Della has 4 systems in the catalog, priced from ~$770 to ~$1,250. The one that keeps heating coldest is the Della Optima Pro CloudAir 12,000 BTU (25 SEER2) (rated to -22°F). The cheapest way in is the Della Motto 12,000 BTU at ~$770.
Della · Single-Zone
~$1,250
Cold-climate buyers who want a lower price than the NEEP-listed brands and will accept the maker's own claims about cold-weather output until certified numbers exist.
Della · Single-Zone
~$780
Buyers with a 230V circuit who want more efficiency and a lower heating floor than Della's 115V units, and are comfortable doing a flare-and-vacuum install.
Della · Single-Zone
~$770
Value-focused cooling for bedrooms and offices in moderate climates.
Della · Single-Zone
~$850
Budget buyers who already own (or will rent) a vacuum pump and want maximum cooling per dollar over install convenience.