If your air conditioner is running but not cooling, start with a few safe checks: confirm it is set to Cool, verify the indoor unit has power, replace a severely blocked filter with the correct type, and clear debris around the outdoor unit. Leave electrical and refrigerant work to a qualified HVAC technician. If indoor heat becomes dangerous or someone shows signs of heatstroke, get them to an air-conditioned place and call emergency services.
Check your AC safely before the heat peaks
Use this sequence for basic checks only. Follow the equipment manual, and do not remove panels or attempt electrical or refrigerant repairs.
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- Check the thermostat and power. Set the system to Cool and lower the setpoint modestly. Confirm the indoor unit has power. The NSW Government advises households to check that fans and air conditioning are working and set the system to cool.
- Inspect the return filter. If a disposable filter is heavily blocked, replace it with one that matches the existing dimensions and is compatible with the system. Do not run the system with a severely blocked filter. EPA guidance emphasizes maintaining filters, vents, and louvers.
- Clear airflow around the equipment. Make sure supply vents are not obstructed. Remove leaves and debris around the outdoor condenser, leaving the clearances specified by the manufacturer. EPA recommends cleaning and trimming around outdoor HVAC units and removing dust and dirt from cooling coils.
- Stop if the problem is beyond routine maintenance. If the unit still blows warm air, trips a breaker, leaks water, makes unusual electrical noises, or may need refrigerant, turn it off if it is safe to do so and contact a qualified HVAC technician. EPA specifically warns against using propane-based “22a” refrigerant in equipment not designed for flammable refrigerants.
For a routine filter change, choose a replacement HVAC air filter only after checking the old filter’s dimensions and your system’s requirements. A filter that does not fit or is incompatible can restrict airflow or fail to protect the equipment as intended.
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Know when heat is a medical emergency
Heat illness can become fatal. The World Health Organization says, “Heatstroke is a potentially fatal medical emergency.” If someone is confused, faints, loses consciousness, or appears to have heatstroke, call emergency services. Move them to shade or air conditioning and apply cold, wet cloths while help is on the way. Do not delay emergency care to troubleshoot the AC.
#1 Best Overall
- 3-in-1 Portable Air Conditioner: Enjoy cool air (64°F- 90°F) during hot summer days, plus dehumidifier and fan modes for comfortable air circulation when temperatures are milder. Everything you need for year-round comfort in one AC unit
- Comfort Sleep Mode: Sleep mode and programmable 1-24 hour timer maintain your ideal room temperature automatically. Ultra-quiet operation below 50dB won't interrupt sleep, while two adjustable fan speeds let you customize airflow
- Quick Window Installation: Comes ready to install with exhaust hose and adjustable window kit that fits widths from 20.48 to 49 inches. No handyman skills required—set up completely in just minutes and start cooling immediately（for small windows, trimming may be necessary)
- No-hassle Maintenance: Advanced Self-evaporating operation effectively reduces the frequency of manual water draining. The washable filter captures dust effectively and slides out easily for quick cleaning whenever needed—keeping air fresher longer
- Room-to-Room Versatility: Lightweight with smooth-rolling casters, this compact AC moves effortlessly wherever cooling is needed. Perfect for bedrooms, living rooms, garages—any space up to 750 square feet
The CDC advises people to use air conditioning or find a location that has it, stay hydrated, check local HeatRisk, and check on older adults, infants, pregnant people, and people with chronic conditions. Plan for refrigerated medicines and medical devices that need electricity if an outage occurs. CDC guidance dated July 20, 2026 is available in About Heat and Your Health.
Use fans only within safe temperature limits
A fan moves air; it does not lower the room’s air temperature. Its safety depends on the actual indoor temperature, not just whether it feels like a breeze. CDC advises using fans only when indoor temperatures are below 90°F. EPA cautions against using electric fans for cooling when rooms are in the mid-90s or hotter, and WHO warns that fans can heat the body when temperatures exceed 40°C.
Rank #2
- Fast, Effective Cooling for Rooms Up to 750 Sq. Ft: This 14,000 BTU portable air conditioner provides rapid spot cooling for spaces like bedrooms, home offices, or apartments up to 750 sq. ft. It helps quickly dissipate indoor heat, keeping you comfortable even on the hottest summer days.
- 3-in-1 Versatility: AC, Fan & Dehumidifier: More than just a cooler, this unit also functions as a dehumidifier and a circulating fan. It reduces excess indoor humidity and improves air circulation, delivering year-round comfort across different seasons and weather conditions.
- User-Friendly Controls & Eco-Conscious Design: The clear LED control panel makes operation easy, with a programmable 24-hour timer and Sleep Mode for convenient, quiet nighttime use. Designed with eco-friendly refrigerant, this energy-efficient AC helps cool your space while minimizing energy consumption.
