22 Heating, Cooling & Distribution Practice Questions & Answers

1. 1. An auditor's data sheet shows a gas furnace whose nameplate lists a temperature rise range of 40-70 F. The measured supply-minus-return temperature rise is 85 F and the filter is clean. What is the appropriate analysis and recommendation?

   • A.The rise is above the listed range but harmless, so record the value and recommend only that the filter be changed.
   • B.The rise indicates excess airflow, so recommend that the blower speed be lowered until the value falls back in range.
   • C.The rise is above the listed range, so recommend the unit and its duct system be evaluated by a qualified professional.✓ Answer
   • D.The rise is normal for gas equipment, so recommend the nameplate range be disregarded during the heating season.

   Temperature rise is the heat the air picks up crossing the heat exchanger, so a rise above the manufacturer's listed range means too little air is moving for the fired input: restricted or undersized ducts, closed dampers, a weak blower, or an overfired burner. Because the cause may lie in either the appliance or the distribution system, the auditor documents the finding and recommends that both be evaluated by a qualified professional rather than adjusting the equipment personally.

   Source: ANSI/BPI-1200-S-2017 Section 11 (heating appliance evaluation; measured temperature rise compared with the nameplate listed range)Report a problem with this question

2. 2. A combustion analyzer reports a steady-state efficiency of 81% on an atmospheric gas furnace whose nameplate seasonal rating (AFUE) is 78%. How should the auditor interpret the two numbers?

   • A.Steady-state efficiency replaces the seasonal rating once the appliance has been in service for more than two heating seasons.
   • B.Steady-state efficiency is a laboratory rating, while the seasonal rating is the field value measured with the burner stabilized.
   • C.Steady-state efficiency and the seasonal rating measure the same quantity, so the higher of the two figures belongs in the model.
   • D.Steady-state efficiency describes the burner at stable operation; the seasonal rating also includes cycling and off-cycle losses.✓ Answer

   A steady-state measurement is taken after the burner has stabilized and describes only how completely fuel is converted at that moment. A seasonal rating is a laboratory-derived annual figure that also accounts for start-up losses, jacket losses and off-cycle flue losses over many cycles, which is why it is normally lower than a steady-state reading on the same appliance.

   Source: BPI Building Science Principles Reference Guide — steady-state combustion efficiency versus seasonal (AFUE) ratingReport a problem with this question

3. 3. Collected data show a furnace whose fired input is far above the calculated design heating load of the house. What consequence should the auditor expect and report?

   • A.Longer burner cycles that hold the heat exchanger above its design temperature and raise flue losses steadily.
   • B.Reduced distribution losses, because the larger blower forces air past the duct leaks more quickly on each cycle.
   • C.Steadier room temperatures with lower fuel use, since a larger burner satisfies the thermostat sooner each cycle.
   • D.Short burner cycles that keep the unit in its least efficient warm-up phase and swing room temperatures noticeably.✓ Answer

   An appliance sized well above the load satisfies the thermostat quickly and shuts off, so it spends a large fraction of its running time warming up the heat exchanger and ductwork rather than delivering heat at stable efficiency. The repeated purge and warm-up cycles waste fuel, and the fast on-off pattern produces temperature swings and uneven room-to-room delivery.

   Source: ANSI/BPI-1100-T Section 11 (equipment evaluation) with ACCA Manual J/S load-based sizing principleReport a problem with this question

4. 4. Occupants report that the house feels cool but clammy in summer, and the collected data note that the cooling system satisfies the thermostat in very short runs. Which analysis fits the data?

   • A.The system is oversized for the load, so short run times remove sensible heat without enough coil runtime to remove moisture.✓ Answer
   • B.The refrigerant charge is high, so the coil runs warm and removes latent heat faster than it removes sensible heat.
   • C.The system is undersized for the load, so long run times overcool the air before the coil can condense moisture from it.
   • D.The thermostat setpoint is too low, so the system removes moisture faster than it removes sensible heat from the rooms.

   Sensible cooling drops air temperature and happens almost immediately, while latent cooling requires the coil surface to stay below the dew point long enough for water vapor to condense and drain away. An oversized system reaches the thermostat setpoint before that dehumidification work is done, so the space ends up cool but with high relative humidity.

   Source: BPI Building Science Principles Reference Guide — sensible versus latent cooling capacity; ACCA Manual J load componentsReport a problem with this question

5. 5. In a split air conditioner operating normally in cooling mode, what happens at the indoor evaporator coil?

