If you are having cold and hot spots in your house, try the following measures to see if they can help.
Open and Close the Vents as Necessary
You can try opening up all the vents so that you can get a true picture of the cold and hot spots in the house. Leave all the vents open for at least a day for the AC temperature to reach and affect all the areas of the house. After that, you can adjust the vents to increase airflow in areas that are warmer than the rest of the house. You may have to do this several times until the desired temperature is reached.
Ensure All the Registers Are Clean
In some cases, you may be experiencing hot and cold spots because the AC filters are dirty. As you know, the filters clean the air entering the AC system, but they also get dirty with the debris they trap. When the filters get too dirty, they reduce air flowing through them, and reduced airflow means reduced cooling. In such a case, the interior rooms may remain cooler than the outer rooms.
Reduce Heat Energy From Outside
Apart from dirty filters, heat from outside the house may also cause some rooms (particularly the outer rooms) to feel warmer than others. This may be the case, for example, if the windows don't have coverings and sunlight is streaming directly into the house. It may also be the case if you have an open skylight that is admitting heat into the house. Reducing these sources of external heal will help ensure uniform heating.
Prevent Airflow Restrictions
An efficient AC system doesn't just cool the air it receives; it also ensures the air is circulated throughout the house. Unfortunately, you can interfere with air circulation if you are blocking the vents that are supposed to supply the rooms with air. For example, if a large piece of furniture (say a bookcase) is blocking a vent, the area that the vent is supposed to supply with cool air will feel warmer than the other areas.
Ensure the Ductwork is Intact
Lastly, damaged air ducts that are leaking air may also interfere with your air-balancing acts. Vents can be damaged by animals, accidents, or wear and tear, but the result for each case will be the loss of cool air. That means the areas that the affected vents are supposed to supply with cool air will feel colder than other areas whose vents are intact. It also means that fixing the damaged vents will reduce the incident of hot and cold spots.
Hopefully, the above tips will eliminate hot and cold spots in your home. Consult an HVAC technician like Northwest Heating & Air Conditioning Inc if the above tips don't help.