Comfort is a key word when it comes to describing the interior of a home. Comfort, in this column, relates to heating and cooling.
Most homes in this part of the country heat in the winter and cool in the summer. Heating and cooling are two different functions when it comes to moving air. Hot air is “light” and easier to move than cold air, which is heavier. That is the reason why your furnace fan runs faster in the summer than it does in the winter. Moving those two different types of conditioned air just might be the reason why your home may seem to have a more balanced comfort level during the winter than in the summer or the other way around.
Heating and cooling systems go way beyond selecting a furnace box and maybe an air-conditioning compressor. That selection process might include a geothermal unit, which might consist of a loop of tubing all around your yard, or perhaps two drilled water wells, which are used to bring well-temperature water to your unit and return the water back to the ground through the second well. You might think about a heat pump system, which uses outside air to extract either warmer air or cooler air from outside to condition the inside air.
Most homes heat with gas or electric, warming the air that moves through the furnace and distributing it throughout the house through ducts placed in almost every room. To complete the circulation loop, cold air returns are needed to supply air to the furnace to be looped back through the home again and again. It sounds simple, but there is more to it than that.
Air distribution is a science very important to every home’s design and the efficiency of your equipment, your money and your comfort. In other words, for you to get the most from your equipment your builder, your salesperson and/or installer needs to do some work such as a whole house “load calculation” or a complete evaluation including running your home’s measurements through a Manual D program.
All this takes lots of time and usually means many homes require different-size units not always in stock. You should have to pay for the pre-evaluation by your chosen contractor, because he or she may not get the job if you look for second or third opinions. Too big a unit may cost you more than you might think. Too small a unit might produce a big disappointment. Either mistake can cost you more money than you should have to spend heating and or cooling.
If you already own a home, always think about or even write down what comes to mind about the comfort levels in various rooms. Note cold or hot spots. Think about where your registers are located. Most of the time, registers are either under or over windows, which is done to help combat condensation issues since windows can be colder than the walls of a room and can condensate moisture on the cooler windows or window frames.
Think about your furniture. Many times air flow can be blocked by furniture, which can make a room feel too warm in one place and or too cool in another.
Registers diffuse air flow, which means they direct the air one way or another. They almost always have shutters that can control the amount of air flowing out. I always tell my inspection clients to remember that registers do come in many different colors and might be called designer units, but the most important part of a register is how to “diffuse” the air and in what direction(s). A different register alone might help improve the comfort balance in a room by directing the air one way or the other.
A properly-sized heating and cooling system includes properly-sized supply and cold air return ducts as well. Not every room will need the same amount of conditioned air. You should not have to adjust any one room’s air flow using the register. If everything is sized correctly, your entire home can be balanced for comfort.
Closing off an unused room can also be a mistake. You might close an unused bedroom register and door, not thinking about the cold air return, which would continue to draw much colder air back to your furnace. Maybe that bedroom doesn’t have a cold air return. If that is the case, there should be space between the bottom of the door and the floor to provide incoming air pressure to escape the room if the door is closed.
If there is no air gap and/or no cold air return in that room, when the furnace is running, the room will pressurize and no new air will flow in. That extra flow of air will end up going somewhere, which may disturb a comfortable balance somewhere else in your home.
Thermostat location and or remote sensors can sometimes help with heating and or cooling balance. During one inspection, I noticed a lamp right under the wall thermostat. When the lamp was on, the heat from the light helped warm the thermostat, suggesting the home was warmer than it really was. Don’t let that happen to you.
