Six factors decide it: correct sizing based on a load calculation, efficiency rating versus your actual run hours, system type, the condition of your existing ductwork, budget including operating cost, and any indoor air quality needs. Sizing matters more than any other item on that list.

1. Sizing Comes First

An oversized air conditioner cools the air fast, satisfies the thermostat, and shuts off — short cycling that wastes energy, wears components, and leaves rooms uneven. An undersized one runs constantly and never catches up on a 100-degree day. The right answer comes from a Manual J load calculation that accounts for square footage, ceiling height, window area and orientation, insulation levels, and Albuquerque’s elevation — not from matching whatever tonnage the old unit happened to be.

2. Efficiency Ratings Worth Paying For

SEER2 for cooling, AFUE for gas heating, HSPF2 for heat pumps. Higher ratings cost more upfront and save monthly. With Albuquerque’s long cooling season, higher-efficiency cooling equipment usually pays back; on the heating side, our relatively mild winters make the premium for a top-tier furnace a closer call.

3. System Type

  • Central AC plus gas furnace — the conventional pairing, strong performance in both extremes
  • Heat pumps — one system for both seasons, very efficient in our mild shoulder months
  • Hybrid fuel — heat pump for most of the year, gas furnace when it gets genuinely cold
  • Ductless mini-splits — for additions, casitas, and older homes without ductwork
  • Evaporative cooling — cheap to run in our dry climate, though it struggles during monsoon humidity

4. Your Ductwork

New equipment on leaky, undersized ducts underperforms immediately. Duct leakage into an unconditioned attic can waste a large share of what you paid for. Evaluate and seal before, not after.

5 and 6. Budget and Air Quality

Weigh purchase price against operating cost over 15 years, and factor in financing. If anyone in the house has allergies or asthma, plan filtration, purification, or humidification into the design rather than bolting it on later.

Contact B. Carlson for a load calculation and honest options in Albuquerque or Santa Fe.