HVAC in Tucson is a split personality. A great many older houses still cool with an evaporative cooler on the roof, and that machine works because the air is dry and the nights drop. It struggles when the monsoon raises humidity and the pads smell, the blower throws damp air, and the indoor temperature will not fall. Newer houses and renovated houses use refrigerated cooling, closer to a Valley system, but they still get a night recovery Phoenix often misses. Winter is a modest heating season, firmer in the foothills, usually a furnace or a heat pump rather than a months-long crisis.
Say which machine you have before you describe the misery. Cooler calls are pads, pumps, belts, curbs, and whether the water is flooding the roof. Refrigerated calls are no cooling, weak cooling, a frozen line, or a noise at the condenser. A clogged filter full of monsoon dust can imitate a dying compressor. Ask what gets ruled out first. A water stain under a cooler is often the curb or the supply line, which means the roof trade and the cooling trade may both be in the sentence. Say that plainly.
If the house is cold on a foothill morning, say so, and say whether the heat is gas, electric, or missing entirely. Wall heaters and floor furnaces still hide in older central houses. Ask whether a replacement would be a matched system and whether the ducts, if any, are worth keeping. Many cooler houses have no duct system at all, so a change to refrigerated air is not a swap, it is a different house. Ask that question directly instead of assuming a pad size.
Maintenance follows the season. Pads and a bleed line before the dry heat, a look at refrigerant equipment before June, and a heat check before the colder foothill nights. If the house is miserable now, do not wait for the calendar. Name the equipment on the roof. Call the number on this page.