HERS Questions

What is the delivered efficiency of a heating system that has efficiency of .80 and distribution efficiency of .88

.70

1 Therm of natural gas equals approximately how many cubic feet of natural gas?

100

For about the same light output (lumens) a 60W incandescent light bulb would likely be replaced by a CFL using approximately __ W?

15 Watts *Incandescent/4=CFC* *Incandescent/6=LED*

What is the standard pressure at which duct leakage test are conducted?

25 Pa

Thermal Bridge

A thermal bridge, also called a cold bridge, heat bridge, or thermal bypass, is an area or component of an object which has higher thermal conductivity than the surrounding materials, creating a path of least resistance for heat transfer.

A 79% furnace with an input capacity of 80,000 Btuh will have an output capacity of:

A) 63,200 Btuh B) 143,200 Btuh C) 1,013 Btuh D) 79,000 Btuh A

Accepting the defaults for appliance efficiencies will always have which of the following effects?

A) The HERS index will increase B) The HERS index will decrease C) The HERS index will not change D) The HERS index will vary based on the other rated features C

Why are there differences between the modeled seasonal energy load calculations and the actual?

A. Homeowner behavior B. Climatic variation C. Actual installation of insulation/ building components D. All of the above D

What happens to the effective EER due to over sizing of an AC unit - will the oversized equipment have a higher or lower SEER?

A. Size is independent of efficiency B. Oversized equipment will short cycle and run less efficiently, thus effective EER will decrease C. Bigger is better - the larger equipment will quickly satisfy the load and shut off B

What is ideal location for the duct testing fan?

A. Supply register furthest from the air handler B. Supply register closest to the air handler C. Return register that is somewhat restrictive and furthest from the air handlers D. Return register that is least restrictive and closest to the air handler D

Under summer design conditions in Houston, TX air leakage through building envelope has what effect on cooling load?

Adds sensible and latent loads

Which two conditions must be met to skip the duct leakage test?

All ductwork must be 100% visible and located inside the boundary of the conditioned space

If conducting a total duct leakage test when the air handler is not present, how much of the leakage must be added to the duct leakage numbers?

Answer found on HERS Manual (8-12)

When determining the dimensions of a window for the rating you should measure the

Area of window plus flashing

Which of the following units is commonly used to meter residential natural gas consumption?

CCF - 100 cubic feet *Actually charged by the Therm*

When indicating window dimensions on a sketch, what must you record?

Dimensions to include frame (A22)

Which of the following is the most accurate way to measure the tightness of a duct?

Duct Pressurization Test

If the duct blower was connected to the return, what would be the effect of incorrectly placing the duct pressure probe into the return grill instead of the supply plant or supply grill?

Duct leakage could be underestimated You're measuring the pressure right at the blower

What organization rates new wood stoves for their efficiency?

EPA

A rater must disclose financial interest to RESNET.

False

By definition, the net wall area equals gross wall area minus the window area.

False

Higher thermal mass always means a higher R-value.

False

Making a house tighter will never raise interior moisture levels.

False

Reduced duct leakage can't be included in a projected rating because the house isn't built yet.

False

The design temperature is that temperature equaled or exceeded 99% of the time during the 3 coldest months, January, February and July - August.

False

The vapor retarder in hot-humid climate should be installed on the interior of the wall.

False

To be a confirmed rating, all plans must be drawn to scale.

False

One kWh = 3413 Btu/hr.

False (units)

Which of the following conservation measures will have the greatest impact on reducing the heating load on the house

Going from no insulation to some insulation

How should batt insulation be installed in the framed floor under a conditioned space

In contact with the bottom of the subfloor

Which of the following describes. The portion of a homes cooling load caused by water vapor that must be removed by air conditioner?

Latent

What undesirable impact would most likely be cause by small positive building pressures in very cold climates?

Moisture condensation in building cavities

A house is very tight and ductwork is installed in an unconditioned ended attic. What house pressure would you expect when the air handler has more supply leakage than return leakage?

Negative *Supply leaks suck*

An attic has sprayed foam along the roofline. Would the attic floor be counted as CFA in rem rate?

No

A basement has exposed stud walls and concrete floor and is indirectly conditioned; all walls are insulated with paperless fiberglass batts. Would the floor area be counted as CFA in REMrate

No - Not finished, indirectly conditioned - Conditioned basement means there is supply air

Which rating is typically used to express the efficiency of a central AC system?

SEER

What info will an NFRC label contain?

SHGC, U factor, visible light transmittance

Which of the following is correct regarding skylights when entering into remrate

Skylights are similar entries to windows except their area is subtracted from a ceiling and not a wall and the pitch is needed

What health and safety hazard is most likely to be cause by a small negative building pressure?

Soil gas (radon) entry from crawl space

In an architectural drawing, the front of the house faces southwest. Which direction does the right side face?

