The industry standard is a Manual J load calculation, which accounts for your home's square footage, insulation, windows, ceiling height, climate zone, and occupancy. As a general rule, most homes need 20–25 BTU per square foot. Use our HVAC Sizing Calculator for a fast, detailed estimate based on your specific inputs.
A full HVAC replacement (AC + furnace) for a 2,000 sq ft home typically runs $6,000–$15,000 installed, depending on the system type, efficiency tier, ductwork condition, and your region. Mini-splits run $2,800–$8,000 per zone. Get a precise estimate with our Replacement Cost Calculator.
SEER2 (Seasonal Energy Efficiency Ratio 2) is the updated efficiency standard that took effect January 1, 2023. It uses a more realistic external static pressure test condition, making it slightly harder to achieve than the old SEER test. A new 14 SEER2 unit is roughly equivalent to an old 15 SEER unit. When comparing older and newer systems, be aware of this scale difference.
It depends on your climate and utility rates. Heat pumps are 2–4× more efficient than gas combustion, but their efficiency drops in very cold weather (below 15–25°F). In mild to moderate climates with average electricity rates, heat pumps typically cost less over 10–15 years. In cold climates with cheap gas, gas furnaces often win on long-term cost. Use our Heat Pump vs. Furnace Calculator to compare for your specific utility rates.
The federal minimum as of 2023 is 14 SEER2 in the South and Southwest and 13 SEER2 elsewhere. For most homeowners in moderate climates, 16–18 SEER2 offers the best payback period. In hot climates with high electricity rates (FL, TX, AZ), 20+ SEER2 may pay off in 7–10 years. Use our SEER2 Savings Calculator to model your specific scenario.
Central AC units typically last 15–20 years. Gas furnaces last 15–25 years. Heat pumps average 10–15 years (they run year-round, so they cycle more). Ductless mini-splits last 15–20 years with proper maintenance. Annual filter changes and biennial professional tune-ups extend life significantly.
Square footage is a starting point, not a final answer. Climate zone, insulation quality, ceiling height, window count, and sun exposure can change your required tonnage by 30% or more. Our HVAC Sizing Calculator factors in all of these variables. For a definitive answer, always request a Manual J load calculation from your contractor.
A ductless mini-split system has an outdoor condenser connected to one or more indoor air handlers ("heads") via refrigerant lines — no ductwork required. They're ideal for homes without existing ducts, room additions, garages, workshops, and situations where you want zone-by-zone temperature control. They're generally more efficient than ducted systems and cheaper to install in new additions. See our Mini-Split Sizing Calculator.