I am shopping for a new electric heat pump rooftop package in Phoenix. I have consulted three reputable HVAC contractors. Two of them are suggesting R-22 units, and one is suggesting R410. All three contractors have both R-22 and R410 units to offer.
The two contractors suggesting the R-22 units say R410 units run higher head pressures and need more subcooling. These R410 characteristics combined with very high ambient temperatures (especially for rooftop packages sitting on brown roofs) have led to greatly reduced cooling capacities and higher failure rates for R410 units on very hot days.
I e-mailed a few manufacturers asking if R410 was appropriate for the Phoenix area. In all cases the answer was "ask your dealer".
I have read other threads in this forum regarding the R410/R-22 debate, but could not find any information regarding R410's suitability for areas like Phoenix.
If it makes any difference, I am looking for a 4 ton unit with a 13 SEER
Any comments would be appreciated.