Residential Energy Audit - Chapter 3

1. CFM is the unit of measurement for cubic feet per minute. What does CFM50 refer as a read out from a blower door test.?

Cubic feet per minute divided by half of the air pressure in the home

Cubic feet per minute at 50 pascals of house pressure

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2. The pressures created by stack effect is greatest at the ____________ points.

Highest and lowest

Mid

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3. ASHRAE suggests a minimum ventilation rate of _____ CFM per person or 0.35 ACHn, whichever is greater.

1

15

30

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4. The wind, furnace blower and stack effect tend to pressurize some areas of the home and depressurize others.

True

False

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5. During a blower door test you can also pressurize the home instead of depressurizing it, and then observe the attic floor from the attic to spot signs of air blowing through the ceiling into the attic.

True

False

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6. Exhausts fans and cloth dryers move the neutral pressure plane up because more of the interior space is under negative pressure.

True

False

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7. The wind speed ____________ the higher from the ground you measure.

Decreases

Increases

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8. The wind is blowing at 40mph. The leeward side, facing away from the wind, is usually either ______________ or ______________.

Pressurized, neutral

Depressurized, neutral

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9. Depressurization of a combustion zone is often set at ______ pascals with reference to the outdoors.

-3 to -5

-5 to -10

-15

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10. Depressurization limit of a combustion zone is often set at -3 to -5 pascals with reference to the __________.

Outdoors

Indoors

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11. What does the acronym "MVG" stand for?

Maximum Ventilation Guideline

Minimum Ventilation Guideline

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12. ASHRAE suggests a minimum ventilation rate of 15 CFM per person or ____ ACHn, whichever is greater under natural conditions.

0.53

0.45

0.35

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13. The _________ combined with the ___________ defines the thermal boundary.

Air barrier

Insulation

Walls

Attic

Crawl space

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14. Indirect air leakage occurs at:

Windows

Doors

The building shell

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15. Exhaust fans and cloths dryers create a slight vacuum and therefor also move the neutral pressure plane _____.

Up

Down

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16. Why does the neutral pressure plane move up when a cloth dryer is turned on?

The buildings interior space is under more negative pressure.

The buildings interior space is under more positive pressure.

The neutral pressure plane is always in the middle and never moves up or down.

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17. A hole near the neutral pressure plane of the home allows an ______________air leakage.

Minimal

Average

Excessive

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18. A home must have sufficient air leakage or whole house ventilation.

True. Either one is very effective in providing the home with fresh air.

False. Only whole house ventilation can provide adequate fresh air inside the home.

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19. What is the area between positive and negative pressure in a home called?

Neutral zone

Neutral pressure zone

Neutral pressure plane

Zero pressure zone

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20. A single family home with a blower door flow reading of 1500CFM50 _________________________________.

Leaves a lot of room for improvement.

Is hard to improve on.

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21. Indicate which of the following is NOT part of preparations and setup of a blower door test?

Closing primary windows and storm windows

Closing all interior doors

Disabling heaters and water heaters by turning down their thermostats.

Covering ashes in wood stoves and fireplaces with damp newspaper to prevent the ashes from being sucked into the home.

Shutting fireplace dampers, fireplace glass doors, wood stove dampers, wood stove air intakes.

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22. Indicate the correct measurement for air leakage through construction materials.

CFM

CFM25 per 100 square ft

CFM50 per100 square ft

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23. A fan that forces air into the home moves the neutral pressure plane ____.

Up

Down

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24. Direct air leakage occurs at:

Windows

Doors

The building shell

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25. Home A has a MVG of 1000. Home B has a MVG of 3000. Indicate which of the following are factors that influence the MVGs in these single family homes.

Climate

Number of occupants

Building height

Shielding o the building from trees

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26. The main goals of air leakage control are to:

Save energy

Increase comfort

Reduce vermin in the house

Enhance fire safety

Avoid moisture migration into building cavities.

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27. Indicate the correct and acceptably way(s) to do a rough test to find the area in the building with the most air leakage during a blower door test.

Close interior doors one by one and measure the pressure difference between the home's main body and the room.

Open and close doors to rooms and note the effect on the blower door airflow.

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28. A fan that blows air into the home moves the neutral pressure plane up because more of the interior space is under positive pressure.

True

False

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29. Which of the following materials are not considered to be air barriers?

Standard concrete block

Spray on cellulose

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30. You are auditing a single family home with four occupants living in it. The blower door flow reading is at 5000 CFM50. Which of the following would be a correct conclusion.

This is the minimum ventilation guideline set by ASHRAE is being met.

Whole house ventilation is recommended.

Carefully targeted air sealing should produce some energy savings.

Minimum ventilation guideline set by ASHRAE is not being met.

Thorough air sealing efforts should produce impressive energy savings.

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