Lesson Overview

Students will learn about heat transfer and the building design engineering that limits heat loss. Students will calculate the heat loss of a building within various climate zones. Students will determine which insulation material works best in certain climate zones.

Target Grades: 6-12 / 6-8 / 9-12

Set Up Time: 30 minutes

Class Time: 1.5 hours

Lesson Resources

Objectives

1. Design house insulation using real-world builder equations

2. Calculate the insulation R-value and heat loss of various areas of the house

3. Calculate how much energy can be conserved by turning down the thermostat.

4. Compare and recognize differences between calculated and actual values

Guiding question: How can we use heat loss calculations to help determine insulation decisions?

Educational Standards

ALASKA CULTURAL STANDARDS: B4

ALASKA MATHEMATICS STANDARDS: 6.RP.1-3; 6.NS.1-3; 6.EE.2; 6.EE.6; 7.RP.1; 7.RP.3, 7.EE.3; 7.EE.4

ALASKA DIGITAL LITERACY STANDARDS: 6-12.CT.3

ENERGY LITERACY CONCEPTS: 1.2, 1.7, 5.3, 6.8

NGSS: MS-PS3-3

Lesson Preparation:
  • Read the Background section below
  • Collect the necessary materials
  • Print one Calculating Heat Loss worksheet per student
Gather Materials:
  • One Calculating Heat Loss worksheet per student
  • Calculators
  • Graph paper
  • Pens/pencils

The U.S. Energy Information Agency reports that homes and commercial buildings use 71% of the electricity in the United States and this number will rise to 75% by 2025 (http://www.nrel.gov/buildings/). According to the Alaska Energy Authority’s 2012 End Use Study, the majority of energy consumed in residential buildings in Alaska is used for heating (80% in the Railbelt and Southeast Alaska and 72% in Bethel).  Significant energy and cost savings can be achieved through proper building design and use of energy efficient appliances and systems.  The Alaska Legislature has adopted an energy efficiency goal of 15% energy use reduction by 2020 and the U.S. Department of Energy has a specific target to make new and existing homes 40% more energy efficient by 2025 relative to 2010 (https://energy.gov/eere/buildings/downloads/multi-year-program-plan).

Heating is the single largest energy use for homes in Alaska. Homes need proper insulation as a barrier between the outside elements and a comfortable indoor living environment. The amount of recommended insulation needed depends on a building’s location– Alaska is divided into four climate zones. The Alaska Housing Finance Corporation (AHFC) has developed a set of energy standards called BEES (Building Energy Efficiency Standard) that specifies the minimum amount of insulation needed for AHFC-financed buildings in the four zones. BEES is based on the International Energy Conservation Code.

BEES – Alaska Building Energy Efficiency Standard

The Alaska Building Energy Efficiency Standard was established by the State of Alaska to promote the construction of energy efficient buildings. It sets building energy use standards for thermal resistance, air leakage, moisture protection and ventilation. BEES is currently comprised of the 2009 International Energy Conservation Code (IECC), ASHRAE 62.2 2010 and Alaska Specific Amendments to both.  All new residential homes and community-owned buildings which began construction on or after January 1, 1992 must comply with BEES if AHFC or other state financial assistance is to be used in construction or the purchase of a loan.

Measurements of surface area, insulation, and temperature gradients can be plugged into this heat loss equation to calculate how much heat will be lost through the walls, windows, and other parts of a building.

British Thermal Unit (BTU) – A unit used to measure energy.  It is the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit and it is equivalent to 1055 joules.  A BTU is approximately the amount of energy that one match stick gives off. 

Building Energy Efficiency Standards (BEES) – Building standards established by the State of Alaska for new homes that are constructed with financing through Alaska Housing Finance Corporation. The BEES promote the construction of energy efficient buildings by setting standards for thermal resistance, air leakage, moisture protection and ventilation. 

R-Value – A measure of how well a material insulates and resists heat transfer.  It is a term used in the construction industry to rate a building’s insulation in its roof, walls, and foundation. A high R-value indicates greater insulating effectiveness; the higher the R-Value, the better the building is able to retain heat inside or resist heat from outside.

Temperature Gradient (Δ T) – The difference in temperature between two places (i.e. inside a building and outside the building) that dictates which direction and at what rate heat energy will move. 

U Factor – A measure of how well a material conducts heat, usually used in reference to a building’s windows. A material’s U Factor is the inverse of its R-value: U Factor = 1/R-value, so a high R-value is equivalent a low U Factor.

Gear Up:
  • Have students brainstorm the different planning aspects when building the frame and insulation of a house.
    • What is insulation? How does it work?
    • What materials do you think are good insulators? Which ones do you think are bad insulators? How can you tell?
    • How can they determine how much insulation is needed? 
Activity:
  • Students will be guided through new concepts and formulas about insulation and heat loss with the Calculating Heat Loss student worksheet. This worksheet can be done individually or in pairs.
  • Distribute one copy of the worksheet and facilitate the activity detailed on the worksheet. 
  • Depending on the level of your students, they might be able to work on it themselves or they might need some more guided facilitation to complete the worksheet. Adjust the facilitation style according to your students and simplify or elaborate as needed.
  • After students finish working on the worksheet, wrap-up and conclude the activity by giving students an opportunity to explain, reflect, expand and apply what they learned. You can do this by guiding a discussion or asking students questions.
    • What surprised you the most while doing this activity?
    • What are you taking away from this lesson?
    • How can you apply what you learned at home or school?
Extension:
  • Have students collect data by estimating the surface area and insulation of their own house. Use the equations provided in the worksheet to have students calculate the heat loss from their own homes.
  • This activity can be used as the pre-requisite for Designing your Energy Efficient house Part Two: Modeling Your Energy Efficient House.
Evaluation:

Ask students to:

  • Define the units for insulation like R-value and U-factor
  • Complete and submit the Calculating Heat Loss worksheet