Walls of Structure Decreasing the Amount of Heat Exchange

Decreasing Power Bill How can we decrease our power bill? How can we decrease our power bill? What are things in our home now that keep our bill low? What are things in our home now that keep our bill low? What are some things we can do to our home to decrease this even further? What are some things we can do to our home to decrease this even further?

Wall Section What are house walls made of? What are house walls made of? If I were to cut a cross section of the wall, what would it look like? If I were to cut a cross section of the wall, what would it look like? What are different materials used to form our walls? What are different materials used to form our walls?

Picking the Material What do you want the appearance of the structure to be? What do you want the appearance of the structure to be? How efficient do you want the structure to be? How efficient do you want the structure to be? How much money do you have to spend? (Now and throughout the life of the building) How much money do you have to spend? (Now and throughout the life of the building)

R value Ranking given to all materials used in walls Ranking given to all materials used in walls A measure of a material’s resistance to heat flow A measure of a material’s resistance to heat flow Higher R value = better the qualityHigher R value = better the quality Better quality means less heat lostBetter quality means less heat lost

Determining R Value Every material has a set value Every material has a set value Value chartValue chart Look at everything included in the wall Look at everything included in the wall List them, find R values, add them togetherList them, find R values, add them together Determine final R valueDetermine final R valuefinal R valuefinal R value

Getting High R Value Pick insulation Pick insulation Largest factor in determining R valueLargest factor in determining R value Amount used can be affected by location, climate, and price (of insulation and utilities)Amount used can be affected by location, climate, and price (of insulation and utilities) Pick your exterior covering Pick your exterior covering Can also greatly affect R valueCan also greatly affect R value

Amount of Insulation to Use

U Value The inverse of the R value The inverse of the R value Measure the the products conductivity of heat Measure the the products conductivity of heat The lower the U value, the better insulating quality of the product The lower the U value, the better insulating quality of the product

“R” Value and “U” Value The “R” value is a measurement of heat loss retardation characteristics of a building component. For example increasing the thickness of an insulating material increases the “R” value. The “U” value is the inverse of “R” value. “U” value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions, and therefore lower “U” value numbers mean higher levels of energy conservation. Both “R” and “U” values are commonly used in building component discussions. The “R” value is a measurement of heat loss retardation characteristics of a building component. For example increasing the thickness of an insulating material increases the “R” value. The “U” value is the inverse of “R” value. “U” value describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions, and therefore lower “U” value numbers mean higher levels of energy conservation. Both “R” and “U” values are commonly used in building component discussions. Source:

How to Use R Value Determine Heat Loss in wall Determine Heat Loss in wall Q = Heat loss Q = Heat loss A = Area of surface A = Area of surface T I = Inside temperature T I = Inside temperature T o = Outside temperature T o = Outside temperature Q = A(T I – T o ) R

Heat Loss Q is figured in units of BTU/hr Q is figured in units of BTU/hr BTU = British Thermal UnitsBTU = British Thermal Units Amount of energy needed to raise the temperature of 1 pound of water 1°FAmount of energy needed to raise the temperature of 1 pound of water 1°F

Heat Loss Figure the amount of heat loss to determine how efficient your home or business is Figure the amount of heat loss to determine how efficient your home or business is More heat lost = higher your power bill More heat lost = higher your power bill More energy needed to replace the heat that is lostMore energy needed to replace the heat that is lost

How is Heat Lost? Through walls and ceilings (roofs) Through walls and ceilings (roofs) Look at R values to determine thisLook at R values to determine this Through windows and doors Through windows and doors Known as infiltration heat lossKnown as infiltration heat loss 35-50% heat loss 35-50% heat loss

Stopping Air Leaks Weatherizing Weatherizing the process of stopping air leaksthe process of stopping air leaks Add storm doors Add storm doors Add storm windows or more panes of glass Add storm windows or more panes of glass Air inside the panes of glass offers additional insulating valueAir inside the panes of glass offers additional insulating value

Caulking / Weatherstripping Filling cracks around anything that penetrates to the outside Filling cracks around anything that penetrates to the outside Variety of types and colors Variety of types and colors Select caulking that has a long warranty and will be remain flexible rather than become brittleSelect caulking that has a long warranty and will be remain flexible rather than become brittle The felt and rubber weatherstriping types are considered temporary, while metal/rubber combination types are more permanentThe felt and rubber weatherstriping types are considered temporary, while metal/rubber combination types are more permanent

Door Thresholds Fastened to the floor under the bottom edge of a door to prevent air leaks Fastened to the floor under the bottom edge of a door to prevent air leaks It may be wood or a combination of metal and rubber.It may be wood or a combination of metal and rubber.

Total Heat Loss of a Building We have a 24’ x 30’ building with 10’ walls. The walls are made of vinyl siding with ½” insulating board, ½” plywood sheathing, 4” of blown in cellulose insulation, and ½” drywall. The walls are supported by 2 x 4 studs that make up 15% of the wall. There is a 2’10” x 6’ 8” wood, 2 ¼” solid core flush door and 10% of the walls are double pane widows with ¼” air space. It also has a ceiling made of ½” drywall and 6” of blown in cellulose insulation. The infiltration rate of the building is 35%. On a 0°F day, what would the heat loss of the building be if it was 70°F inside? We have a 24’ x 30’ building with 10’ walls. The walls are made of vinyl siding with ½” insulating board, ½” plywood sheathing, 4” of blown in cellulose insulation, and ½” drywall. The walls are supported by 2 x 4 studs that make up 15% of the wall. There is a 2’10” x 6’ 8” wood, 2 ¼” solid core flush door and 10% of the walls are double pane widows with ¼” air space. It also has a ceiling made of ½” drywall and 6” of blown in cellulose insulation. The infiltration rate of the building is 35%. On a 0°F day, what would the heat loss of the building be if it was 70°F inside?

Total Heat Loss of a Building The walls are made of vinyl siding with ½” insulating board, ½” plywood sheathing, 4” of blown in cellulose insulation, and ½” drywall. The walls are supported by 2 x 4 studs that make up 15% of the wall. The walls are made of vinyl siding with ½” insulating board, ½” plywood sheathing, 4” of blown in cellulose insulation, and ½” drywall. The walls are supported by 2 x 4 studs that make up 15% of the wall. R =

Total Heat Loss of a Building We have a 24’ x 30’ building with 10’ walls. We have a 24’ x 30’ building with 10’ walls. 2’10” x 6’ 8” door 2’10” x 6’ 8” door 10% windows 10% windows A = 1080 ft 2 A = ft 2 A = ft 2

Total Heat Loss of a Building Inside temperature is 70°F and outside temperature is 10°F Inside temperature is 70°F and outside temperature is 10°F Heat loss of wall Heat loss of wall T = 70°F Q = BTU/hr

Total Heat Loss of a Building Heat loss of window Heat loss of window Heat loss of door Heat loss of door Q = BTU/hr Q = BTU/hr

Total Heat Loss of a Building It also has a ceiling made of ½” drywall and 6” of blown in cellulose insulation. It also has a ceiling made of ½” drywall and 6” of blown in cellulose insulation. Ceiling area Ceiling area R = A = 720 ft 2

Total Heat Loss of a Building Heat loss of ceiling Heat loss of ceiling Heat loss of all parts of the building Heat loss of all parts of the building Q = BTU/hr Q = BTU/hr

Total Heat Loss of a Building The infiltration rate of the building is 35%. The infiltration rate of the building is 35%. Overall Total Heat Loss Overall Total Heat Loss Q = BTU/hr Q = BTU/hr