Here in Florida our highest energy cost is air conditioning our homes. Central air conditioning systems are highly complex with many various parts. In most situations you have the unit outside the home which is the compressor and cooling fan. Somewhere inside the home, often in the garage or attic is the second part referred to as the air handler. Within this unit is an inverted V shaped piping system known as the cooling coils. There also is a fan and blower motor inside this unit.
Your air conditioning system is designed to move air at approximately 400 cubic feet a minute. There are some natural restrictions (static pressure) to the air flow designed into the system and accounted for in the design. Some of those restrictions are bends in the ducts, a filter, the louvers on your supply and return vents and the cooling coil. The system is designed to move the cooled air out through the ductwork into each space and then smoothly pull the warmer air back into the system through the return(s) to be cooled again and sent back out in a big loop. This process continues as long as your system is operating.
In Florida returns should be either in the ceiling or high up on the wall. I’ve seen many returns at the floor, which makes me think someone from a heating climate up north moved south and didn’t realize the difference between a heating and cooling climate. When your return is at the floor, you are pulling your coolest air out of the living space and leaving your warmest air at the ceiling.
Increasing restrictions to the circulation of your system will increase your cost by making the blower fan work harder. Here are three things people do not knowing they are hindering their system from operating at peak efficiency thus raising the cost of operation.
1) Installing a filter rated higher than MERV 8. The hypo allergy filters often are restrictive and block air flow, causing your blower motor to work too hard.
2) Closing supply vents in unused rooms. Picture your system working best when the air flows with the least restriction. When you close off rooms it is like trying to blow up a balloon that is already full. It causes too much pressure in the ducts putting a back pressure on the blower motor and making it work harder.
3) Closing bedroom doors when there is no return duct or balancing duct. Most Florida homes built before 2007 will have a main return in a common area and often a return in the master bedroom but that is it. Closing bedroom doors with no way to return the air except what can leak under the door has the same effect as closing vents. The easiest remedy for this is to put in a “jumper duct.” This is simply a piece of duct and a return vent on each end. It isn’t tied into the AC system. It simply connects the bedroom and the common living space. It acts as a pressure relief and allows air to get back to the main return.
What you should know before you purchase a new AC unit, click here!
Closing bedroom doors when there is no return duct or balancing duct. Most Florida homes built before 2007 will have a main return in a common area and often a return in the master bedroom but that is it. Closing bedroom doors with no way to return the air except what can leak under the door has the same effect as closing vents. The easiest remedy for this is to put in a “jumper duct.” This is simply a piece of duct and a return vent on each end. It isn’t tied into the AC system. It simply connects the bedroom and the common living space. It acts as a pressure relief and allows air to get back to the main return.
For any questions on your air conditioning system or any other energy related questions contact your energy experts at www.fpuc.com/energyexpert
