Insulation and Interior Inspection Section#1 Insulation and Ventilation Quiz#4

This study session covers the control of moisture flow in homes in both heating and cooling climates. The estimated completion time for this study session is forty-five minutes. Objectives At the end of this study session, you should be able to: Rank air leakage and vapor diffusion in importance with respect to moisture problems in homes. List two common air/vapor barrier materials. Explain in two sentences how sheathing and roofing materials have affected air leakage in homes. Name one important difference between housewrap and building paper. Explain in two sentences how windows affect moisture levels in homes. List two advantages and two disadvantages of exhaust fans. Explain in two sentences how direct-vent furnaces affect moisture levels in homes. Describe in three sentences how heat recovery ventilators (HRVs) work. List six components of HRVs. List two different types of ventilation systems in homes. Describe in one sentence the source of moisture that can cause condensation damage in homes in hot, humid climates. Indicate where the air/vapor barrier should be in a wall system in a hot, humid climate. Question 1 Needs Grading Describe the source of moisture that can cause condensation problems in walls in hot climates. Selected Answer: The source of moisture that can cause condensation problems in walls in hot climate is on the outside of the house.  Correct Answer:   Outside or exterior to the house ? the warm, humid air leaking into the cool air-conditioned interior Response Feedback: [None Given] Question 2 Needs Grading How do modern windows affect moisture levels and moisture control in homes? Selected Answer: Modern windows don't lose heat as quickly as older windows (although their R-values are still quite low). There is not much condensation on windows as quickly as old windows. It doesn't show clearly the humidity level as old windows do. The reduced air leakage through and around new doors and windows leads to higher indoor humidity levels.  Correct Answer:   Modern windows fit tighter, and do not allow moisture to escape. Since they are double or triple paned units, the inner pane is warmer, which makes it more difficult to detect moisture build-up inside the home. Response Feedback: [None Given] Question 3 Needs Grading How have induced draft fans and direct vent furnaces affected moisture levels in homes? Selected Answer: With these appliances, the need to maintain positive indoor air pressure is diminishing.  Correct Answer:   We don?t have to worry about backdrafting, so we can use our fans and HRVs to control moisture. Response Feedback: [None Given] Question 4 Needs Grading How have modern wall and roof sheathings affected air leakage in modern homes? Selected Answer: They allow much less air into and out of the wall Correct Answer:   They have further reduced air leakage. Response Feedback: [None Given] Question 5 Needs Grading How is housewrap different than building paper? Selected Answer: Housewrap is tightly fit. It restricted air movement while allowing vapor diffusion through.  Correct Answer:   Housewrap fits tighter to the wall, with fewer joints and restricts air movement while allowing vapour diffusion. Response Feedback: [None Given] Question 6 Needs Grading Indicate where the air/vapour barrier should be located in the wall assembly in a hot, humid climate. Selected Answer: It should be located outside of the wall.  Correct Answer:   Outer part of the wall, or not at all Response Feedback: [None Given] Question 7 Needs Grading List six components of a heat recovery ventilator. Selected Answer: 1. An HRV contains two duct systems. One collected exhaust air from the house and pushes it outside. The second draws fresh air into the house. Fans move the air into and out of the house at the desired rate.  2. A heat exchanger captures some of the heat from the exhaust air and transfers it to the incoming air.  3. A defrost mechanism removes ice from the heat exchanger.  4. Balancing dampers and flow collars allow the system to be adjusted.  5. A drain carries away condensed humidity and melted frost.  6. Controls determine the speed of fans and the volume of air moved, depending on manual controls, humidistats and/or times.  Correct Answer:   1. Two duct systems and fans to move air 2. Heat exchanger 3. Defrost mechanism 4. Balancing dampers and flow collars 5. A drain 6. Controls for fan speed and amount of air movement Response Feedback: [None Given] Question 8 Needs Grading List two advantages of exhaust fans in homes. Selected Answer: 1. Kitchen and bathroom fans throw out moisture with that air - moisture that could damage the building envelope.  2. Exhaust fan lower the air pressure inside, relative to the outdoors. In cold climates, warm dry air leaking in through the walls isn't a problem.  Correct Answer:   1. They throw out more moisture than air 2. Lower air pressure inside, which increases dry air movement through walls and roofs Response Feedback: [None Given] Question 9 Needs Grading List two common air/vapour barrier materials. Which one is more commonly used today? Selected Answer: 1. Kraft paper was used in old days.  2. Polyethylene films are commonly used today.  Correct Answer:   1. Kraft paper 2. Polyethylene films (more modern) Response Feedback: [None Given] Question 10 Needs Grading List two disadvantages of exhaust fans in homes. Selected Answer: 1. Exhausting air from the house wastes energy.  2. The lower indoor air pressure can cause backdraft of combustion appliances.  Correct Answer:   1. Wastes energy, heated air thrown outside 2. Can cause backdrafting of combustion appliances Response Feedback: [None Given] Question 11 Needs Grading The term ventilation might mean two very different things with respect to homes. Explain the two different types of ventilation. Selected Answer: 1. Venting walls and roof spaces to get rid of moisture that can cause damage to the structure.  2. Venting indoor living spaces to improve the air quality. Removing excess moisture in the air.  Correct Answer:   1. Venting of roof and wall spaces to flush warm moist air out of the building components 2. Exhausting stale air and supplying fresh air to the living space Response Feedback: [None Given] Question 12 Needs Grading What is the purpose of a heat recovery ventilator? Selected Answer: 1. Remove some of the heat from the air before we exhaust it.  2. Control the location and amount of fresh air drawn into the house.  Correct Answer:   To transfer some of the heat from the air exhausted from the house into the fresh air coming into the house Response Feedback: [None Given] Question 13 Needs Grading Why are roofs vented in the winter in cold climates? Selected Answer: To stop leakage of warm, moisture air into cool roof spaces.  Correct Answer:   We were not able to completely stop air leakage into cool roof spaces, so we need to get rid of that warm, moist air. Response Feedback: [None Given] Question 14 0 out of 0 points Which is more important with respect to moisture problems in homes? Selected Answer:   air leakage Answers: vapour diffusion   air leakage Response Feedback: Good work