If you live in a sprawling, mature home that is fitted with an older air conditioning system, then you may not be too happy with its efficiency. You may feel perfectly fine in one corner of the house, but may be shivering in another while sweating in a third. It may be that the balance of your home is off, and you may need to take action in order to bring everything back in line. After all, you want to make sure that you are keeping your costs in check, and inefficiencies could lead to a larger bill, so what should you look at?
If it has been some time since the HVAC system was fitted into your home, then you need to work out whether it is large enough or is configured according to the latest and best research. Time moves on and so does technology, and engineers know a lot more about residential air conditioning today than they did "back then."
For example, you may need to add a second air handler. Older systems like this will only have a single one, which would be used for both heating and cooling, and which would typically be located on the bottom floor or even in the basement. It may be perfectly capable of pushing the warm air up (as this tends to rise naturally in any case) but it may struggle to push the cool air up into those same spaces. You may need to add a second air handler further up the building, but you may also need to have a look at the individual fan speeds and add a booster if needed.
You should also have a look at the ducting system to see how efficient it is. In particular, watch out for any kinks or leaks, and make sure that they are fixed before you do anything else. You may also need to add some other return ducts and grills to balance the system and make sure that the pressure is correctly maintained throughout the home.
Finally, make sure that your thermostat is not situated close to electronic items, as these tend to give off heat and could be affecting the set temperature.
Some of these tasks may be beyond the remit of the average homeowner, and if you find yourself in this position, you should bring in an experienced HVAC technician to advise you further.