Southeast

In summer cooling season what is overall effect on HVAC system of a large return leak in an unconditioned attic

System decreases efficiency

Which of the following has no impact on the effectiveness of installed loose fill atic insulation

Temp difference between conditioned and unconditioned space

In a tight house with dominant return leaks connected to the ouse, what will be the effects on the house when the system is operating?

The house is pressurized

When solar radiation strikes an untreated single pane glazing at 90 degree angle, most of it is:

Transmitted

A 2-1/2 ton capacity AC system has the same capacity as a system with a 30,000 Btu/hr capacity.

True

If a residence shares a common wall, ceiling or floor with another dwelling it is a multi-family dwelling.

True

In a very leaky duct system, using the farthest supply register from the air handler for determining the duct pressure will tend to result in a higher leakage rate than would occur from using a supply trunkline, the supply plenum or a register close to the air handler.

True

In the HERS reference home, the windows are evenly distributed.

True

Some states accept HERS ratings as energy code compliance

True

Window area is measured including the frame width?

True

Your provider can conduct an independent inspection for quality assurance (QA) purposes without your permission as a rater.

True

U(avg) =

U1A1+U2A2+.../total sq. footage

If conducting a duct leakage test when register grills are not present, what steps must you take to account for the assumed leakage?

Visual inspection must be conducted to verify effective sealing of boot to ceiling drywall/floor connections *HERS Manual Appendix A-29, duct testing*

An attic has sprayed foam along the roofline. Would the attic volume be counted as conditioned volume in rem rate?

Yes

Does a radiant barrier receive any credit in the REMrate software?

Yes

On a two story house, would the "band" volume be counted as infiltration volume in REMrate

Yes

A 2x4 exterior stud wall has R-13 batts, OSB sheathing (0.5 R-value) and ½-inch drywall (0.4 R-value). The inside air film has an R-value of 0.68; the outside air film has an R-value of 0.17. The framing factor is 23% wood (77% cavity). A 2x4 stud has an R-value of 4.5. What is the U-factor for this assembly?

a) 0.89 b) 0.095 c) 0.089 d) 0.55 C

A house has dimensions of 28' x 42'. What is the floor area and what is the perimeter?

a) 1176 and 140. b) 5544 and 132. c) 1008 and 140 d) 960 and 128 A

A 14' x 14' room has a vaulted shed roof having a 12:12 pitch. What are the approximate dimensions of the roof?

a) 14 x 24 b) 14 x 20 c) 24 x 20 d) 14 x 14 B

A room's dimensions are 40'x40' with a wall plate height of 7' and a vault height of 12' above the floor. What is the vaulted ceiling area?

a) 1474 square feet b) 1649 square feet c) 1872 square feet d) 2080 square feet B

A set of house floor plans is drawn to a scale of 3/8"=1 foot. A wall measures 6-3/4". What is its length?

a) 15.6 feet b) 6.1 feet c) 18 feet d) 17 feet 6 inches C

A set of house floor plans are drawn to a scale of 1/2"=1 foot. The actual house will be how many times larger than the drawings?

a) 24 times bigger b) 4.8 times bigger c) 12 times bigger d) 4 times bigger A

If 990 square feet of an attic is insulated to R-38 and 10 square feet of the attic is a pull-down stairs insulated to R-1, what is the average R-value for the entire attic?

a) 27 b) .036 c) .27 d) 36 A

What is the volume of a round room that is 12' across and has an 8-foot high flat ceiling.

a) 727 sq ft b) 904 cu ft c) 857 cu ft d) 1107 cu ft B

If a ceiling is 40' x 50' with R-10, the inside temperature is 70 and the outside temp is 30, what is the heat flow?

a) 80,000 Btu/hr b) 800 Btu/hr c) 8,000 Btu/hr d) 36,000 Btu/hr C

Which of the following is the efficiency term for a heat pump in the heating mode?

a) AFUE b) SEER c) HSPF d) COP C

For a house, if the stack effect is the only driving force, the house will leak

a) Above the neutral plane b) At the neutral plane c) Below the neutral plane d) Outside the neutral plane D

Which doesn't affect the HERS rating?

a) Air tightness b) Heating efficiency c) Thermostat setting d) SHGC C

Attic kneewalls must be treated separately because they always:

a) Are smaller b) Have different insulation c) Have different areas d) Have different temp differences D

Which of the following is the most accurate way of measuring duct leakage?

a) Blower door Pressure pan b) Blower Door + duct pressurization blower c) Blower door subtraction method d) Tracer gas B

Which of the following is the designation for electric water heater efficiency:

a) COP b) SEER c) AFUE d) EF D

What is the primary mode of heat transfer through an exterior wall assembly:

a) Conduction b) Convection c) Evaporation d) Radiation A

What is the primary mode of heat transfer that is occurring when frost forms on an outdoor object when the ambient air temperature is just above freezing?

