INFORMATION
Question: Why does my home get so warm in the summer and cold in the winter?
Answer: Heat Transfer
Let's say you take a glass of ice water and a bowl of hot soup and let them sit out on the kitchen table. You know what will happen: The bowl of soup will cool down to room temperature, and the glass of ice water will warm up to room temperature.
This is a thermodynamic fact of life -- if you put any two objects with different temperatures together, then heat transfer will cause them to reach the same temperature. If you want to keep a bowl of soup hot as long as possible -- that is, if you want to slow down the natural heat transfer process as much as you can -- you have to slow down the three processes that cause heat transfer.
The three processes are:
Conduction – By passing from molecule to neighboring molecule, heat can move through a solid object to an adjoining one, providing the two are touching. A good
example would be a pot touching a hot electric burner on a stove.
Convection – Air motion (currents) can carry heat from warmer surfaces to cooler ones. As air warms, it expands, becomes lighter, and rises, just like a hot
air balloon or the steam (heat) rising
from a hot cup of coffee.
Radiation – Infrared (a form of light) is transmitted by electromagnetic wave motion. This kind of heat transfer is called radiation. Through radiation, heat can jump from warm objects to cooler ones without warming the air in between. Ever stood in front of a window or door wall with sunshine pouring through? The glass may be cool to the touch but you still feel the heat on your skin. Another example is the heat we feel radiating from a concrete wall after the sun has gone down or climbing
up into your attic on a summer day.
Here’s why it is important to block radiant heat
Radiation can account for as much as 93% of all the heat transferred through the attic.
Your regular insulation can’t stop this radiant heat flow.