Question! What kind of heat pumps are being used, air to air, or ground to air? Also do you have any data/idea on relative temperatures? We have an air to air heat pump for a home at 3600 ft. in northern CA and it holds house ,1500 sq. ft, temp at 69-70F down to about 32-35 degrees.
Don’t ask ME! I live in Alaska! But when I lived in St. George, all the homes had heat pumps on the roofs. Very common. Look them up online and you should be able to find out everything you are interested in.