Portable AC Without a Hose: What You’re Really Buying

An air conditioner doesn’t produce cold. It moves heat from the room to the outside, so it must have an outlet to the outside: a hose, on a portable AC, or an outdoor unit, on a wall-mounted AC.

Here’s how it works: the refrigerant absorbs heat from the room’s air, and the compressor compresses it and releases the heat on the other side, at the condenser. In a wall unit, the condenser is in the outdoor unit. In a portable AC, the condenser is inside the device, and its hot air goes out through the hose. That’s why, per an article on ynet (a major Israeli news site), a portable AC can’t work without an opening for the hot air to escape.

What happens if you run a portable AC without connecting the hose? All the heat it draws from the room returns to the room, plus the heat the compressor and fan generate from electricity stays in the room. The result is a warmer room, not a cooler one. It’s the same principle that explains why a fridge with its door open doesn’t cool the kitchen.

So when someone sells you a “portable AC without a hose”, check the product page: is there a cooling figure in BTU? Is a refrigerant like R32 or R290 mentioned? If not, and the page says water tank, ice packs or “cooler”, it’s an evaporative air cooler.

A cooler passes air through a wet filter. The water evaporates, and the evaporation lowers the air temperature. How many degrees does it drop? That depends almost entirely on humidity.

The physical principle, per the English Wikipedia summary on evaporative coolers:

• Dry air: in an example from Las Vegas, at 42°C (108°F) and dry desert air, a good home cooler brings the air coming out of it down to about ⁦22–23⁩°C (⁦72–73⁩°F).
• Humid air: in an example from Tokyo, at 30°C (86°F) and 85% humidity, the cooler can only bring the air down to about 28°C (82°F), an almost meaningless drop.
• Ventilation: the cooler needs fresh air all the time. In a closed room, humidity rises and the cooling disappears. That’s why you run it with a window open.

What this means in Israel: in the Arava, Eilat and the Negev, on dry days, a large cooler can genuinely help, especially on a balcony, in a workshop or in an open space. On the coast, from Tel Aviv to Haifa, summer is humid, and the cooler will mainly give the feeling of a humid breeze. In Jerusalem and hilly areas it’s in between: on dry afternoons it helps a little, and on humid evenings less.

In any case, the cooler mainly affects whoever sits in front of the airflow, not the whole room.

Ice packs add a little cooling for a short time. The amount of cold in them is very small compared with an air conditioner, so they don’t turn a cooler into an AC.

A simple calculation: melting a kilogram of ice takes about 334 kilojoules, which is about ⁦320 BTU⁩ in total. A 1 HP AC (Israeli stores size ACs in “horsepower”, where 1 HP ≈ ⁦9,000 BTU⁩/h) removes about ⁦9,000 BTU⁩ from the room every hour. In other words, a kilo of ice is worth less than 4% of what a small AC does in one hour, and it runs out after a short time.

In addition, while freezing, the freezer releases into the kitchen the heat it removed from the ice packs, so in the home’s overall balance there’s no gain.

When are ice packs noticeable? When you sit right next to the device, in the first few minutes after putting them in. The Eco Euro ECFC-120 page states that 2 freezer containers are included in the box, and the Gold Line ATL-486 page mentions a slot for swapping ice packs. That’s useful for a desk, not for a room.

A cooler is cheap and uses little electricity, but it lowers the temperature only in dry air and only for whoever’s in front of it. A portable AC with a hose costs more and uses more, but it cools the whole room even on the coast.

Per the product pages we checked:

• Electricity use: the Gold Line ATL-486 cooler uses 60 watts, the Midea AC200-W 100 watts and the Venta Cyclone 12000 250 watts. A ⁦9,000 BTU⁩ portable AC uses several times that. For example, a 1 HP wall unit like the Electra Relax Inverter 140 draws about 850 watts at full cooling per the specs.
• Price: a cooler costs about ₪⁦140–1,500.⁩ A real portable AC costs about ₪⁦900–2,100,⁩ per our portable AC guide.
• Installation: a cooler needs no installation. A portable AC needs a window or opening for the hose, and sometimes a window sealing kit.
• Humidity: a cooler adds humidity. An AC removes humidity. In a damp home prone to mold, that’s an important difference.
• Water: you fill a cooler with water. With a portable AC you sometimes need to empty a condensate tank, and per Tornado high humidity increases the amount of condensation.

Bottom line: anyone who wants to cool a bedroom in Tel Aviv in August needs an AC, portable or wall-mounted. Anyone who wants a cool breeze at their desk in Mitzpe Ramon can make do with a cooler.

A cooler works best when the air going into it is dry and has somewhere to escape. Used correctly it gives a cool breeze; used incorrectly it just adds humidity to the room.

Practical tips:

• An open window: per the Wikipedia summary, a cooler needs many air changes per hour to work. In a closed room, humidity rises and the cooling disappears.
• Placement: put the cooler near the window, with the airflow aimed at you. That way you get the dry outside air, cooled.
• Cold water: cold tap water, or ice packs in the first hour, add a bit of cooling. Evaporation does most of the work.
• Time of day: at midday, when the air is drier, the cooler works better than on a humid evening.
• Cleaning: empty the tank when the device isn’t in use, dry it and clean the sponge filter. Standing water grows mold and odors.
• Watch the humidity at home: if mold or damp appears on the walls, stop using the cooler in that room.

In winter, many coolers also work as a regular fan. They don’t heat. If you also need heating, a portable or wall-mounted AC with a heat pump is the solution.

In most cases there’s a solution that genuinely cools: a portable AC with a hose through a window, or a wall unit with a special installation. A cooler and a fan are an add-on, not a replacement.

The options by situation:

• Renters whose landlord won’t allow drilling: a portable AC with a hose going out through a sliding window, with a sealing kit. No drilling needed, and you can take it with you when you leave. Recommendations and models are in our portable AC guide.
• No room for an outdoor unit: sometimes it can be installed on the roof, in the laundry niche or on a bracket. Long piping makes installation more expensive: per pro.co.il (an Israeli contractors’ site) about ₪⁦120–150⁩ per extra meter. Details are in our AC installation cost guide.
• A room without a window: a portable AC won’t work without an outlet, and a cooler won’t work without ventilation. Here you need a wall unit or mini-central with piping from elsewhere.
• You only want the feel of a breeze: a ceiling fan uses tens of watts, moves air around the whole room and doesn’t add humidity. The comparison is in our ceiling fan guide.

If you bought a cooler anyway, use it correctly: cold tap water, an open window, sitting in front of the airflow. Empty and dry the tank when you’re not using it, to prevent odors and mold.