Cited facts
Replacement-cost median
$5,650
ProFix Real Cost Index permit median; national (United States); IQR $2,800-$10,590; n=330,437 permits.
Open Real Cost IndexRepair or Replace?
A broken home system does not need a fake verdict. This tool lines up the facts: your repair quote, the live Real Cost Index replacement median, the cited InterNACHI lifespan, DOE HVAC age guidance where it applies, and what each industry rule of thumb says.
Live Real Cost Index mediansInterNACHI-cited lifespansDecision support only
Check the facts side by side
This tool shows decision-support signals, not a verdict.
Decision-support summary
The numbers are mixed. Use the signals below to ask sharper questions before approving the repair.
Furnace: $900 repair quote, 14 years.
Cited facts
Typical lifespan
15 years
15-year planning life. InterNACHI lists central air conditioners at 7-15 years and furnaces at 15-25 years; this category uses a 15-year planning denominator.
Source: InterNACHI Standard Estimated Life Expectancy Chart for Homesindustry rule of thumb
50% rule
If the repair would cost more than half of a new system, replacing is usually the better value.
Repair quote as share of replacement median
15.9%
$900 vs. $2,825 threshold: leans repair
Common HVAC-industry rule of thumb, not a single authority. guidance, not a verdict.
industry rule of thumb
$5,000 rule
Multiply age by repair cost; if the score exceeds the threshold, it leans replace.
14 x $900
12,600
12,600 vs. 5,000 threshold: leans replace
Common HVAC-industry rule of thumb, not a single authority. guidance, not a verdict.
Age vs. cited lifespan
93.3%
1 years left before the cited lifespan.
Life expectancyDOE HVAC age guidance
DOE says to consider replacement when this HVAC category is older than 15 years. leans repair.
DOE guidance also notes that replacing a 15+ year system with ENERGY STAR equipment can cut energy use. (20-40%).
U.S. Department of Energy Energy Saver - Air Conditioner MaintenanceWhat the rules are, and are not
The 50% rule and $5,000 rule are common HVAC-industry rules of thumb. They are not facts, not code requirements, and not from a single authority. This page shows what each one indicates for your inputs so you can ask a better contractor question.
Use the adjacent ProFix checks
Frequently asked
Does this tool tell me to repair or replace?
No. It shows decision-support signals: your quote as a share of the Real Cost Index median, equipment age against a cited InterNACHI lifespan, DOE HVAC age guidance where applicable, and two common industry rules of thumb.
Where does the replacement cost come from?
The replacement median is read from ProFix's Real Cost Index using the live trade benchmark. If a benchmark is missing, the tool says no benchmark published and links to the cost index instead of inventing a number.
Are the 50% rule and the 5K rule facts?
No. They are common HVAC-industry rules of thumb, not facts and not from a single authority. They are shown as guidance only.
What can override the math?
Some failures are a replace regardless of cost - e.g. a cracked furnace heat exchanger (carbon-monoxide risk) or major refrigerant/compressor failure - and no rule of thumb captures safety. a licensed pro should make the final call; this is a starting point.