Pick the DELLA Vario 12,000 BTU 115V if a professional is installing it anyway and you want the newer R-454B refrigerant. Pick the MRCOOL DIY 12,000 BTU 115V if you plan to install it yourself and you're comfortable with the long-proven R-410A design.
The central trade-off
Efficiency. The DELLA Vario 12,000 BTU 115V lists 20.5 SEER2; the MRCOOL DIY 12,000 BTU 115V lists 22 SEER.
Installation. The MRCOOL DIY 12,000 BTU 115V uses pre-charged quick-connect lines for DIY installs; the other needs its lines vacuumed and opened by a technician.
Refrigerant. R-454B in the DELLA Vario 12,000 BTU 115V, R-410A in the MRCOOL DIY 12,000 BTU 115V. New systems moved from R-410A to lower-impact A2L refrigerants in 2025; existing R-410A stock can still be installed.
Noise. The MRCOOL DIY 12,000 BTU 115V lists 23.5 dB indoors at its quietest, against 42 dB.
Side by side
| Specification | DELLA Vario 12,000 BTU 115V | MRCOOL DIY 12,000 BTU 115V |
|---|---|---|
| Cooling (maker) | 12000 BTU | 12000 BTU |
| Heating (maker) | 12000 BTU | Not stated by the maker |
| SEER2 | 20.5 | 22 |
| HSPF2 | Not stated by the maker | Not stated by the maker |
| Heats down to (maker) | Not stated by the maker | Not stated by the maker |
| Voltage | 115 V | 115 |
| Refrigerant | R-454B | R-410A |
| Room size (maker) | 550 sq ft | 500 sq ft |
| Indoor noise (maker) | 42 db | 23.5 db |
| Line set included | Not stated by the maker | Not stated by the maker |
| Warranty | Not stated by the maker | Warranty |
Values are the makers' published specifications. "Not stated" means the maker doesn't publish it.
Which should you choose?
Choose the DELLA Vario 12,000 BTU 115V if
- A professional is installing it anyway
- You want the newer R-454B refrigerant
Choose the MRCOOL DIY 12,000 BTU 115V if
- You plan to install it yourself
- You're comfortable with the long-proven R-410A design
- It's going in a bedroom