UST Air Conditioning is the air conditioning and heating company Hawaii homeowners call when the house is too hot, the mini-split is dripping or the heat pump quits on a cold upcountry night. Same-day air conditioning repair, emergency 24 hour AC repair, new system installation and maintenance on every island.
One company for every heating and cooling problem. Every service also has a dedicated page for each city we serve, so you get local details wherever you are in Hawaii.
Fast diagnosis and repair of any central, split or window air conditioner that is not cooling, leaking, tripping breakers or making noise.
AC RepairProperly sized, correctly charged new air conditioning systems: central air, ductless mini-splits and high-efficiency heat pumps, installed right the first time.
AC InstallationA thorough seasonal tune-up that cleans coils, checks refrigerant charge, tightens electrical connections and catches small problems before they become no-cool calls.
AC Tune-upNights, weekends and holidays: when the air conditioner dies in the middle of a Hawaii heat wave, a live dispatcher answers and a technician is on the way.
Emergency AC RepairRepair of whole-home ducted air conditioning systems, from the outdoor condenser to the air handler, ductwork and thermostat.
Central Air RepairThe most common call we get, solved the same day: a system that runs but cannot bring the temperature down.
AC Not Cooling RepairCompressor diagnostics, hard-start kits, and replacement of failed compressors under warranty or out of warranty, with honest advice on when replacement makes more sense.
AC Compressor RepairProper leak detection, repair and weighing in the correct refrigerant charge for R-410A, R-32 and older R-22 systems.
AC Refrigerant RechargeSingle and multi-zone ductless systems, the most popular way to cool Hawaii homes without ductwork: installation, repair, cleaning and error-code diagnostics.
Mini-split ServiceHeating repair for heat pumps, mini-splits in heat mode, electric furnaces and wall heaters, for the cool nights that upcountry, Volcano and windward homes really do get.
Heating RepairRepair of electric and gas furnaces, air handlers with heat strips and packaged systems: no heat, short cycling, tripped limits and noisy blowers.
Furnace RepairReplacement and new installation of electric furnaces, heat-strip air handlers, wall heaters and heat pump heating for cooler Hawaii elevations.
Heater InstallationA pre-season heating check that tests elements, limits, defrost cycles and airflow so the system is ready for the first cold night.
Heating Tune-upNo heat on a cold night in Volcano, Kula or Waimea is an emergency for families with kids, kupuna or medical needs. We answer 24/7.
Emergency Heating RepairHeat pumps are the ideal Hawaii system: efficient cooling all year and heat when you need it. We repair, maintain and install all major brands.
Heat Pump RepairOne call for any heating, ventilation or air conditioning problem: central systems, mini-splits, heat pumps, ductwork and controls.
HVAC RepairDesign and installation of complete heating and cooling systems for new construction, renovations and worn-out equipment replacement.
HVAC InstallationScheduled maintenance that keeps cooling and heating systems efficient, protects warranties and stops breakdowns during the hottest weeks of the year.
HVAC MaintenanceHeating and cooling repair for single-family homes, condos, townhomes, ohana units and vacation rentals across Hawaii.
Residential HVAC RepairRooftop units, split systems, VRF, walk-ins and make-up air for restaurants, retail, offices, hotels and medical spaces, with maintenance contracts that keep doors open.
Commercial HVACSealing, repair, replacement and cleaning of ductwork so cooled air reaches every room instead of the attic.
Ductwork ServiceSmart and programmable thermostat installation, wiring repair and setup so your system runs efficiently and you can control it from anywhere.
Thermostat ServiceWhole-home dehumidifiers, filtration, UV coil lights and ventilation upgrades that fight the mold, vog and humidity Hawaii homes deal with.
Indoor Air QualityAir conditioners in Hawaii run almost every day of the year in salt air and high humidity. That combination corrodes coils and contactors, clogs condensate drains with algae and feeds mold in mini-split heads. On the Big Island, vog adds fine particulate to the mix; in Kula, Volcano and Waimea, cool winter nights make heat pumps essential.
Our technicians work in those conditions every day. We stock the parts that fail first here, use corrosion-resistant components for coastal homes and size new systems by measuring your home instead of guessing.
Serving all of Hawaii, including these popular areas:
Thermostat was blank and I assumed the worst. Turned out to be the float switch on a clogged drain. Quick fix, small bill, honest explanation.
Chris Y., HawaiiStraightforward pricing, showed up when they said they would, and the office followed up a week later to make sure everything was still working. That is rare these days.
Kawika O., HawaiiThe dehumidifier they installed ended our mold problem in the closets. Air in the house feels completely different and the AC runs less.
Chris Y., HawaiiYes. UST Air Conditioning answers live 24/7 and dispatches emergency technicians on Oahu, Maui, Kauai and the Big Island for no-cool, leaks and electrical problems.
Every city in Hawaii, from Honolulu, Kapolei and Kailua on Oahu to Hilo, Kona and Waimea on the Big Island, Kahului, Kihei and Lahaina on Maui and Lihue and Kapaa on Kauai.
Common repairs are priced from a flat-rate book and quoted before work begins. You will never get a bill that differs from the approved quote.
Yes: Carrier, Trane, Lennox, Rheem, Goodman, Daikin, Mitsubishi, Fujitsu, LG, Gree, Panasonic, York and more.
Homes in Kula, Volcano, Waimea, Makawao and other mauka areas rely on heat pumps and mini-splits in heat mode during winter. We repair and install them.
The five reasons a Hawaii air conditioner runs all day without cooling, what you can safely check yourself and when to call for AC repair.
How trade-wind salt destroys coils, contactors and cabinets, which homes are most at risk, and the maintenance schedule that doubles equipment life.
Ductless mini-splits dominate new installs in Hawaii, but central air still wins for some homes. Here is how to choose.
Exactly what a real AC tune-up includes, what it prevents, and why spring is the time to schedule it.
A practical framework for deciding between another AC repair and a new system, with Hawaii-specific factors like R-22, salt damage and electric rates.
Live dispatchers 24/7. Same-day service in most areas. Flat-rate pricing before work begins.