Many people think that comfort is defined by two things and two things alone: temperature and humidity. But there is a lot more to it than that. The American Society of Heating, Refrigerating and Air Conditioning Engineers lists the seven factors that influence comfort as:
- Activity Level
- Type of Clothing Worn
- Your Own Expectations of Comfort
- Air Temperature
- Radiant Temperature
- Air Speed
We’ll be looking at these in more detail to help you understand how you can stay as comfortable as possible all year long.
Your body produces its own heat all day and all night in an effort to keep your core and skin temperatures stable. You’ve probably noticed that the more you move around during the day, the warmer your body gets.
Body temperature is controlled by a process called metabolism, and a standard unit of measurement for activity level is called a “met.” One met is equal to the amount of heat you put out while seated at rest and increased based on your activity level.
Type of Clothing Worn
The type of clothing you wear influences the amount of heat kept close to your body, and can help you feel cooler in warm temperatures and warmer in cold temperatures. Clothes act as insulators, and the amount of insulation provided by each piece of clothing is measured in a unit appropriately called a “clo.” Your HVAC technician will use information about the type of clothes you wear to determine the comfort level of your home.
Your Expectations of Comfort
This way seem surprising, but how comfortable you expect to feel will have a big impact on how comfortable you actually feel! Consider these three examples:
- You come back home during the summer and expect your air conditioning to be on and your home to be at your exact comfort level.
- You walk into a movie theater and expect it to be cool, regardless of the temperature outside.
- You walk into a dormitory or apartment building with lots of open windows. You expect it to be cool inside, but not as cool as your home or the movie theater.
If you anticipate the conditions inside these and other types of buildings, you are more likely to be comfortable than if you are surprised by how warm or cold it is indoors. You may even find yourself comfortable in a room with access to a thermostat, even if that thermostat doesn’t work!
When we’re talking about your comfort, the words “air temperature” refer to the temperature wherever you are, right now. The temperature can fluctuate over time and may vary from your head to your feet!
Heat energy always moves from warm surfaces to cool surfaces until their temperatures are equal. Radiant heat describes this exact thing: heat moving from a warm object to a cool object without affecting the space in between.
In most cases, the walls, floors, and ceilings will be pretty close to the air temperature and you probably won’t notice any differences in the radiant temperature. Where you will notice it is if you sit close to a window on a cold day—now, the radiant temperature near the window will be much lower than in the rest of the building.
Radiant temperature comes into play when assessing your insulation needs and is the major factor in radiant floor heating.
Humidity, or the amount of moisture present in the air, is a tricky one because the humidity level needs to be within a certain range for you to feel comfortable. Low humidity can lead to problems like dry skin and eyes and static electricity. High humidity means you have far too much moisture in the air, which can lead to problems with mold and mildew growth and can cause water damage to your furniture and other items in your home.
Any time air moves across your body—be it from a breeze, a fan, or anything else—you will feel cooler, and the faster the air moves, the cooler you’ll feel. Drafts are caused any time air speed gets too high or if you have fast-moving air and cold temperatures. Drafts are more noticeable when they blow across your head or feet, which typically have less clothing protection.
At Michael Bonsby Heating & Air Conditioning, we take all of the above factors into account when designing your home’s comfort systems. For an HVAC installation in Maryland or Washington, DC, call us today!