HVAC decision guides
Four decisions drive nearly all HVAC spending: repair or replace, heat pump or furnace, which efficiency tier, and whether to fix the ducts before buying new equipment. Age is the strongest signal for the first one - Carrier puts furnaces at 15 to 30 years and AC and heat pumps at 15 to 20, and suggests replacement when repair costs approach half the value of new equipment.
For repair versus replace, combine three inputs: system age, the repair estimate, and how much longer you'll own the house. HVAC Project Cost describes a common heuristic - multiply age by the repair estimate, and if it exceeds $5,000, replacement usually wins. Use it as a sanity check, not a rule.
For heat pump versus furnace, ask each contractor for an annual operating cost estimate using your actual utility rates. That number, not a general claim about heat pump efficiency, is what determines the outcome for your house.
For duct work, the honest answer is that fixing bad ducts often delivers more comfort per dollar than upgrading the equipment tier. If a contractor recommends a premium system but hasn't measured static pressure or airflow, they are guessing about the part of the system that actually delivers the air.
Choosing HVAC between the options
The judgement calls that decide the bill, before anyone quotes you.
- Anchor on system age first Carrier: furnaces 15 to 30 years, AC and heat pumps 15 to 20. A large repair on equipment past that window is usually a bad bet.
- Ask for operating cost, not efficiency marketing Estimated annual running cost at your utility rates, for each option you're considering. Then compare against the price difference.
- Decide how long you're staying before you pick a tier Efficiency premiums pay back over years. If you're moving soon, that payback largely doesn't happen.
- Fix airflow before buying more capacity Uneven temperatures are usually a duct problem. A bigger unit will not fix them and may make humidity worse.
- Never let a same-day discount make the decision Any decision at this price level deserves at least 24 hours and three comparable written bids.
All HVAC decision guides
Decision Guides 2
Decision Guide 3
HVAC Repair vs Replace
HVAC DIY vs Pro
HVAC Budget vs Premium
Where these figures come from
Sources last checked
- Carrier - How Long Do HVAC Systems Last? · retrieved 2026-07-25
- HVAC Project Cost - HVAC Replacement Cost 2026 · retrieved 2026-07-25
- ACCA - Technical Manuals · retrieved 2026-07-25
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