Why is my AC not working
The most common reasons an AC stops cooling, and how a technician isolates each.
Diagnostic overviewHVAC Guides for NYC Apartments & Buildings
HVAC guides written by the AC Repair NYC team, a licensed contractor based at 517 E 77th St, Manhattan. Each article covers a common symptom, cleaning task or system decision the way we explain it on service calls in Manhattan, Brooklyn and Queens. Written by working technicians, not marketers. Call (212) 201-9201 when the fix is not DIY.
Guides
Troubleshooting
Symptom-first guides for common AC and HVAC problems in NYC apartments and buildings.
AC running but not cooling
Seven causes when the fan runs but no cold air comes out — ordered by likelihood.
No-cool guideAC blowing hot air
Capacitor, refrigerant charge, thermostat wiring and controls — where cool air goes.
Hot air fixAC freezing up (ice on coils)
Ice on coils or refrigerant lines — turn it off first. Then diagnose airflow or refrigerant.
Freeze-up guideAC tripping the breaker
Seven causes, safe DIY checks, and when it's electrical vs an HVAC issue. NYC code notes.
Breaker tripAC making strange noises
Grinding, clicking, buzzing, hissing, screaming — each sound points to a different problem.
Noise diagnosisAC smells bad
Musty, burning, chemical, rotten-egg odors decoded. Which are urgent, which can wait.
Odor diagnosisAC short-cycling
Turning on and off every 3–5 minutes? It's a symptom, not a diagnosis — with NYC context.
Short-cycle fixAC leaking water
Water on the floor: drain pan, drain line, sleeve tilt and pump failures.
Leak diagnosis
Guides
Equipment & buying decisions
Sizing, comparisons, and lifespan for NYC apartments, brownstones and offices.
How to choose the best AC
Sizing, system type and installation constraints for NYC apartments.
Buying guideDuctless mini-split vs central AC
Trade-offs for apartments choosing between a ductless retrofit and central AC.
ComparisonPTAC vs window AC in NYC
Installation, cost, efficiency, noise, and co-op board rules — for NYC condos and rentals.
ComparisonCentral AC vs heat pump
2026 install cost, running cost, LL97 compliance, and NYC winter performance.
ComparisonHow long does an AC last in NYC?
Central AC 12–18 years, window units 6–10, PTACs 8–12, heat pumps 14–20. Real NYC lifespan.
LifespanWhat size AC do I need?
BTU sizing for NYC apartments, brownstones, and offices — Manual J method.
SizingSEER rating explained
SEER2 for 2026 NYC buyers: minimum ratings, payback math, Con Edison rebates.
Efficiency
Guides
Cost & pricing
Real NYC 2026 prices for service, installation, maintenance and replacement.
AC service cost in NYC
What a diagnostic, capacitor swap and refrigerant leak actually cost in New York.
Service pricingAC installation cost NYC 2026
Central $6.5k–$14k, ductless $4.5k–$18k, PTAC $1.6k–$3.2k, window $250–$700 installed.
Install pricingHVAC maintenance cost NYC
Annual tune-up $180–$420. What's included and contract vs one-off pricing.
Maintenance pricingAC repair vs replacement
The $5,000 rule explained for NYC — real 2026 numbers and edge cases.
Decision guide
Guides
Maintenance & seasonal
Cleaning, seasonal prep, and keeping the system healthy year-round.
Central AC maintenance
Annual maintenance tasks for a central AC in an NYC apartment or brownstone.
MaintenanceHow to clean AC coils
Evaporator and condenser coil cleaning steps for apartment central AC and ductless heads.
Coil cleaningHow to clean an AC unit
End-to-end seasonal cleaning from filter to condensate pan.
AC cleaningHow to clean a window AC
Deep clean and reinstall a window AC without wrecking the fins or drain.
Window unitSummer prep checklist
12-step AC pre-season checklist for NYC — filter, coil, condenser, drain, electrical.
Summer prepHVAC winterization NYC
Protecting condensers, heat pumps, and PTACs from NYC winter and salt exposure.
Winter prep
Guides
NYC-specific & commercial
Permits, compliance, landlord duties, and commercial HVAC in NYC buildings.
HVAC for NYC landlords
Repair, maintenance and unit swaps for landlords managing tenant HVAC.
Landlord guideUnderstanding commercial AC
Rooftop units, package systems and PTAC fleets: how commercial differs.
Commercial primerNYC HVAC permits & DOB
What HVAC work requires a DOB permit, who files, and what happens if you skip it.
ComplianceLocal Law 97 and your building
LL97 emissions caps for condo boards, coop owners, and commercial landlords.
LL97 compliance
Editorial policy
About the guides
- Written by working NYC HVAC technicians, edited for accuracy before publishing.
- Prices reflect New York City rates as of 2026, not national averages.
- We say when a task is DIY and when it needs an EPA 608 certified technician.
- No affiliate links; no invented reviews; no aggregated ratings.
- Guides are updated as building rules, refrigerant regulations and equipment change.
- If you spot a factual error, email info@acrepair.nyc and we will look at it.
Get service
Request a quote or call us directly
Prefer to have us handle it? Call (212) 201-9201 or send the symptom and building type via the quote form.
- Address
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517 E 77th St
New York, NY 10075 - Phone
- (212) 201-9201
- info@acrepair.nyc
- Hours
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Monday–Friday 8:00–18:00
Saturday 9:00–15:00
Sunday closed · emergency line answered 24/7 - Service area
- Manhattan, Brooklyn, Queens