Residential Energy Audit - Chapter 8

Absorbed summer sunlight raises wall & ceiling temperatures, making these surfaces radiant heaters.

• True

• False

Air conditioners must remove moisture from the air to improve indoor comfort.

• True

• False

Solar energy falling on the roof coming trough the windows  account for most of a house's solar heat gain.

• True

• False

Studies by Lawrence Berkley Laboratory estimates that planting trees is ten times more cost effective than building new power plants for summer cooling.

• True

• False

Evaporative coolers work well in regions where the relative humidity remains at less than ___%

• 10

• 50

• 100

SEER apply to

• Central air conditioners

• Room air conditioners

Dueling managers - residents who move the thermostat to suit their different demands - also cause the air conditioning system to operate inefficiently.

• True

• False

Split system air conditioner are charge in the field. Often they will have too much or too little refrigerant.

• True

• False

Relative humidity is the percent at which air at any temperature is ___________ with water vapor.

There are four types of heat gain in a home: - ______________ - internal heat gain - air leakage heat gain - temperature driven heat transmission

Energy conservation measures that block the sun before it strikes the roof or windows are the most effective.

• True

• False

Southern exposure needs __________ trees to block the sun from the south during the summer.

• Shorter

• Taller

• No

Window sunscreen fabric absorbs ___% to ___% of solar heat before it enters the home.

• 15 to 20

• 65 to 70

• 95 to 100

Window sunscreen must be installed on the __________ of the window to be effective.

• Interior

• Exterior

Window sunscreen must be installed on the exterior of the window to be effective and therefor are not practical for outwardly opening windows such as awning or casement windows, unless attached to  movable sash.

• True

• False

Exterior shutters and shades are commonly more expensive that other method used to block the sun entering the window.

• True

• False

What does SHGC stand for?

• Solar heat gain calculation

• Solar heat gain coefficient

• Solar high gain cost

Powerful whole house fans can create strong house pressures that can cause backdrafting or flame roll out in water heaters. To prevent this one should

• Provide adequate window openings

• Keep all windows and doors tightly sealed.

Room air conditioner performance deteriorates as it accumulates dirt.

• True. The air conditioner will eventually breakdown or fail to cool the room.

• False. Room air conditioners have a build self cleaning system that eliminate the need for frequent maintenance.

Oversized air conditioning systems waste energy because they cycle more frequently than correctly sized units.

• True. With each cycle the condenser has to be heated, the evaporated cooled and the duct work cooled before the house begins to be cooled.

• False. Frequent cycle times saves energy because more off cycles means more time where the air conditioning unit is not drawing power to cool the house.

Fiber glass duct liners installed inside metal ducts never deteriorate.

• True. Modern fiberglass material resist deterioration very effectively, and therefor eliminate the possibility of obstruction.

• False. Deterioration happens because of moisture and vibration and may partially block duct airway.

Efficient appliances produce less waste heat.

• True

• False

Trees and plants that provide shade is the best long term investment for reducing cooling costs

• True

• False

Older types of metalized film do have the disadvantage of blocking out daylight in addition to solar heat.

• True

• False

Replacement windows are a cost effective measure for reducing cooling costs.

• True

• False

Visible transmittance measures how much light passes through the window glass.

• True

• False

The best controls for evaporative coolers are reprogrammable thermostats specifically designed for evaporative coolers.

• True

• False

The energy ratings of air conditioners are based on how many BTUs per hour the unit can remove of each watt of power it draws.

• True

• False

Relative humidity below 40% discourage biological pests linked to respiratory problems.

• True

• False

Thermostats often do not provide good comfort control in humid climates.

• Manufactures have developed controls that respond to both temperature and humidity.

• A shortcoming of all air conditioning units are that it is impossible to control humidity and temperature separately.

__________ temperature  accounts for the heat carried by the air's humidity.

• Dry Bulb

• Wet Bulb

Window glass with low solar heat gain coefficient (SHGC) will reduce cooling load, but heating efficient is improved by windows with a low U-factor.

• True

• False

___________ & ____________ determine the rate that a human body can loose heat.

• Shading & windows

• Air temperature & radiant temperature

• Air conditioning systems and window size

____________ is the temperature at which condensation begins.

• Relative humidity

• Minimum temperature

• Dew point

Trees and shrubs create a micro climate, increasing the shaded area's temperature.

• True

• False

Tinted film is as effective as metalized film.

• True

• False

Internal heat gain can be limited by:- limiting the use of hot water- using exhaust fans to remove moisture- reducing coking during the heat of the day

• True

• False

The most cost effective strategies for improving cooling efficiency are different from the strategies to improve heating efficiency. For example   Shade trees will reduce the need for air conditioning but will not reduce the need for heating consumption.

• True

• False

Maintenance and service of air conditioning system to maximize efficiency includes:

• Clean or replace filters

• Clean supply & return registers

• Clean blower fan blades

• Clean evaporator coils

• Clean condenser coils

Circulating air inside your home will:

• Make you feel cooler

• Increases evaporation of sweat

• Carries heat away from your skin

• Have no significant effect on your comfort level

Internal heat gains refer to

• Heat gain from the sun's rays coming through a window

• Heat gain from the heated ceilings and walls

• Heat gains from lightning, refrigeration, water heating, other appliances and the body of heat from the people inside the house.

Air leakage contribute to about 20% of summer heat gain.

• True

• False

Replacing an air conditioner rated at SEER 6 with one that is rated SEER 12 will

• Cut your cooling cost in half

• Double your cooling costs

1 Ton of cooling = ____________ BTUs/H

• 10 000

• 11 000

• 12 000

• 14 200

Superheat and subcooling must generally be done during the heating season.

• True

• False

Ventilation works well when the relative humidity  is up to _____%.

• 100%

• 90%

• 80%

• 70%

• 10%

Awnings on the south side need a drop measurement of ___% to ___% of  the window height to block solar radiation from high in the sky.

• 15 to 20

• 45 to 60

• 85 to 100

Low humidity helps reduce cooling energy consumption, but not heating consumption.

• True

• False