   • A.High-pressure refrigerant vapor condenses and releases heat into the air passing over the coil.
   • B.Expanding refrigerant is pressurized there and carries heat from outdoors into the indoor air.
   • C.Compressed refrigerant vapor is cooled there and rejects its heat into the indoor air stream.
   • D.Low-pressure liquid refrigerant boils and absorbs heat from the air passing over the coil.✓ Answer

   In the vapor-compression cycle the metering device drops refrigerant pressure so it boils at a temperature below that of the indoor air. Heat flows from the warmer air into the colder refrigerant as it changes state, which is why the evaporator both cools the air and condenses moisture out of it; the heat is later rejected outdoors at the condenser.

   Source: Building science fundamentals of heat transfer — vapor-compression refrigeration cycle (evaporator, compressor, condenser, metering device)Report a problem with this question

6. 6. The design heating load of a house rises as outdoor temperature falls. Over that same temperature range, how does the output of the air-source heat pump serving it behave?

   • A.Its heating capacity rises as outdoor temperature falls, so output exceeds the load throughout the heating season.
   • B.Its heating capacity drops only once the defrost control engages, so output matches the load right up to then.
   • C.Its heating capacity falls as outdoor temperature falls, so output and load converge at the balance point.✓ Answer
   • D.Its heating capacity stays fixed at the nameplate rating, so any shortfall comes only from duct leakage losses.

   An air-source heat pump extracts heat from outdoor air, so as that air gets colder there is less heat available and the refrigerant density entering the compressor drops, reducing delivered capacity. The load is rising at the same time, and the outdoor temperature where the two curves cross is the balance point; below it the system needs supplementary heat.

   Source: BPI Building Science Principles Reference Guide — air-source heat pump capacity versus outdoor temperature and the balance pointReport a problem with this question

7. 7. A homeowner says they switch the thermostat to Emergency Heat every winter night because the house warms up faster that way. What should the auditor tell them?

   • A.Emergency heat locks out the compressor and heats with resistance elements alone, which sharply raises operating cost.✓ Answer
   • B.Emergency heat runs the compressor at full output with the elements locked out, which lowers the operating cost.
   • C.Emergency heat only changes the blower speed, so the setting has no measurable effect on winter operating cost.
   • D.Emergency heat is the normal winter setting for a heat pump and should be used whenever it is below freezing.

   Emergency heat is a manual mode intended for when the compressor has failed: it disables the heat pump and heats entirely with electric resistance elements. Because resistance heat delivers only the heat equivalent of the electricity it draws while a working compressor moves several times that much, running in emergency heat by choice discards the heat pump's advantage every night.

   Source: BPI Building Science Principles Reference Guide — heat pump controls: supplementary heat versus emergency heatReport a problem with this question

8. 8. An auditor observes that an air-source heat pump periodically stops heating, shuts off the outdoor fan, and steams off the outdoor coil. What is happening?

   • A.The unit is losing charge, so the outdoor coil frosts and the control shuts the compressor down to protect it.
   • B.The unit is in defrost, stopping the compressor so ambient air alone melts the frost off the outdoor coil.
   • C.The unit is in defrost, reversing refrigerant flow to warm the outdoor coil and melt the frost off it.✓ Answer
   • D.The unit is stuck in cooling mode, so the outdoor coil frosts whenever the outdoor air is near freezing.

   In heating mode the outdoor coil runs below ambient temperature, so moisture in the outdoor air condenses and freezes on it. The defrost control periodically switches the reversing valve so hot refrigerant flows to the outdoor coil, stops the outdoor fan so that heat is not blown away, and melts the frost; back-up heat usually runs during this interval to temper the supply air.

   Source: Building science fundamentals — air-source heat pump defrost cycle and reversing valve operationReport a problem with this question

9. 9. Compare a ducted central heat pump with a ductless mini-split serving the same room. Which statement about how each delivers heat is correct?

   • A.The mini-split delivers heat through a short duct run, so its distribution losses match those of the central system.
   • B.The two systems both pipe refrigerant into the room, so neither has any distribution loss worth considering.
   • C.The mini-split delivers heat straight into the room, avoiding the conduction and leakage losses of a duct run.✓ Answer
   • D.The central system delivers heat straight into the room, so its distribution losses are lower than the mini-split's.

   A ductless system pipes refrigerant to a wall or ceiling head inside the conditioned space, so the only losses are at the insulated refrigerant lines. A central system moves the same heat as air through sheet metal or flex duct, which conducts heat through its walls and leaks air at every joint, and those losses grow sharply when the duct run passes through unconditioned space.

