Conduction Heat Loss

Conduction Heat Loss jls164

Main Factors of Heat Loss

What does a house's heat loss depend on? Complete the activity below to find out the three main factors leading to heat loss.

Conduction Heat Loss Activity

Main Factors of Heat Loss

What are the three main factors a house's heat loss depends on?

Example 1:

House A sits next to house B. Though both houses have the same basic design, house B is significantly larger than house A.

  1. Which house loses more heat?
    1. House A
    2. House B
  2. Why do you think this house loses more heat?
    1. More people in it
    2. More appliances and lights are used
    3. Larger size/more area

Example 2:

House A and house B are the exact same size and design. House A sits on the beach in a warm, tropical area, while house B sits by a ski resort in the mountains up north, surrounded by snow.

  1. Which house loses more heat?
    1. House A
    2. House B
  2. Why do you think this house loses more heat?
    1. People skiing need more heat to keep warm
    2. Snow on the roof is good insulation
    3. Outside temperature

Example 3:

House A and house B are the same size and sit next to each other. The design for both houses is the same, except house A has a thick layer of pink insulation installed. The R-value of house B is .63 and the R-value of house A is unknown.

  1. Which house loses more heat?
    1. House A
    2. House B
  2. Why do you think this house loses more heat?
    1. Less insulation
    2. It's only one color
    3. It's thicker

Answers:

Example 1:

  1. B: House B
  2. C: Larger size/more area

Example 2:

  1. B: House B
  2. C: Outside temperature

Example 3:

  1. B: House B
  2. A: Less insulation
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Most heat is lost through a house's walls through conduction. As you learned from the activity on the previous screen, the amount of heat loss depends on three factors:

  • Size of the house (area through which the heat can escape)
  • Local weather or climatic conditions:
    • The inside temperature is often constant at a comfortable temperature of 65°F.
    • As the outside temperature falls lower than 65°F, the heat is lost to the outside.
    • The higher the temperature difference, the higher the heat loss to outside.
    • By calculating the Heating Degree Days (HDD), we can determine how many degrees the mean temperature fell below 65ºF for the day.
  • Wall's capacity to resist heat loss.
    • Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow.
    • The higher the R-value, the greater is the insulating effectiveness.