SAN DIEGO, CALIFORNIA- A frequent complaint from homeowners is that certain rooms are too cold in the winter and too hot in the summer while the rest of the house is comfortable. Some people know them as hot and cold spots.

A small variation in temperature, two or three degrees, between rooms is normal and does not necessarily mean there is a problem with the heating and air conditioning system. But when the difference is closer to five or 10 degrees, there is a problem, according to Gabriel Carini, an expert in heating and air conditioning repair and installation.

Instead of running the HVAC system more often and longer, racking up on energy costs, homeowners can turn to Carini Heating, Air and Plumbing for suggestions on fixing the problem.
Carini, a heating and cooling pro, explains several common causes of hot and cold spots and gives practical solutions for do-it-yourself fixes, but he also offers complete home comfort inspections for more complex troubleshooting.
Causes Of Cold And Hot Spots
There are several factors that could be in play with inconsistent temperatures in a home.

  • An incorrectly-sized HVAC unit for the space being heated and cooled
  • Indoor comfort system efficiency
  • The number and placement of vents in a room
  • Ductwork configuration and size
  • Leaky ductwork
  • Less than the recommended level and type of insulation or improperly installed insulation
  • Bad location for the temperature control
  • Placement, type and condition of doors and windows
  • Physical position of the building structure
  • Exterior landscaping, including trees

Heat rises by convection, so no matter what time of year, the warmest areas in a house will be the rooms that are highest, such as upper stories of a multi-story home or in rooms with vaulted ceilings, Carini explains.

Suppose the home office is on the second story of a two-story home with two windows- one south-facing, one west-facing with no window treatments. There might be an issue with the ductwork; perhaps the duct to that room is not big enough or leaking. Or the ducting might be done perfectly, but the attic does not have the recommended amount of insulation, which allows the heat to radiate down into the office. In addition to that, the sun beats through the windows all day, heating the room up.
Solutions range from simple, do-it-yourself projects to professional upgrades to the home’s structure.

The goal is to reduce the sun load, which can be done by tinting an existing window or replacing windows with Low-E glass. Both save energy and reduce the amount of time the HVAC unit is running.

“Homeowners might not be able to reconfigure ductwork or check for leaks, but adding blinds and drapes are within almost every budget and level of expertise. They may be surprised at what a difference that alone makes,” says Carini, an expert in heating repair in San Diego. Alos San Diego residential property owners can save on energy costs and increase the value of their homes by upgrading windows to more energy efficient ones.

Since the thermostat reads the temperature in the room where it is located, some people use multiple programmable thermostats and damper controls, so each room and area in a home can be programmed to be heated or cooled individually, potentially another big money-saver ( This can be one way of combatting pesky hot and cold spots, but it is not the solution for every home, particularly older homes.

It is common for 40 percent of a home’s conditioned air to escape through the attic because there is not enough insulation ( Adding attic insulation provides a continuous thermal barrier that minimizes heat flow through the ceiling, which might be what is heating up certain rooms in a home and not others.

“If structural frame elements such as ceiling joists or wall framing boards are visible, you probably need more insulation,” says Carini, an AC repair professional. “Most homes do not have the recommended amount.”

Temperature variations between rooms can result from ductwork that has been improperly installed, including joints that are not insulated, one duct feeding two that branch off and incorrect size or duct for the needed air flow. Leaky ducts allow hot attic air to be sucked into the supply ducts during the summer and blown into upstairs rooms.

The Carini repair and installation field technicians are experts trained to investigate these issues, determine the causes, and make the repairs and improvements to ensure year-round comfort, improved energy efficiency and lower utility bills.

For more information about energy efficiency in your home, visit the Alliance To Save Energy site for a home energy audit worksheet. The U.S. Department of Energy also has a Do-It-Yourself Home Energy Assessment that can help fix problems in a home that cause comfort problems.