   Source: ANSI/BPI-1200-S-2017 Section 11 (heating and cooling distribution evaluation); ductless system distribution-loss principleReport a problem with this question

10. 10. A house heated with electric baseboard is being compared with an air-source heat pump running on the same electricity supply. What accounts for the heat pump using less electricity for the same delivered heat?

    • A.It stores heat in the refrigerant during mild weather and releases it during the coldest hours of the day.
    • B.It moves heat from outdoor air rather than creating it, delivering more heat than the electricity it draws.✓ Answer
    • C.It burns a small amount of fuel to supplement the elements, reducing the electricity registered at the meter.
    • D.It converts electricity into heat more completely than resistance elements do, exceeding full conversion.

    Electric resistance converts essentially all of the electricity it draws into heat, so it can never deliver more heat than the energy it consumes. A heat pump is a transport device: the electricity runs a compressor that moves heat already present in the outdoor air into the house, so delivered heat is a multiple of the electrical input and that ratio falls as outdoor air gets colder.

    Source: Building science fundamentals — coefficient of performance of a heat pump versus electric resistance heatingReport a problem with this question

11. 11. A heat pump water heater has been installed in a small, tightly closed utility closet inside conditioned space. What should the auditor report?

    • A.The closet's size cannot affect performance, so recommend recording the nameplate and taking no further action.
    • B.The closet is an ideal location for this equipment, since its small enclosed volume raises the air temperature.
    • C.The closet may not hold enough air for the unit, so recommend checking the manufacturer's requirements.✓ Answer
    • D.The closet will be warmed by the unit, so recommend a louvered door to release the heat it adds to the space.

    A heat pump water heater extracts heat from the air around it and discharges cooler, drier air back into the room, so it needs a minimum air volume or ducted/louvered air exchange to keep drawing usable heat. Sealed into a small closet the surrounding air chills, capacity collapses and the unit falls back on its resistance elements, so the auditor recommends verifying the manufacturer's installation requirements.

    Source: ANSI/BPI-1200-S-2017 Section 11 (DHW appliance evaluation; installation per manufacturer's instructions)Report a problem with this question

12. 12. A house has a hot water recirculation pump running continuously on an uninsulated copper loop that passes through an unconditioned basement. What is the correct analysis?

    • A.The loop only loses heat when a fixture is opened, so recommend no change to the pump's control strategy.
    • B.The loop's losses are offset by basement heat gain, so recommend removing the basement's other heat source.
    • C.The loop saves energy by keeping water hot, so recommend the pump stay on and the piping remain bare.
    • D.The loop loses heat around the clock, so recommend insulating the piping and adding demand or timer control.✓ Answer

    A continuously circulating loop keeps the whole pipe run at storage temperature every hour of the year, so bare copper in an unconditioned space sheds heat by conduction and convection continuously, not just during draws. Insulating the piping cuts the loss rate and switching to demand or timer control cuts the hours of loss, which is why both measures belong in the recommendation.

    Source: ANSI/BPI-1200-S-2017 Section 11 (DHW distribution: pumps, piping and terminations); DOE, Evaluating Domestic Hot Water Distribution System OptionsReport a problem with this question

13. 13. An auditor records that a storage water heater's temperature control is set considerably higher than the occupants need. Which pair of consequences should the report describe?

    • A.A higher setting raises standby and distribution losses and increases the risk of scalding at the fixtures.✓ Answer
    • B.A higher setting lowers standby losses because the tank cycles less often, and it removes scald risk entirely.
    • C.A higher setting lowers distribution losses because hot water reaches the fixtures faster through the piping.
    • D.A higher setting has no effect on standby losses, and scald risk depends only on the mixing valve at the tank.

    Heat loss from a tank and its piping is driven by the temperature difference between the water and the surrounding air, so raising the setting increases losses continuously whether or not water is drawn. The same higher delivery temperature shortens the time it takes to burn skin at a fixture, which is why the setting is recorded and discussed as an energy and a safety item together.

    Source: ANSI/BPI-1200-S-2017 Section 11 (record the water heater temperature control setting; DHW evaluation)Report a problem with this question

14. 14. While evaluating collected data on a central air conditioner, which set of nameplate values must be present for the equipment analysis to be complete?

    • A.Input and output in BTUh, listed temperature rise, and the appliance's measured steady-state efficiency.
    • B.Compressor amperage, condensate pump rating, filter size, and the required combustion air opening area.
    • C.Rated capacity in BTUh, refrigerant type, efficiency rating, and the maximum allowable external static pressure.✓ Answer
    • D.Rated capacity in BTUh, listed temperature rise, flue gas temperature, and the refrigerant line set length.

