Installation and replacement. The company you're matched with sizes a new
system from a load calculation on the house, not the tonnage on the old nameplate, and quotes it
in writing before anything is ordered. Dove Mountain is in the Town of Marana, so its permit rules apply rather than the City of Tucson's; the contractor confirms them and pulls the permit. A first replacement of builder equipment should be sized from a fresh load calculation rather than copied from the original nameplate. Pima County lists Trico Electric Cooperative as serving this part of the metro, so check whether your bill says TEP or Trico before counting on a TEP Efficient Home rebate. If your HOA reviews exterior equipment, its architectural committee may need to approve a change to the outdoor unit first.
Heating. At about 2,700 feet, Dove Mountain is valley-floor desert where Pima County's code winter design temperature is 35F, so heating duty is light. A heat pump is the sensible default here: the area needs about 2.6 cooling degree days for every heating degree day, so the same unit does the cooling you need anyway.
Maintenance. A tune-up before the first 100F day covers the coils, refrigerant
charge, electrical connections, capacitor and condensate drain, and a second look after the
monsoon clears the dust. Newer systems mostly need clean coils, the right refrigerant charge and clear condensate drains to reach their second decade in good shape.
Check any contractor's license with the Arizona Registrar of Contractors at roc.az.gov. Residential air conditioning and heating work falls
under the R-39 class. The service pages below go straight to the job you need.