Replace both at once when the units are old and matched parts matter, and replace one alone when the other is young and compatible. Climate Pros Tucson can match you with a licensed pro who checks that fit.

Why do the two get replaced together?

In a split system, the furnace or air handler and the outdoor unit work as a pair. A new outdoor unit paired with an old indoor coil or blower may not reach its rated efficiency, and the pro should confirm compatibility. Replacing both also means one permit and one round of duct, wiring and drain work. The City of Tucson requires permits and load calculations for new and replacement furnaces, heat pumps and ACs, and the pro pulls them. Inside City of Tucson limits, the City’s fee schedule effective July 1, 2026 lists a $150 trade permit for an air conditioner or heater repair or replacement, and $150 for the first item plus $50 for each additional item when one trade permit covers two or more (checked October 2026). The fee belongs on the contractor’s written quote.

When can you replace just one?

  • The other unit is young and the pro confirms the two will match.
  • The failed unit is the only one with a problem.
  • Budget forces a staged plan, with the pro mapping out what comes next.

Ask the pro to write down whether the new part will work with the existing one, and what warranty terms apply to the mix.

Gas pack, split system or heat pump?

Tucson homes use several arrangements. A gas pack (a rooftop or ground package unit with a gas furnace and AC in one cabinet) is one. A split system with a furnace inside and a condenser outside is another. Our guide to split vs rooftop package units compares them.

A heat pump is the sensible default for a Tucson basin home. The airport sees about 2.6 cooling degree days for every heating degree day, and fewer than 12 nights a year at or below 32F, so heating duty is mild and one unit can handle both jobs. Statewide, Arizona homes use central furnaces as main heat in about 55% of cases and central heat pumps in 25% (EIA, 2020), so both are common. Southwest Gas supplies natural gas in the area; electricity comes from TEP or Trico depending on your address.

What about rebates?

Federal 25C ended for installs after 2025. As listed by TEP in October 2026, the Efficient Home program offers up to $720 for a heat pump quality installation and up to $600 for an AC quality installation through participating contractors, applying when you retire an older working unit or a non-working AC. Confirm with TEP.

What do national cost guides list?

HomeGuide lists $5,000 to $11,000 for an HVAC replacement that includes a new furnace and AC unit, and HomeAdvisor lists $5,000 to $12,500 to install or replace an HVAC system, as national figures (checked October 2026). Neither is a Tucson price. The written quote from the pro is the number that counts for your home.

What should a quote say?

  • Load calculation, not a size guess.
  • Exact models of each piece.
  • Duct, electrical and gas scope.
  • Who pulls the permit.

See gas furnace to heat pump conversion, dual fuel heat pumps and our AC installation service. The Tucson HVAC hub lists the areas we cover.

When to call us

Call (520) 353-2520 and we’ll match you with a licensed local pro. Tell the pro the age of both units.