Air Conditioner vs. Air Cooler: Which is better?

If you have ever attended an outdoor event in the afternoon in  Singapore, you already know the answer to why cooling matters. With temperatures regularly hitting 32°C to 34°C and humidity hovering around 80%-95% for much of the year, keeping guests comfortable is a necessity.

At Tentage Rental Singapore, two of the most commonly requested items for events are portable air conditioners and air coolers. On the surface, both does the same job: they cool people down. But the way they work, the conditions they are suited for, and what they require are quite different. Getting this decision wrong can mean your cooling solution underperforms on the day — leaving guests uncomfortable and your event experience falling short.

We hope to cover the key differences between the two and how you can choose the most appropriate device for your event.

1. Key Differences: How Each System Actually Works

Understanding the fundamental difference between the two systems is the starting point for any decision.

Air Conditioners (Portable Air Con Units)

A portable air conditioner works by removing heat and humidity from the air. It draws warm air in, passes it over a refrigerant-cooled coil, and expels cool, dry air back into the space. The heat extracted from the room is expelled via an exhaust hose or duct, typically through a gap in a wall, window, or tentage panel.

Because air conditioners actively dehumidify the air as they cool it, they are highly effective in Singapore’s humid climate. The result is a noticeably cooler and drier environment — the kind of smooth skin feeling when you walk into a hotel ballroom or a shopping centre. However, air conditioners can only work in a sealed environment. Using an aircon in open air is akin to opening the door in an aircon room. The volume of air increases and the aircon’s capacity is not enough to cool the additional space.

Key characteristics of air conditioners:

• Actively cools and dehumidifies the air
• Requires an exhaust outlet to expel hot air
• Most effective in enclosed or semi-enclosed spaces
• Higher power consumption

Air Coolers (Evaporative Coolers)

large air cooler at swab test site

An air cooler works on a completely different principle: evaporative cooling. It draws in warm air, passes it through water-soaked pads, and releases cooler air into the space. There is no refrigerant, no exhaust hose, and no compressor.

Air coolers work best in both indoor and outdoor situations. Being a tropical country where the humidity is already high, the air cooler does not make much difference in the humidity. In an open or semi-open space with cross-ventilation, they can provide a meaningful drop in wind temperature and make guests significantly more comfortable. Usually about 2-5 degrees Celsius.

Key characteristics of air coolers:

• Cools using water evaporation — adds slight moisture to the air
• No exhaust required — fully self-contained
• Most effective in open or well-ventilated spaces
• Lower power consumption
• Easy to position and reposition anywhere on site
• Requires a top up of water every few days

Quick Comparison at a Glance

2. Which Cooling System Suits Your Event?

The single most important factor in choosing between an air conditioner and an air cooler is whether your event space is enclosed, semi-enclosed, or open.

Fully Enclosed Spaces — Air Conditioner

If your event is taking place in a fully enclosed room or a fully sealed tentage — an air conditioner is almost always the better choice. In an enclosed space, the cool air stays contained, the unit can bring the temperature down effectively, and the dehumidification effect makes a real difference to comfort levels. That said, it is important to take note due to the increased electrical load. Usually a generator is needed to support air conditioners. If you are using a tent, you will also need to make a conscious effort to seal the tent. All these will add into the cost when compared to a Tentage using Air coolers instead. Usually resulting in 2X the price from using air coolers.

Examples: indoor seminars, VIP rooms, aircon tentage setups, product showroom launches, solemnisation ceremonies in enclosed tents.

Semi-Enclosed Spaces — Either, Depending on Configuration

Semi-enclosed spaces — such as tentages with open sides, void decks, covered walkways, or sheltered outdoor areas — can work with either system, but with important caveats.

Air conditioners can still be effective in semi-enclosed tentages if the openings are minimised and the unit’s capacity is sized generously. Air coolers are often more practical here because they do not require an exhaust, are easier to deploy, and perform reasonably well when there is some natural airflow passing through. As air coolers are not much different from Industrial fans, it is much cheaper to implement when compared to aircons

Examples: A-shaped or dome tentages with partial side panels, void deck events, covered carpark celebrations, outdoor wedding receptions under a tentage.

Fully Open Outdoor Spaces — Air Cooler

In a fully open outdoor setting with no enclosure, air conditioners are not viable — there is simply no way to contain the cooled air, and all the cooling effort is immediately lost to the open environment. Air coolers, however, are well-suited for this scenario. Positioned strategically around the perimeter of a seating area or at key high-traffic points, they create localised cooling that guests can benefit from while standing or sitting nearby.

Examples: outdoor funfairs, community events, pasar malams, school sports days, outdoor stages and concert areas.

3. Air Conditioning Requirements: What We Need From You

Portable air conditioners are not a plug-and-play solution that can be dropped anywhere. For us to properly size and configure an air conditioning setup for your event, there are a few things we will need from you upfront.

Photos and Measurements of the Space

Please provide photos, videos and the measurements of the area to be cooled — length, width, and ceiling height where applicable. This allows us to calculate the total volume of the space and determine how many units and what total BTU (British Thermal Units) capacity is required to achieve comfortable cooling. Without accurate dimensions, it is very difficult to give a reliable recommendation.

