Designing Your Energy Efficient Home

Name______

When building a house, a builder must determine if he or she is using the correct materials and building techniques for the location. This worksheet will walk you through the types of calculations that builders must make in order to construct a house that protects the occupants from the outside climate.

R-VALUE

The R-value of an insulating material tells you how well that material insulates (or its ability to resist heat from going through; the “R” stands for “resistance”). The larger the R-value, the better the material insulates. For example:

The R-value of wood is 2 per 1-inch of thickness while sawdust has an R-value of 3 per 1-inch of thickness.

1. Which is a better insulator—wood or sawdust? ______

Why? ______

Total R-value = (R-value per inch) X (thickness of material)

2. What is the R-value of a 5 inch thick wood wall? ______

3. What is the R-value of sawdust insulation in a wall that is 5 inches thick? ______

4. Calculate the surface areas of the house—you can use graph paper to draw out each side of the house to help calculate the different surface areas. Assume that the two walls that you can’t see are identical to the two that you can see.

Door—total surface area of two doors: a front door and a back door (each door is 3 ft. wide by 7 ft. tall) / Sq. ft.
Windows—total surface area of all windows (eight windows: two 3 ft. x 3 ft.; six 3 ft. x 4 ft. / Sq. ft.
Exterior walls—total surface area (minus the doors and windows; use the formula for the area of a triangle to calculate the exterior wall sections under the pitched roof: A = ½ x b x h) / Sq. ft.
Roof—total surface area / Sq. ft.

A large house (with a larger surface area) loses more heat than a smaller house (with a smaller surface area). Windows lose more heat than doors or walls.

Would a larger house or a smaller house be better for saving heat? Why?

Would a larger window or a smaller window be better for saving heat? Why?

Go to AKEnergySmart.org/web-lesson/question1.html and design your own energy efficient house!

For round 1, choose your region and design a house that you would really want.

For round 2, try to maximize your savings after 25 years.

For round 3, pick a different region and design a house that you would want.

Summary of choices:

Round 1 / Round 2 / Round 3
Region
Cost of Heating Fuel
Cost of Electricity per kWh
Building Budget remaining
Annual Energy Bill Amount
Cost of Energy Bills over 25 years
Savings after 25 years

What did you do differently for the second round? Why?

Which round did you end up with more savings after 25 years? Why?

What could you buy with your extra savings (from whichever round gave you the most)?

3

AK EnergySmart: Designing Your Energy Efficient House Web Activity