a) Conduction b) Convection c) Radiation d) Evaporation C

Which of the following is generally not a feature of EEMs:

a) Energy savings get added to income b) Energy savings get added to appraised value c) Lower interest rate d) Attainable at no additional down payment C

Attic Kneewall details are most likely found on

a) Floor plans b) Elevations c) Sections d) Specifications C

To determine the orientation of a wall, you should be outside and:

a) Have your back to the wall & read the compass b) Face the wall and read the compass c) Use a divining rod d) Call the builder A

What information can be gained from providing a multi-point blower door test vs. a single point blower door test?

a) Improved accuracy when test pressures fluctuate b) The estimated natural air exchange rate c) The skill of the Blower Door operator d) The estimate cost of the leakage A

During a blower door test if the house pressure is 50 pa and the fan pressure is 20 pa what should you do prior to taking a reading?

a) Lower the house pressure to 20 b) Increase the fan pressure to 50 c) Add a ring for greater accuracy d) Remove a ring for greater accuracy C

HERS index is not a function of which one of these

a) Microwave oven b) Heating a) Cooling b) Water heating A

In a house with predominant supply leaks what is the likely negative health effect?

a) Pollutants drawn indoors b) Depressurization c) Moisture diffusion through foundation walls d) Inadequate makeup air A

If a house built in 1998 has a 2x6 wall on the first floor and 2x4 framing on the second floor, the most likely insulation R-values would be:

a) R-21 in the 1st and R-21 in the 2nd floor walls b) R-26 in the 1st and R-7 in the 2nd floor walls c) R-19 in the 1st and R-13 in the 2nd floor walls d) R-13 in both walls C

A home built in 1978 will likely have the following for exterior wall insulation

a) R-7 b) R-15 c) R-19 d) R-11 D

One not so obvious benefit of energy efficient appliances is that they

a) Save you money b) Can reduce air conditioning costs c) Have stronger warranties d) Are more attractive B

When conducting the Blower Door test which of the following steps should be taken?

a) Seal all supply and return registers b) Seal all combustion air ducts in combustion closets c) Leave outside air duct as is for intermittent ventilation d) Seal dry exhaust vent if dryer is not installed C

Which of the following health and safety features is more likely a concern if the house is under a small negative pressure with respect to outside (<3 Pa)

a) Soil gas (e.g., radon) entry into the home b) Backdrafting of 80% furnace c) Window condensation d) Gas leaks A

Tight ducts are more important for right-sized equipment as compared to oversized equipment because

a) The blower operates a higher percentage of the time b) The oversized equipment has a worse warranty c) The oversized equipment has a better warranty d) moisture accumulates on the ductwork A

When operating in the winter (or summer), heat pumps may extract (or reject) heat from (to) all of the following except

a) The building's materials b) The ground around the site c) Ambient air d) Water (lakes, swimming pools, etc.) A

What are "ambient" conditions?

a) The conditions inside the home prior to Blower Door testing b) The reference home's default settings c) The conditions inside attached unconditioned spaces d) The conditions outside of the home D

If a house has a duct system and air handler in an unconditioned attic and there is 100 cfm of return leakage and 200 cfm of supply leakage, how would the house pressure be affected when the air handler is operating?

a) The house goes positive b) The house pressure is not affected c) The house pressure goes negative d) Not enough information is available C

Why would a house's pressure go negative when the air handler is running?

a) There are predominately return leaks b) There are predominately supply leaks c) The duct system is perfectly sealed d) The duct system is completely within the building envelope B

Which feature(s) reduces heat flow through a metal-framed window:

a) Thermal break b) Argon gas filled c) Low-e coating d) All of the above D

Comparing the theoretical reference home vs. a rated home, which is true:

a) They are different shape and size b) They are located in different geographic locations c) They use different fuel types d) They have different amounts of air leakage D

In new homes, where are the leak paths generally the least:

a) Walls b) Floors over vented crawlspaces c) Ceilings A

Which of the following is an example of convection:

a) Warm air moving into attic from house b) Diffusion and perm rating c) Sunlight through a window d) Condensation on iced tea glass A

Comfort is a function of

a) air temperature b) relative humidity c) mean radiant temperature d) all of the above D

Without changing the moisture content, heating the air will cause the relative humidity to

a) increase b) stay the same c) decrease d) cause condensation C

What is a unit commonly used to compare fuels such as oil, gas and LP?

a) mpg b) MMBtu c) gallons d) kWh B

When blower door testing a home with a basement

a) the basement door should be closed when insulation is on the basement ceiling and there is no space conditioning for the basement b) the door is open when insulation is on the basement walls and no insulation is on the ceiling c) the door is open when uninsulated ducts are in the basement, the furnace is in the basement and there is no insulation on basement walls or ceiling d) all of the above D

Regarding windows, good elevation sketches show

a) window locations b) window areas c) overhangs d) all of the above D

HDD is used to:

calc. amount of energy required to heat a house over a heating season