Learn About Portable Air Conditioners

There are two main types of portable air conditioner:

1. Coolzy – small, light, low power, provides micro-climate around people who need cooling. A Coolzy is a personal, localized air conditioner for cooling people, not rooms.

2. Old-style portable room air conditioner, large, heavy, high power consumption, with one or two large pipes that connect to a nearby window or pass through a doorway. These machines are designed to cool a room and come in two varieties:

  • Portables with one pipe: Unfortunately they suck out more air than they cool. They replace it with hot & humid outside air.  Nearly all of the electricity is wasted, and there is only slight room cooling.
  • Portables with two pipes: One pipe pulls in warm outside air, and the other pipe exhausts hot air to the outside. These machines are much more efficient than the single hose variety, but have only about half the efficiency of a mini-split room air conditioner. If the end of inlet pipe is close to the end of the outlet pipe, some of the hot air will be sucked into the inlet pipe.

Both single hose and dual hose portables are noisy. Noise can be reduced by making them heavier, so quieter models tend to weigh 60 – 75 lbs (30 – 35kg). Moving these machines can difficult!

Both single hose and dual hose portables radiate considerable heat from the hot exhaust hose. It is possible to insulate the hoses, but that makes them even larger and heavier.

Single hose portable room air conditioners consume as much power as the dual hose models but provide much less room cooling and comfort.

Dual hose machines are more awkward to set up, but provide around twice as much room cooling for the same electricity consumption and power rating.

Differences between Coolzy and old-style portable air-conditioners

Coolzy: 22 inches high x 11 inches wide x 15 inches long (55 cm high x 29 cm x 39 cm), 34 lbs (17.5 kg), easy to carry.

Old Style

Portable: typically 32 inches high x 16 inches wide x 18 inches long (80 cm high x 40 cm x 45 cm), 70 lbs, (32 kg), one or two 5 inch diameter pipes 6 feet long, Hard to move.

In moderately hot weather, a Coolzy can be used on its own (as shown) or with a normal mosquito net. We recommend the optional Igloo bed tent in really hot conditions with indoor temperatures consistently over 80 °F (27 °C) at night. The tent amplifies cooling over the bed and can also reduce energy consumption by about 30-40% which is ideal for battery and off-grid applications.

Old style portables are unsuitable for bedrooms. They are much noisier and have relatively low cooling performance compared with a split AC using the same power. Also humidity builds up in room with time.

Coolzy: use it anywhere because there is no pipe

Old-style Portable: has to be close to a window to attach the large exhaust pipe with the window kit

Electricity is the largest part of the cost for any room air conditioner.

Coolzy: Total cost over 5 years is about $750 of which electricity cost is about $300

Old-style Portable: Total cost over 5 years is about $1,400 of which $1100 is the electricity cost.

Calculations are based on average USA electricity cost 15 cents/kWh, 8 hours a day running, 5 months. Electricity cost in some cities can be 30 cents/kWh.  While solar panels can provide free daytime electricity, the cost of battery storage for night time air conditioner use is currently about 25 cents/kWh.

Coolzy: 800-1,100 Watts cooling, 340 Watts electricity (same as a handful of lights), 0.3 tonnes CO2 over three years, equivalent to 30 gallons (120 litres) of petrol

Old-style Portable: 3,000-7,500 Watts cooling, 1,000-2,400 Watts electricity, 1-2 tonnes CO2 over three years, equivalent to 110 – 220 gallons (450-900) litres of petrol.

Coolzy: all cooling directed around people using it, does not cool room

Old-style Portable (single pipe): mixes air in room, sucks out more air than it cools and sucks in hot air from the roof space outside. Very little room cooling.

Old-style Portable (dual pipe): mixes air in room, about twice room cooling for same power consumption as single pipe, significantly less cooling than a mini-split with same power consumption.

Coolzy: 47-54 dB – quiet, like an electric fan

Old-style Portable: 55-63 dB – noisy, can be hard to hear people speak

Coolzy: Open windows and doors allow fresh air to circulate, indoor air quality similar to fresh air outside.

Old-style Portable (single pipe): Windows closed, however outside air is sucked in because of single exhaust pipe so indoor air quality is similar to fresh air outside.

Old-style Portable (dual pipe): Normally there is no provision to provide fresh air to the room, so indoor air is not refreshed. CO2 and other pollutants accumulate over time. 

