We have an almost square house. Toward the garage are 2 bedrooms, 1 bath and laundry room. They are probably 15 degrees colder when the A/C is on. Meanwhile, the master bed and bath and the kitchen and living room are very warm. Help, we have tried closing vents, (still cold) stuffing towels in the vents to partially block...nothing seems to work. The house is 10 yrs old.
Ruth D. ~ Houston, Texas
Hi Ruth. It's not unusual to have a problem with balancing the HVAC system in a home, but it is a little unusual to have it continue even if you have air flow to rooms completely closed off. I assume you have a single zone system which means your entire home is heated and cooled with one system and controlled with a single thermostat.
Some larger homes have two or more zones and each zone has its own system and thermostat -- a basement or upper level may be on a separate zone or even one portion of a single level home. In cases such as these it's important that you are adjusting the appropriate thermostat.
If you're sure you have a single zone system, take a look at your interior air handler or furnace where the main supply ducts exit the unit. These main supply ducts often have metal levers on the sides that allow you to adjust the air flow to certain parts of the home. The levers control dampers inside the ducts that adjust the air flow to sections of the home the ducts service. It's possible that the areas of your home that don't seem to be receiving enough air conditioning may have their main supply dampers almost all the way or completely closed. This would explain why some rooms are getting too much cooling when you turn on the air conditioning and others not enough. You may not notice it in the winter, but when the heat of a Texas summer arrives it can become very obvious. You can adjust those dampers to increase or decrease air flow as needed.
The best way to balance your HVAC system so that all rooms get adequate heating and cooling would be to have a professional contractor from around Houston visit your home. They can use a meter at each rooms' vents to determine how much air flow is entering the room and can figure out how much the rooms should be receiving based on their size. They also take into account the locations of windows and doors in each room as they can contribute to the cooling load needed for each area.
They may suggest installing dampers if your system doesn't already have them or they may feel that a second zone may be needed to supplement your original system. Having them come out and balance your system doesn't cost much and if they suggest modifications, you can make the decision as to when or if you wish to implement them. Once they balance your system it's important to leave dampers and vents adjusted as they left them as moving them can put you back where you started.