Is the Daikin Aurora 9k a cold-climate unit?+
Yes. Daikin gives a -13°F floor, and NEEP certifies 10,900 BTU at both 47°F and 5°F with a COP of 1.8. It holds its capacity in the cold, which suits a bedroom or small office in a northern home.
Why is the efficiency lower than the Mitsubishi FX09?+
Aurora is rated 21.0 SEER2 and 10.2 HSPF2 against the FX09's 33.1 and 13.3. The Aurora costs about $2,155 against about $2,930. The Mitsubishi runs cheaper and reaches -22°F, while the Daikin saves roughly $775 up front.
What does the 12-year warranty cover?+
It is a 12-year limited parts warranty with online registration. It is parts only, so labor after the first year falls on you, although retailers list extended labor coverage for registered installs; confirm terms with your contractor.
Should I install it myself?+
Treat it as a licensed-installer system. Extended coverage is tied to professional installation, the lineset is 1/4" x 3/8" precharged to 49 ft, and R-32 is an A2L mildly flammable refrigerant.