A Coolzy eliminates the need for an exhaust hose: such a wonderful improvement. It is on caster wheels and can easily be moved where you want to use it. At only 34 lbs (15.6 kg) it is easily carried too. Take it anywhere you need cooling, even outside in sheltered places.

The old-style portable comes with a hose and window kit which is fiddly to install, and only works with some windows. The machine typically weighs around 70 lbs (32 kg). That means you cannot easily move it once you have installed it. Plus the exhaust hose is ugly, helps to heat the room, and makes lots of noise.

Answer: A Coolzy releases only 340 Watts, similar to three people in the room. A Coolzy directs its warm air exhaust to the ceiling where the heat is absorbed, just like the warmth from your fridge which you don’t notice (warm air rises naturally). Any excess finds its way out of open windows or doors.

Without sufficient ventilation, even this small amount of heating can raise the temperature in the upper part of a small room. Learn how to provide extra ventilation for a small room.

A Coolzy works in any room, even outside in sheltered places. It creates a micro-climate, a cool zone, up to 6 feet by 6 feet (about 36 sqft).

If the temperature inside your bedroom regularly exceeds 80 °F (27 °C) at night, the Igloo bed tent provides extra cooling to keep you comfortable, and also provides chemical-free mosquito protection.The Igloo bed tentalso reduces the air conditioner power consumption to about 180 Watts average, a valuable saving for off-grid battery installations.

The Igloo bed tent also provides an ideal place for your baby or small child to be cool and comfortable during the day time.

We recommend keeping a Coolzy near you, no more than 3 to 6 feet away (1 or 2 metres).  If you need it further away, or want to use while you are standing, we recommend our Focus Enhancer accessory which extends the range and optionally directs the cool air flow at a higher angle.

If you need to cool a crowded room for 2 – 3 hours, a split AC is effective. Split ACs provide no fresh air exchange and the doors and windows need to be closed to retain the cool air so carbon dioxide, volatile organic compounds and body odours build up with time. Prolonged use of split ACs for sleeping can cause dry itchy eyes and skin irritation from dry air and the running cost can be very high. Expect to pay $1,500 or more to install it and $45 – $100 a month for electricity if you use it for sleeping or during the day. 

You can use your Coolzy with the split AC at the same time, leaving the split AC thermostat at a higher temperature to save on running cost. Coolzy provides extra cooling where you need it.


Drink lots of water in hot weather.

Ceiling fans can be effective in moderate heat.

An electric fan on a table next to a window can draw outside air through the open window and blow it across a bed to provide effective cooling for sleeping. Make sure that there is one other open window or doorway tor air to escape.

Fans provide about 3.5 degrees of apparent cooling (2 degrees Celsius). (A Coolzy provides up to 18 degrees of apparent cooling, sometimes more (10 degrees Celsius).)

A large roof exhaust fan installed in ceiling of the highest room in the building can provide cost-effective cooling at night for the entire building, especially for brick buildings. The air flow capacity should be about 2,000 – 3,000 cubic feet per minute with a low speed motor drive to ensure quiet running. Arrange for the fan to be switched on around 10 pm, and let it run until about 7 am. Leave some windows open to ensure that fresh air can be drawn into the building and pass through other rooms before reaching the exhaust fan.

Roof exhaust fans prevent a building from getting hotter every day of a heat-wave: the building cools to a temperature 4°F above the night time minimum temperature. A Coolzy can work well with a roof ventilation fan to provide extra cooling when needed.

In dry weather (up to about 60% relative humidity), evaporative (water) coolers can provide effective cooling.  There are many types available, both mobile (not portable) and ducted systems.  Avoid small portable models as they require frequent refilling with water, or have limited effectiveness.  Indirect evaporative coolers provide cooling with only moderate increases in humidity.  Direct evaporative coolers, the more common type, do increase humidity and can cause very high humidity at night. A Coolzy can work well with ducted evaporative cooling systems for homes and offices.

In extremely hot conditions, wet towels draped on your legs can provide effective cooling and sun protection when travelling by car.

Coolzy.com is a Australia based start-up company founded in 2007. The company now sells in 32 countries worldwide. Inventor James Trevelyan created the concept after experiencing summer heat in Pakistan with intermittent electricity for air conditioning.  He refined the concept with a series of prototypes, assisted by our manufacturers in Taiwan.  Our first commercial models went on sale in India and Pakistan in 2016.