lb condenser and a very long wall unit make this a hard two-person install
- ✗One head can't condition a chopped-up floor plan; closed-off rooms will drift
- ✗Roughly $570 more than the 4th Gen 36k sold for