- Easy to Move with Rolling Casters & Side Handles: Compact and sleek, this unit features smooth-rolling wheels and ergonomic side handles, so you can effortlessly move it from room to room — wherever cooling is needed most.
- Quick No-Drill Window Installation: The package includes a remote control and a complete window installation kit with an adjustable exhaust hose and window panels. Fits most double-hung or sliding windows, requires no drilling, and can be set up in minutes — ideal for renters or temporary cooling needs.
When the room is at or above those limits, do not rely on a fan for cooling. Go to an air-conditioned location instead. Below 90°F indoors, a fan may improve comfort; WHO also suggests using a fan with AC set to 27°C where possible.
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- Shade sun-facing windows. EPA notes that exterior awnings and louvers can outperform interior shades at reducing solar heat gain.
- Close windows while outdoor air is hotter than indoor air; ventilate when conditions outside are cooler.
- Use air conditioning if available. If it fails or your home is too hot, seek an air-conditioned public place such as a cooling center, library, or mall. Availability varies by location, so check local notices.
- Where possible, WHO recommends keeping living spaces below 32°C by day and 24°C at night, and checking indoor temperatures at set times.
For outage planning, identify an air-conditioned place you can reach and make a plan for refrigerated medicines and powered medical devices before the heat arrives. Keep local heat alerts and public cooling-site information handy.
Rank #3
- Three-in-One Unit: Our 14,000 BTU ASHRAE (10,200 BTU SACC) air conditioner also functions as a dehumidifier & fan. This portable air conditioner has a full function remote control & top mounted control panel with LED display
- Portable AC: Take this personal air conditioner (16.5” x 14.06” x 27.09) in rooms up to 700 sq. ft. Stay cool in the hot summer months and sleep well with this BLACK+DECKER ac unit for bedroom
- Smart AC with Voice Control: This smart air conditioner allows Wi-Fi connectivity and can be controlled using our mobile app available on iOS and Google Play stores, and voice controlled by Amazon Alexa or Google Assistant
- Follow Me Remote: Our portable AC unit comes with a full function remote control that features a FOLLOW ME function, which allows the remote to act as a thermostat for precise temperature control
- Installation Kit: When it comes to fans that blow cold air, this indoor ac unit includes an easy-to-install window kit. A large, vented airflow outlet ushers in cool air
Choose cooling equipment for the room and the conditions
| Option | What to compare | Key limitation or requirement |
|---|---|---|
| Portable or room air conditioner | Cooling capacity, room size, energy use, noise, and condensate handling | Check exhaust and installation requirements for the specific model. |
| Central or split air conditioning | Seasonal efficiency, correct sizing, filter access, and serviceability | Installation and sizing may require a professional. DOE FEMP points buyers to ENERGY STAR and CEE-AHRI certified-equipment directories. |
| Fans | Airflow and noise | Use for cooling only when indoor temperature is below 90°F, following CDC guidance. |
| Shades and awnings | Window orientation, installation, and ability to reduce direct sun | Exterior awnings and louvers can reduce solar heat gain more effectively than interior shades, according to EPA. |
DOE FEMP’s guidance on certified central air-conditioning equipment was updated in 2024: Purchasing Energy-Efficient Residential Central Air Conditioners. Verify the directory and equipment requirements when comparing a purchase; certification does not replace correct sizing or installation.
Quick Recap
Rank #4
- Three-in-One Unit: Our 12,000 BTU (8,350 BTU SACC) air conditioner also functions as a dehumidifier & fan. This portable air conditioner has a full function remote control & top mounted control panel with LED display
- Portable AC: Take this personal air conditioner (16.5” x 14.06” x 27.09) in rooms up to 550 sq. ft. Stay cool in the hot summer months and sleep well with this BLACK+DECKER ac unit for bedroom
- Smart AC with Voice Control: This smart air conditioner allows Wi-Fi connectivity and can be controlled using our mobile app available on iOS and Google Play stores, and voice controlled by Amazon Alexa or Google Assistant
- Follow Me Remote: Our portable AC unit comes with a full function remote control that features a FOLLOW ME function, which allows the remote to act as a thermostat for precise temperature control
- Installation Kit: When it comes to fans that blow cold air, this indoor ac unit includes an easy-to-install window kit. A large, vented airflow outlet ushers in cool air
What to do if cooling fails during the heatwave
- Make only the thermostat, filter, and airflow checks above.
- Call a qualified HVAC technician for persistent warm air, electrical symptoms, leaks, or suspected refrigerant problems.
- Move people at risk into air conditioning rather than waiting in a dangerously hot room. Check on vulnerable household members, stay hydrated, and use local heat alerts to guide plans.
- If anyone becomes confused, faints, loses consciousness, or may have heatstroke, call emergency services immediately.
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