    Cooling equipment is documented by the values that let an analyst judge capacity against load and airflow against the system: rated capacity in BTUh, the refrigerant the machine is charged with, its efficiency rating, and the maximum external static pressure the air handler is listed for. Temperature rise, flue gas temperature and combustion air openings belong to combustion heating appliances, not to a compressor-based cooling system.

    Source: ANSI/BPI-1200-S-2017 Section 11 (cooling appliance data: capacity in BTUh, refrigerant type, efficiency, maximum external static pressure)Report a problem with this question

15. 15. The data sheet notes rust staining and an active leak at the base of a 14-year-old gas storage water heater. What should the report recommend?

    • A.Draining and refilling of the tank to flush out the sediment that caused the staining.
    • B.Sealing of the tank seam and reinsulation of the jacket during the weatherization work.
    • C.Monitoring of the leak and reinspection of the tank at the next scheduled audit visit.
    • D.Replacement with a high-efficiency appliance installed by a qualified professional.✓ Answer

    A leak at the base of a steel storage tank means the glass lining and shell have corroded through; that damage cannot be repaired, and the leak will worsen. The evaluation therefore calls for replacement, specified as a high-efficiency appliance and installed by a qualified professional, and it is also a durability issue because the leaking tank can damage finishes and framing.

    Source: ANSI/BPI-1200-S-2017 Section 11 (leaking DHW tank: recommend replacement with high-efficiency equipment by a qualified professional)Report a problem with this question

16. 16. A work scope includes air sealing and attic insulation along with replacement of the existing furnace. How should the replacement furnace be sized?

    • A.From the load calculation that reflects the improved enclosure, not from the existing unit✓ Answer
    • B.From the floor area, using a rule-of-thumb BTUh per square foot figure for the local climate zone.
    • C.From the existing unit's input rating plus a safety factor, so the new unit recovers quickly after a setback.
    • D.From the existing unit's input rating, since the previous installer sized it for this house and climate.

    Equipment must be selected from the heating load the building actually presents, and air sealing and insulation reduce that load, so a load calculation performed on the post-retrofit enclosure is the only valid basis. Replacing in kind or adding a safety factor carries forward the old oversizing, producing short cycles, poor comfort and higher installed cost for capacity the house no longer needs.

    Source: ANSI/BPI-1100-T Section 6 (work scope) with ACCA Manual J/S load-based equipment selectionReport a problem with this question

17. 17. The collected data list a measured total external static pressure well above the maximum shown on the air handler's nameplate, with a clean filter installed. What does this most likely indicate?

    • A.Oversized supply and return ducts, which should be corrected by closing the dampers at the supply registers.
    • B.Leakage at the supply plenum, which lowers pressure at the registers and should be sealed right away.
    • C.Excess airflow through the duct system, which should be corrected by raising the blower speed setting.
    • D.Restriction in the duct system or coil, which lowers airflow and should be evaluated by a professional.✓ Answer

    External static pressure is the resistance the blower has to work against, so a high reading means air is being squeezed through something too small or too dirty: undersized or crushed ducts, too few returns, a restrictive filter rack or a fouled coil. High static pressure lowers delivered airflow, hurts capacity and comfort and shortens blower and compressor life, so the auditor recommends professional evaluation of the distribution system.

    Source: ANSI/BPI-1200-S-2017 Section 11 (record listed maximum external static pressure; evaluate distribution for airflow restrictions)Report a problem with this question

18. 18. Pressure-pan readings and the visual inspection both support recommending duct sealing. What else must the work scope include, and why?

    • A.A post-installation static pressure measurement, because sealing a leaky system can restrict airflow.✓ Answer
    • B.A post-installation filter upgrade, because sealed ducts carry more dust and need a denser filter medium.
    • C.A post-installation flue draft test, because sealing ducts always reduces the draft available to the chimney.
    • D.A post-installation refrigerant charge check, because sealing ducts changes the compressor's suction pressure.

    Leaks act as unintended openings that relieve pressure in the duct system, so closing them makes the blower push the full airflow through the remaining path and total external static pressure rises. If the ducts were already marginal that rise can cut airflow below what the equipment needs, so the scope must call for a post-installation static pressure measurement by a qualified professional to confirm the system still moves the required air.

    Source: ANSI/BPI-1200-S-2017 Section 11 (duct sealing recommendations shall include post-installation total external static pressure measurement)Report a problem with this question

19. 19. Two houses show the same total duct leakage rate. In one the ducts run through a vented crawlspace; in the other they run entirely within conditioned space. Why does the distinction matter?

