There always seems to be one room in your home that is colder then the others and in the summer that same room seems to be the hottest. In this HowTo we will look at some of the cures for improperly balanced heating systems along with other problems that can cause this uncomfortable situation.
Gas forced hot air systems have been around for decades and they are used in residential and commercial buildings to provide a somewhat cheap and reliable heating delivery system.
At your Furnace you have a gas burner and a blower that circulates cold air from your living space through the heater and back out through your ducts and vents. In order for this system to work correctly you must have a heater that is large enough to feed your home and its circulation path must work properly to feed the correct amount of heated air to each room.
If you go down into your basement or look in your crawl space you will see that your heater duct starts off large near the heater and then gets smaller as it reaches more distant rooms. If you have a two story building you may have a shaft called a plenum that provides a large amount of heated air to your second floor. It is often hidden in your walls probably part of a closet that you don’t notice.
.
Insulation and Sealing Heating Duct Joints
All of the duct work that is not in a heated space …. the ducts under your home in a crawl space or ducts that go through your attic to deliver hot air must be insulated. Insulated duct is available but additional insulation should be laid over or surrounding the duct in attics and crawl spaces.
In addition to insulation each break between ducts must be sealed with aluminum duct tape and each screw that is inserted to attach a hanger should be caulked or taped.
There should be absolutely no leaks in your feed lines or you will be heating spaces that don’t need heat and reducing flow where it is needed.
Zoning The Duct System
For a HVAC system to work correctly it needs to supply the right amount of airflow to each room ducts that start at the furnace are larger in size and as they reach the outer rooms get smaller. You will also notice that larger ducts are made out of square sheet metal and feeder ducts to each room are made of round tube or a flexible round line.
In addition to zoning by sizing the duct there are also flappers installed in your feeder ducts. This allows you to cutoff part of the flow to rooms closer to the heater and provide more pressure to the remote rooms.
To properly zone the most remote rooms you need to adjust all of the flappers or dampeners throughout the main duct work.
In addition you may find that fine tuning is needed. This is where the vents in the floor or sidewalls in each room that deliver the hot air can be adjusted.
In the winter you may find that you can close down some of the vents in your basement. This will depend on how much you use your basement but because it is below ground only a small amount of heat is necessary to keep it above 60F and protect your water service and waste pipes.
You may also want to reduce heat to your kitchen, utility and bathrooms at night to increase heat to your bedrooms. If you do this make sure that there is a good supply of heat to the area around your thermostat or you will find your heater running all night and your bedrooms getting hot while the rest of the house is not. Testing will be required.
Return Ducts
Returning the air to the heater is just as important as providing enough air to the room you are heating. Some bedrooms and other smaller rooms may not have a return duct in them and this can be one reason a single room is cold in your house.
Often Bedrooms that have their doors open during the day are fine but at night when they are closed the air that is being forced into them by the supply ducts has no room to flow and is restricted by pressure.
An example of this would be opening one window in your home on a breezy day. The wind may not flow into the window that much but if you open a window on the opposite side of your home you will find the path of air coming in has a free way to push its way through your home. The same is true on a car.
Final Note
It is important to have your furnace set up correctly with its duct system designed to perform correctly for the spaces you need heated and cooled.
Lack of return ducts, insulation and leaky supply ducts can really reduce air quality and dampening flaps that are located in main ducts and feeder lines could cause restriction.
Taking an afternoon to examine how your system is performing and making these small adjustments will improve the comfort in your home and may save you money.
Also remember to take into account that rooms that are on the north side of your home won’t get as much sun during the day and this will lower the amount of heat that is stored in furnishings, walls and floor surfaces then radiated out at night.