Some homeowners try to reduce their air conditioning expenses by closing the air vents in the parts of the house that aren't being used regularly, such as the guest rooms. However, such a habit may actually cause you to incur higher HVAC costs. This article discusses some of the reasons why your air conditioning costs may actually go up in case you close the air vents in the rooms that aren't currently occupied.

More Air Leaks Out

Some homes have leaks in the AC ducts due to several factors, such as poorly connected ducts and normal component wear. Small amounts of conditioned air usually escape from the HVAC system through those leaks. However, the quantity of air that leaks out can increase significantly in case you block or close some of the air vents in unused rooms. This is because the AC system was designed to condition the air in your entire house. Thus, shutting some vents means that more pressure will be exerted within the remaining ducts and vents. This higher pressure forces more air out of the holes and leaks. The result is that your system will work harder to keep your home within the set temperature range. That added work will result in the consumption of more energy.

Shorter Cycle Times

Shutting some air vents can also causes the air conditioning system to cycle on and off at shorter intervals than it was initially designed to. This is because the shut vents reduce the living spaces that are supposed to be conditioned by your system. In effect, your AC system becomes oversized for the reduced space that it is now conditioning. That is why it will cycle on and off at shorter intervals. These short cycle times will increase the rate at which system components, such as the compressor, wear out due to metal fatigue. You are therefore likely to see your AC repair bills increasing over time.

Poor Dehumidification

The short cycle times are also likely to have an adverse effect on your level of comfort. This is because the air conditioner will be unable to re-circulate the air through the system adequately in order to keep humidity levels within acceptable levels. You are therefore likely to adjust the thermostat settings upwards in a vain attempt to coax the system to remove more moisture from the air in your home. Those higher settings will make the system consume more energy.

As you can see, shutting some air vents in unoccupied rooms in your home is likely to increase your ducted air conditioning costs instead of reducing them. It is therefore better for you to talk to an HVAC expert for a lasting solution, such as upgrading to a split system AC, so that you can control the air conditioning within different rooms without affecting the overall efficiency of your installation.