September 23rd, 2014

Correcting Temperatures Differences Between Rooms

Home Owners Network

A common complaint about heating and cooling systems is wide temperature differences between rooms and between stories in homes. Heating and air conditioning (HVAC) contractors refer to correcting these temperature differences as balancing the system. An HVAC system that is properly sized and properly installed should require little, if any, balancing to achieve uniform temperatures between rooms. In practice, HVAC system sizing and installation errors are common and can make balancing difficult.


Your HVAC system should maintain a comfortable temperature in every room. Reasonable temperature expectations are 68˚ F during the winter and 78˚ F. or 15˚ F. below an outside air temperature of 95˚ F in the summer.

You should measure temperature near the center of the room and about five feet above the floor. The temperature you set at the thermostat should be about the same in every room served by the thermostat. A small variance (1 or 2 degrees) is considered acceptable.

Balancing temperatures between rooms is affected by numerous factors that can change based on the time of day and the season of the year. Some factors that affect balancing include: room location (south and west facing rooms can be more difficult to cool), size, quality and location of windows and doors, room size and ceiling height, size and location of supply and return registers, thermostat location, and location of the air handler relative to the room (the air handler must push air further through ducts in unconditioned space).

Because a balancing problem can have multiple causes, solving the problem can require multiple solutions.  Here are some simple potential solutions for balancing problems.

Confirm that all supply and return registers are open and unobstructed. Don’t, for example, close supply registers in unused rooms. This can cause air flow disruptions in the ducts that cause balancing problems.

Confirm that filters have been cleaned or changed per manufacturer’s instructions. Clean filters mean you’re getting maximum air flow from the HVAC system.

Confirm that ducts are sized and installed according to recommended standards. An HVAC contractor will need to do this. Design and installation errors, and damaged and leaky ducts, are common causes of balancing problems.

Confirm that insulation is installed properly and in the required amount. Insulation and air sealing can reduce drafts and discomfort.

Install sun screens on south and west facing windows in high heat areas. Sun screens can help in the sunbelt states on lots with minimal tree cover. Closing blinds in the summer and opening them in the winter helps too.

Plant deciduous trees on the south and west sides of your home (sun in winter, shade in summer).

Improve air flow in rooms with doors by providing a return air path if none exists.  Jumper (transfer) ducts are a good way to do this. These ducts jump, usually in the attic, between the room and a central hallway to provide the return air path.

If these solutions do not produce satisfactory results, other solutions may be required. These solutions may include changing the supply and return duct configuration and adding zones that are separately controlled by their own thermostats.

The Bottom Line

There is no need to live with uncomfortable rooms. There are steps you and a good HVAC contractor can take to achieve balance in your home’s HVAC system.

We’re here to help at Home Owners Network. Use our ‘Ask the Experts’ service if you need help. Please include as many details as possible about your situation so we can provide you with our best advice.

If you need a qualified technician to help you, try our ‘Find a Contractor’ referral service. Log on to your Home Owners Network account to access the ‘Find a Contractor’ page.


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