Also let us know whether the space is indoors or outdoors, and whether it is fully enclosed, has open sides, or has gaps. This context makes a significant difference to the sizing calculation.

Places That We Can Exhaust The Warm Air

As mentioned previously, air conditioners require an exhaust due to the heat exchange process. As such, your venue needs to have windows/doors/rooms that are not in use to direct the hot air to those areas. If you do not have any of this, Air Coolers might be the next suggested cooling equipment. As the hot air from the exhaust will simple negate the cool effects from the other end.

30000btu portable zircon with exhaust

Number of People in the Room

The number of guests is something most people overlook. Each person generates body heat — approximately 75 to 100 watts of heat output on average — and in a crowded space, this can raise the ambient temperature significantly. A room designed for 30 people will cool very differently from the same room packed with 150 guests.

As a rough guide:

• Up to 30 pax in a small enclosed space: 1 to 2 portable AC units typically sufficient
• 30 to 80 pax: 3 to 5 units depending on space size and insulation
• 80 to 150 pax: 6 or more units, or a combination with supplementary air coolers at entry points
• Above 150 pax: Best to discuss with our team for a tailored assessment

A general guideline is to always offer more than offer Less. If the room gets too cold, you can always switch off 1 or 2 air conditioners. But if you have less than sufficient. All your guest just end up being warm.

The more accurately you can estimate your guest count, the more precise our recommendation will be.

4. Power Usage: What to Expect From Each Option

Power consumption is a practical consideration that affects both your generator rental requirements and your overall event budget. Here is what you need to know for each system.

Air Conditioners — Higher Power Draw

Portable air conditioners are power-hungry by nature. A typical portable unit draws between 1,000W and 2,500W depending on its cooling capacity. If you are running multiple units simultaneously — which is often necessary for larger spaces — your total power load can quickly add up to 10kW or more.

For events without access to building power, this means you will need a generator with sufficient capacity to handle the AC load alongside other electrical equipment (lighting, PA system, projectors, etc.). Our team can help you calculate your total power requirements and recommend the appropriate generator size.

Important note: air conditioning units should ideally be on dedicated circuits to avoid tripping breakers. This is something we factor into our wiring planning.

Air Coolers — Lower Power Draw

Air coolers are far more energy-efficient. Most units draw between 100W and 300W — roughly equivalent to a few light bulbs. A bank of five to ten air coolers can often run comfortably off a single standard generator or a shared power circuit without significant concern.

This makes air coolers an attractive option for events in locations with limited power supply, or where you want to minimise fuel costs for generator runtime.

5. Cabling: Planning Your Electrical Layout

Both air conditioners and air coolers require careful thought around cabling and power distribution. Getting this right ensures your equipment runs safely and reliably throughout the event.

Cabling for Air Conditioners

Because portable AC units draw significant current, they require properly rated cabling and, in most cases, dedicated power circuits. Running multiple AC units off a single extension lead or shared socket is a fire risk and will almost certainly trip the breaker.

For events using portable air conditioners, our standard approach involves:

• Dedicated wiring runs: Each AC unit should ideally have its own circuit from the distribution board or generator output.
• Correct cable rating: Cables must be rated to handle the amperage draw of each unit — typically 13A to 16A per unit. 32A for Tentage air conditioners that are 5hp and above.
• Cable routing: Cables must be laid safely to avoid trip hazards, particularly in areas with high foot traffic. We use cable covers and secure routing as standard.
• Exhaust ducting: Each AC unit requires an exhaust hose to expel hot air. This needs to be routed through the tentage wall, a gap in a panel, or a purpose-made opening. Planning this in advance avoids last-minute complications on setup day.

Cabling for Air Coolers

Air coolers are considerably simpler to cable. Each unit runs off a standard 13-amp plug and socket, meaning they can share circuits with other general equipment without concern, provided the total load on each circuit remains within safe limits.

For larger deployments with many air coolers, we may still recommend a dedicated distribution board run to keep things tidy and safe, but the individual unit requirements are straightforward.

One additional consideration for air coolers: they require a water supply or regular topping up of their internal water tanks. For longer events, plan for a water source or scheduled refill intervals to keep the units running at full effectiveness.

Making the Right Call for Your Event

To summarise: if your event is in an enclosed or semi-enclosed space and comfort is a priority, a portable air conditioner will deliver the most effective cooling. If your event is outdoors, open-air, or in a space where running exhaust ducting and heavy cabling is impractical, air coolers are your best bet — efficient, flexible, and easy to deploy.

In many cases, the ideal solution is a combination of both: air conditioners for the main enclosed seating or dining area, and air coolers positioned at entry points, buffet areas, or open-sided sections of the tentage.

At Tentage Rental Singapore, we have been helping event organisers navigate exactly these decisions for over 15 years. Whether you need a single unit or a full cooling setup for a large-scale event, our team is happy to walk you through your options and put together a solution that fits your space, your headcount, and your budget.

Contact us with your event details — including photos, measurements, and expected guest count — and we will take it from there.