In a city where the average January low is 41°F, a gas furnace runs far fewer hours than one in a cold climate. That makes the replacement decision different: efficiency upgrades pay back slowly, but safety and reliability still matter on the nights that drop toward freezing.
When replacing makes sense
- The heat exchanger is cracked or corroded (found during a heat exchanger inspection).
- The furnace is over 20 years old and needs a major part such as an inducer motor or control board.
- You are replacing the air conditioner and the furnace is the same age; replacing both at once avoids a mismatched system and a second installation.
- The blower is noisy or weak and the furnace also serves as the air handler for your AC.
Where Chandler furnaces live
Attic installs are common in two-story homes. Attics above 130°F in summer are hard on blower motors and control boards, and flue pipes need secure connections and clearances. Closet and garage installs are easier to service but need proper combustion air.
Efficiency choices
An 80% furnace vents through a metal flue and is the usual like-for-like replacement. A 95%-plus furnace vents through plastic pipe and produces condensate, which must be drained; in an attic that adds a drain line and pump in some cases. In Chandler’s short heating season, the extra cost of high efficiency takes longer to recover.
Permits
The City of Chandler’s Homeowner’s Building Permit Manual (revised April 2026) lists like-for-like residential furnace replacement as exempt from permit. Changes to gas piping, venting or electrical, or switching equipment types, can still need permits. Ask the city’s Plan Reviewer of the Day at 480-782-3078 if unsure.
Consider a heat pump
If your AC is due too, a heat pump can replace both. See heat pump replacement in Chandler.
Need a new furnace? Call 480-719-8109 — a real person in the East Valley answers.