Evaporative air coolers (also known as swamp coolers) use the natural process of evaporation to cool the air in your home. This works well in arid areas, where water evaporates quickly to lower the temperature of the air.
However, evaporative cooling also increases humidity levels, which could lead to mold or mildew problems in some homes.
How do they work?
Evaporative cooling relies on the natural process of water evaporation to lower air temperature. It’s the same basic principle that misting a person’s face on a hot day can help to cool them down. The machine takes this process and automates it to lower air temperature throughout the home or office.
A fan blows dry hot air across the cooler pads, which soak up water from a reservoir, and as the water evaporates, the air cools. It’s important to keep in mind that evaporative cooling only works well in hot and dry climates. It won’t work as well in wet climates like Melbourne, Adelaide, and Perth. For these regions, it is better to choose an air conditioner instead.
The cool vaporized water is then pumped into the home’s air through vents or ducting to distribute the fresh cool air. The system can be used as a standalone unit in small to medium homes or connected to a ducted cooling and heating system for large houses or office blocks. Evaporative systems use a high level of ventilation and must be placed in a position where the cooling air can easily flow to occupied rooms. A good position would be a spot on the roof or an area of the wall that can be opened to the outside.
It’s also important to remember that evaporative cooling uses no refrigerants, so the system is environmentally friendly. It does, however, require regular cleaning and maintenance. A quality evaporative system will drain all excess water and will never leave standing water, which can become a breeding ground for bacteria.
As well as being environmentally friendly, evaporative cooling provides occupants with clean, fresh, and balanced air. This improves indoor air quality and assists with the elimination of pollutants, odors, and viruses.
As an alternative to traditional air conditioning, a fixed evaporative system can save companies or offices thousands of dollars in running costs while improving employee productivity and health. Unlike compressor air conditioning that recirculates stale air, an evaporative system constantly replaces the stale indoor air with a steady stream of outdoor fresh air. This constant supply of fresh air prevents the buildup of harmful airborne contaminants and contributes to improved workplace concentration, safety, and overall performance.
How much do they cost?
Evaporative coolers cost less to buy and install than ducted air conditioning and cost a fraction as much to run. Typically, they cost $1 to $2 per day to run, compared to $5 to $10 for an air conditioner. They are particularly economical in drier climates, as the cooling system does not add any water.
The best evaporative cooler brands offer high-quality, durable designs. They also use advanced technology to maximize efficiency, reduce noise levels, and minimize the amount of maintenance needed. If you want a quality swamp cooler, you should expect to pay around $3,000 for a ductless mini-split or about $5,000 for a ducted evaporative cooler.
A basic evaporative cooler has a fan and a pump that draws in warm air, which passes over water-soaked pads. As the pads evaporate, the air cools and humidifies. The fan pushes the cool air through vents in the ceiling or through a series of ducts that deliver it to each room. Ducted evaporative coolers are suitable for larger houses and are ideal for zones with hallways and multiple rooms.
Most evaporative coolers require some regular maintenance. The pads must be replaced on a regular basis, and the water in the unit must be drained and winterized before it freezes. In areas with hard water, the evaporative media must be replaced every few months, or it may only last for a few years before mineral scale build-up unacceptably degrades performance.
To get the best evaporative cooling, you should leave your windows open to allow fresh air in and release moist air. This is necessary to ensure that the evaporative cooling system can cycle fresh air through your house on a constant basis. When you close your windows, you should be able to feel the cooling effect diminish.
It’s important to choose the right-sized evaporative cooler for your house. A swamp cooler that is too small will not cool your home properly, while one that is too large will waste energy. To determine the correct size for your house, a professional will measure your home’s square footage and calculate the CFM of each room. They will consider factors such as ceiling height, sun exposure, and room occupancy.
How long do they last?
Evaporative cooling is a simple system that turns water into cool vapor. The method is ancient – bronze-age frescoes show slaves fanning jars of water to keep cool. Evaporative coolers work best in arid climates where the air is dry enough for the water molecules to easily separate and float away. They do not cool the air as well in humid climates because the water vapor will add humidity to the room.
Evaporative coolers do not need complex electronics to function and cost much less than air conditioning systems to buy and install. They also use a fraction of the electricity of air conditioners. However, they will need some regular maintenance to ensure the evaporator coils are clean and functioning properly.
The evaporative cooler needs to drain any excess water on a regular basis to prevent the accumulation of bacteria. If the evaporative cooler does not drain properly, it could lead to a build-up of mineral scale, which can degrade the efficiency of the unit. The evaporative cooling system will also need to be drained and winterized before freezing temperatures arrive to protect the system from damage.
If a ducted evaporative cooling system is installed, it will require access to the roof for its exhaust pipes. It will also need to be connected to a freshwater supply and to an electrical circuit, so it is essential that these are properly maintained. Installing a portable evaporative cooler will be easier to set up because it only requires an outlet for the exhaust pipe.
A quality evaporative air conditioner will have the capacity to lower the wet bulb temperature of the air. The wet bulb temperature is the average air temperature minus the air’s moisture content, and it can be calculated from standard weather reports by using a psychrometric chart.
Evaporative cooling lowers the air temperature by passing it over damp filter pads, which causes the water to evaporate and cool the air. However, the cooling process also increases indoor humidity levels significantly, which can cause problems in some circumstances. High humidity can reduce the ability of a person’s skin, eyes, and nose to wick moisture away from the body, which can lead to discomfort and other health issues. In addition, high humidity accelerates corrosion in some environments and can disperse dust, odors, and other outdoor contaminants into the interior of a building.
How easy are they to install?
Evaporative air conditioners can be installed in a number of different ways. Some are hung on the wall of a room (in ducted cooling systems) or outside the building, while others can be mounted on the roof or in the window. Typically, the evaporative cooler is comprised of an enclosed metal or plastic box with vented sides and a fan that moves ambient air through the damp pads to cool the space. Some units have a built-in water pump to streamline the absorption of water into the pad.
The best evaporative cooling pads are made from natural fiber with a large, absorbent surface area. These are usually called Aspen or Honeycomb pads, and they can be bought from your local cooling specialist or at most home centers. They need to be replaced on a regular basis as the pads are exposed to salt, which damages the fibers over time. Alternatively, a synthetic pad is also available and has the advantage of resisting salt damage for much longer.
Evaporative cooling is best suited to dry climates. The temperature of the air is lowered as the water evaporates, while the humidity level stays the same. This is similar to how a cold cloth on your forehead feels good on a hot day — the moisture in your skin helps lower your temperature as the sweat evaporates.
An evaporative cooling system can be used in conjunction with an existing air conditioning unit to reduce energy costs. However, installing the evaporative cooler correctly is essential to ensure optimal performance. It is vital to have the right size pad for the room and for the evaporative cooler to be well positioned to take advantage of the outdoor breeze, as well as having a suitable exhaust point to release the cooled air.
Cooling performance is dependent on the dewpoint and relative humidity levels of the air, as measured with a psychrometric chart or simple computer program. This data is not normally available in standard weather reports, and therefore a special tool must be used to calculate the wet bulb and dry bulb temperatures of the air in order to determine the cooling capacity of an evaporative cooler.