Why Does My House Heat Unevenly? Common Causes Explored

Freezing Young Girl in Winter Jacket Near a Radiator.

A common problem for homeowners in the DC area is uneven heating. We regularly have metro area homeowners call to ask, “why does my house heat unevenly?”  Once section of their home is warm and toasty, but another area feels like a meat locker.  This is very frustrating for the homeowner because we all want to be able to live comfortably in our whole home. The common causes for this cold zone depends on the type of heating system.


Radiators Heating Unevenly

Older homes in our region often utilize a boiler with radiators. The boiler heats water which travels through the home. In each room, a radiator fills with the hot water and heat the air using natural air currents. In these homes, there are two primary causes for cold rooms.

  1. Blocked Radiator — Radiators rely on air moving under them and rising as it heats. Clothing, books, or furniture blocking the bottom of the radiator causes problems. Decorative covers also block heat coming from radiators. In the early 20th century, it was believed that fresh air would keep disease away. In these homes, they over-sized the radiators and left windows open all winter. As time passed folks realized that it wasted a lot of energy to heat a house with the windows open — so they cut back the amount of heat produced by these older units. They resorted to metallic paint and/or covers. Systems from the mid-twentieth century are not over-sized, so they can be blocked by decorative covers.
  2. Radiators Need Bleeding — Radiators work by completely filling with hot water then heating the air as it flows past the radiator. Occasionally some air slips into the system which means only part of the radiator fills with water — the top portion may be full of air. Releasing this air will allow the entire radiator to fill with hot water. This is called “bleeding” the radiator.

Forced Air Heating Unevenly

Forced air from furnaces or heat pumps can develop cold spots in the home. There are more potential causes for these cold spots, and we’ll work through them one at a time.

  1. Poor Airflow — One of the most common causes for uneven heat in a home with forced air is poor airflow. However, there are many potential causes for the poor airflow.
    • Dirty Filter – if your filter becomes impacted with dirt, it will reduce your airflow which may result in air not reaching some areas of the home.
    • Disconnected Ductwork – if you had renovation work done in some part of the home, renovators may have accidentally (or by taking shortcuts) disconnected the duct run to that room.
    • Blocked Registers – Sometimes piles of clothing, books, toys, or other belongings can be placed on top of floor registers causing the air to be blocked from entering the room.  Similarly, furniture placed in front of wall registers will prevent the air from circulating in the room.
    • Closed Registers – Someone in your family may have closed the register vent without telling you.  Double-check that it is set in the open position.
  2. Doors Closed — Forced air requires the air to enter the room and for the air to be able to return to the furnace via the air return. Your home likely only has a few air returns, so if you close off any rooms, the air will not be able to travel back to the return. This can cause certain rooms to feel cold.
  3. Air Stratification — We all learned as children that heat rises. This means that if left alone, the warm air in your home will rise to the top floor. This makes rooms on lower floors feel colder. You can combat stratification by leaving your fan set to ON and not AUTO.  Setting the fan to ON uses minimal energy (about the energy of a lamp), but saves you from using more energy trying to set the temperature high enough to keep the lower floors comfortable.

If you have any questions you would like answered about your heating system, please call Climate Heating & Cooling at 703-750-4008. If you need a heating system serviced or installed in the DC Metro Area, Climate can make you comfortable. We serve the entire DC Metro Area including towns like Alexandria, Arlington, Fairfax, Potomac, Silver Spring, and Largo. 

Corey Rodgerson

Corey is a third-generation HVAC technician. Both of his grandfathers started in the trade in its infancy and both of his parents continued the tradition with Climate Heating & Cooling. Corey has earned master's licenses as an HVAC Mechanic, Electrician, Gas Fitter, and Plumber. He has been certified in lead remediation, building performance through BPI, and he has completed five NATE certifications for service and installation of HVAC units. He is committed to training and deploying the best technicians in the industry.

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