How To Balance a Forced Air Furnace


As the name implies, forced air furnaces push air into vents to warm the home. The air then returns to the furnace to be reheated. However, you may notice the air flow lacks balance in certain rooms of the house, especially in two-story houses. Follow these steps to balance your forced-air furnace.

Open All Dampers

First, if your home doesn't have in-room thermometers, place a thermometer in each room that seems too hot or too cold. Next, find the main furnace ducts. These should be located in the basement, attic, a crawl space, or utility room. Determine what ducts connect to certain rooms, and label them with a marker. Locate the damper on the ductwork, a flat or round metal plate attached to the duct or long handles. If the dampers are open, their handles will sit parallel to the top and the bottom of the duct. A handle pointing across the duct means the damper has blocked most air flow. To fully open your dampers, rotate the plate or handle on each damper to the right until it no longer turns. 

Check the temperature on each thermometer after one hour. If some rooms are still too warm, partially close the damper to those rooms by turning the handle or plate until it comes one-third between vertical and horizontal, then check the temperature again. Keep turning the handle or plate in one-third increments until you get the room to the desired temperature. 

Also, ensure that the registers aren't blocked or dirty and that the metal flaps are open. Open the register flaps by rotating a lever on the side of the register.

Balance Thermometers

If the thermometers still aren't around the same temperature, disconnect them from the wall. Place them together in the same room, and leave them for half an hour, noting variations. This will determine whether any thermometers aren't calibrated properly.

Next, attach or tape the thermometers three feet from the floor away from the return air vent. Let the furnace run for an hour, and check the readings, adjusting the dampers until you get the balance you want. 

After you get the balance, mark a line on the duct at the handle's current position, and label it "WINTER". When the weather warms, repeat the task, and mark the line for "SUMMER". 

Adjust the Blower Motor

Sometimes, the blower motor gets out of alignment, causing an unbalanced system. Locate the blower motor, which is commonly inside a squirrel cage, or refer to the manual.

To check the balance, lay a carpenter's square against the outside of the motor and pulleys, which should form a straight line, and come at a right angle to the motor shaft. To adjust the pulleys, loosen the set screw with a screwdriver, and position the pulleys forward or back as needed. 

For more help with balancing your system, contact a residential heating professional near you.


26 March 2018

cleaning the air in your home

The quality of the air in your home is something that you should keep in mind every day. If the air that you breathe each day is filled with impurities, it can cause you to get sick more often and complicate matters if anyone in your home suffers from asthma or allergies. This blog is all about purifying the air in your home. You will learn everything about filtration systems and filters for your heating system to what you can do around the home to keep the air as clean as possible and create a healthy living space for your family.