Dehumidification

A large part of how cool you feel in an air conditioned space during summer is how much humidity has been taken out of the air.

If there is moisture in the air of a room, the room may feel cooler than outside, but it can feel damp or claustrophobic. This is part of the reason that swamp coolers do better in different areas of the country. Newer air conditioning units allow more humidification during the summer to ensure that your home stays comfortable and cool, without making the air feel too "heavy."

If there is a respiratory problem in the home, additional specialty units can be used in conjunction with the original home heating and cooling system. These include, air cleaners, humidifiers and even ventilators. These specialty units allow for a higher circulation of air, even in a tightly sealed home.
Likewise, homeowners in some areas of the country (with high humidity) might consider an additional add on to their unit. A dehumidifying heat pipe is a fairly new development that will take humidity out of the air, before it enters the cooling phase, making your home considerably cooler during the hot summer.

Source: US Department of Energy, Energy Efficiency and Renewable Energy "Energy Savers" page, regarding the home. http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12740

A dehumidifying heat pipe resembles two heat exchangers, located on either side of the air conditioner's evaporator coil. Several tubes connect the two sections. A refrigerant (usually an HCFC) inside the tubes pre-cools the incoming supply air by absorbing the heat from it. This causes the refrigerant in the tube to evaporate. The air conditioner evaporator cools it further, extracting up to 91% more water vapor than a conventional evaporator would. After the refrigerant in the tubes changes into a vapor, it flows to the condensing section at the other end of the system. There, it releases its heat into the air stream and returns to its liquid state again. Gravity then causes the refrigerant to flow to the evaporator end of the pipe to begin the cycle again.

Most models of heat pumps and central air conditioners can be retrofitted with dehumidifying heat pipes. You can choose either a replacement cooling coil that incorporates the heat pipe, or add-on heat pipes for the unit's ventilation system. You may also want to consider a complete air-conditioner unit that incorporates the heat pipe.

Although the heat pipes don't use any electricity directly, they cause the conditioned air to leave the system slightly warmer than it would have in the absence of the heat pipe, so it takes more energy to cool your home. The system also consumes more fan power to blow air past the heat pipe. However, the manufacturer claims that your thermostat can be set higher with the low humidity air, allowing a net energy savings.

If humidity is an issue in your home, there are several different things you can try to resolve the problem. Using extra fans to push air around the rooms will help to alleviate some of the humidity. Running them in conjunction wiht an air conditioner may also be helpful. Avoid cooking or hot showers that may add to the amount of moisture in your home during peak heat hours. Finally, consider upgrading your air conditioning unit and possibly adding on a humidifying or ventilating option. If that still fails, a dehumidifying heat pipe may be the answer. Although in Southern California, this issue shouldn't be that difficult to fix.