Normally our first thought for home cooling will be air conditioning, but there are many alternatives that provide home cooling while using less or no energy. With a combination of proper insulation, energy-efficient windows and doors, shading, and ventilation you will usually be able to keep a home cool with a low energy usage.
Even though ventilation should be avoided in very hot and humid climates, there are other cheap cooling methods that can significantly reduce the need to use an expensive air conditioning system.
Home Ventilation Systems
Home ventilation is the cheapest and most energy-efficient method to cool a home or building. Ventilation works best when combined with other methods that avoid heat buildup in your room, home or building. Sometimes natural ventilation will be all you need to cool your home, but it usually needs to be supplemented with ceiling fans, window fans or spot ventilation.
An exhaust fan inside the kitchen and bathroom are standard equipment in all the newly built houses. Exhaust fans are often used to provide simple spot ventilation for expelling moisture and odors from kitchens and other rooms.
Controlled home ventilation systems operate many hours per day. You want to install a durable, high-quality fan intended for continuous use . Most high-quality ventilation fans use permanent split capacitor motors. Because this fan will run thousands of hours a year, be sure to look for a fan motor with a low electrical consumption.
In hot, humid climates where the temperature difference between day and night is small the use of ventilation will be ineffective. In these sorts of climates, an attic ventilation system can help to reduce the usage of the air conditioner. Ventilating your attic will greatly reduce the accumulated heat, that could eventually works its way into lower parts of your home. Ventilated attics are about 30°F cooler than unventilated attics.
For large homes, homeowners might want to investigate whole house fans.
Ceiling Fans and Other Circulating Fans
Circulating fans like ceiling fans, table fans or mounted fans create a wind chill effect that will make you feel more comfortable in your home, even when your home is also cooled by natural ventilation and/or an air conditioning system. Ceiling fans are considered the most effective of these types of fans, since they effectively circulate the air in a room to create a draft throughout the room.
If you use air conditioning, a ceiling fan will allow you to raise the thermostat setting by about 4°F with no reduction in comfort.
Radiant Cooling Systems
Radiant cooling systems work by absorbing the heat radiated from the rest of the room keeping the floor or the ceiling cool. When the floor is cooled, this is often referred to as radiant floor cooling; cooling the ceilings is mostly done inside houses that have radiant panels installed.
The key to cooling a home with radiant cooling is to first control the moisture in the air (lean) through dehumidification and then control the surface temperature of the floor (dew point) Although radiant cooling is suitable for arid climates, radiant cooling systems can be problematic for homes in more humid climates.
Homes built on concrete slabs are prime candidates for radiant heating systems, and radiant floor cooling takes advantage of the same principle using chilled water. This is particularly economic in homes with existing radiant floor systems.
Evaporation Cooling Systems
In areas with low-humidity, evaporating water into the air provides an energy-efficient way of cooling. Evaporation coolers, also called swamp coolers, rely on this principle, cooling outdoor air by passing it over water-saturated pads, causing the water to evaporate into the air. The 15°–40°F-cooler air is then redirected into the home, pushing the warmer air out through the windows.
When operating an evaporation cooler, windows are opened part way to allow warm indoor air to escape as it is replaced by the evaporation cooled air. Unlike central air conditioning systems that recirculate the same air, evaporation coolers provide a steady stream of fresh air into the house.
evaporation cooling systems cost about half as much as regular air conditioners and they use about a quarter of the energy. They do however, require more frequent maintenance than regular air conditioners and they are only suitable in areas with low humidity.
Absorption Cooling Systems
Absorption cooling works essentially in the same way as regular air conditioners, the big difference is that they are driven not by electricity, but by a heat source such as natural gas, propane, solar-heated water, or geothermal-heated water. Because natural gas is the most common heat source for absorption cooling, it is also referred to as gas-fired cooling. Although mainly used in industrial or commercial settings, absorption coolers are now commercially available for large residential homes.
Absorption cooling usually only makes sense in homes without an electricity source, but may also be employed to make use of renewable energy. Absorption cooling is essentially a heat pump technology; absorption coolers are absorption heat pumps that are not set up to allow their use as a heating device.