By Carl Seville, Networx
Plenty of people who run central air conditioning systems in Houston (and other cities where hot weather dominates the calendar) complain about how their air conditioning doesnít do a good job keeping their home comfortable, and, in most cases, they are probably right.† There are so many things that can and do go wrong with central HVAC systems that itís tough to know where to start, but Iíll give it a shot.
1. Leaky ducts
Probably the single biggest cause of poor AC performance is leaky ducts.† Ducts are kind of like pipes Ė they move air through them and deliver it at the end.† We notice when our water pipes leak because we see the damage immediately, but we rarely see the effects of leaky ducts directly; rather it sneaks up on us over a long period of time, and many people never figure it out.† When ducts leak, they let cool air out into whatever space they are in, often the attic, which, in case you havenít noticed, can get pretty hot in the summer.† Ducts need to be sealed at all the metal-to-metal and metal-to-flex connections Ė not at the insulation.† Have someone pull back all the insulation and put a nice thick layer of goopy mastic at all the joints, then replace the insulation.† Donít use duct tape. It wonít work, and the metal tape designed for ducts doesnít do a whole lot better.
2. Too much or too little refrigerant charge
Something else that can make your AC inefficient is the refrigerant charge.† Traditional AC uses a refrigerant that transfers the heat between the inside and the outside.† Every system is designed to work efficiently with a specific amount of refrigerant, and too often there is either too much or too little in the system.† A good HVAC contractor can check the charge and either add or remove some to make sure it is set correctly.† A wrong charge can decrease the efficiency by 20-30%, so checking and fixing this can make a big difference.