    • A.Leakage inside conditioned space wastes the same energy, since all leaked air escapes the thermal boundary.
    • B.Leakage to outside removes conditioned air from the house and drives pressure imbalances across the enclosure.✓ Answer
    • C.Leakage to outside is harmless, because the leaked air returns through the crawlspace vents to the return duct.
    • D.Leakage inside conditioned space is the greater loss, because interior air is warmer than crawlspace air.

    Duct leakage matters in proportion to whether the leaked air crosses the pressure and thermal boundary. Supply leakage into a crawlspace dumps paid-for conditioned air outside the boundary and depressurizes the house, pulling in unconditioned replacement air; return leakage pressurizes it. Leakage that stays inside the conditioned space still upsets room-to-room balance but does not directly export the energy, so the two cases are prioritized differently.

    Source: ANSI/BPI-1200-S-2017 Section 11 (duct leakage evaluation; leakage to the outside shall be tested where building cavities serve as ducts)Report a problem with this question

20. 20. In a hot, humid climate an uninsulated metal supply plenum located inside the conditioned thermal boundary is found dripping water during cooling operation. What explains this?

    • A.The plenum is leaking conditioned air, so water is carried out of the duct and onto its outer surface.
    • B.The plenum receives condensate carried off an oversized coil, so water runs out through its sheet metal seams.
    • C.The plenum surface sits below the dew point of the surrounding air, so moisture condenses onto the metal.✓ Answer
    • D.The plenum is warmer than the surrounding air, so room humidity migrates outward through its metal seams.

    Bare sheet metal carrying cold supply air takes on nearly the temperature of that air. When the surrounding air is humid enough that its dew point is above that surface temperature, water vapor touching the metal condenses out, exactly as it does on a cold drink. Insulating the plenum keeps its outer surface above the dew point, which is why cooling ducts are insulated in humid climates even inside the thermal boundary.

    Source: ANSI/BPI-1200-S-2017 Section 11 (insulation of metal cooling ducts and plenums inside the thermal boundary in humid climates)Report a problem with this question

21. 21. With the air handler running and all interior doors closed, bedrooms that have supply registers but no return path read positive relative to the central hallway. What analysis and recommendation follow?

    • A.Closed doors reduce supply airflow to the bedrooms, so the readings show undersized supply ducts; recommend larger registers.
    • B.Closed doors have no effect on system pressures, so the readings indicate a failing blower; recommend replacing the assembly.
    • C.Closed doors improve system balance, so these pressures are expected; recommend that occupants keep the doors closed.
    • D.Closed doors block the return path, so bedrooms are pressurized and the central zone is depressurized; recommend transfer paths.✓ Answer

    A central return can only pull air out of a room that has a way for air to get back to it. When the door closes, supply air keeps entering the bedroom and pressurizes it while the rest of the house goes negative, which increases infiltration, exfiltration and depressurization of the zone containing the return, so transfer grilles, jump ducts or undercut doors are recommended to restore the return path.

    Source: ANSI/BPI-1200-S-2017 Annex D (analyze the distribution system for HVAC-induced pressure imbalances; improve air transfer between zones)Report a problem with this question

22. 22. While evaluating a steam boiler, the occupant states that water has to be added to the system several times each heating season. What should the report state?

    • A.Repeated make-up water indicates a loss somewhere in the system, so recommend service by a qualified professional.✓ Answer
    • B.Repeated make-up water is normal for steam systems, so recommend that the occupant simply continue the practice.
    • C.Repeated make-up water indicates a fouled sight glass, so recommend cleaning it before the next heating season.
    • D.Repeated make-up water indicates an oversized expansion tank, so recommend that the tank be drained each fall.

    A steam system is a closed loop that should hold its water, so needing repeated make-up means water is escaping through a leaking return line, a failing valve, a cracked section or an over-venting condition. Fresh make-up water also brings dissolved oxygen and minerals that accelerate corrosion and scaling, so the auditor documents the report and recommends the system be serviced by a qualified professional.

    Source: ANSI/BPI-1200-S-2017 Section 11 (steam boiler evaluation: sight glass level and whether water was added or removed during the heating season)Report a problem with this question

Practice questions based on the BPI Building Analyst Professional exam blueprint, the ANSI/BPI-1100-T home energy auditing standard, the ANSI/BPI-1200-S standard practice, and building science fundamentals. This site is not affiliated with or endorsed by the Building Performance Institute. Combustion appliance zone depressurisation limits, carbon monoxide action levels, draft pressures, spillage times, ventilation rates and air-change targets come from the version of the standard in force for your certification and from the manufacturer's instructions — never from a practice test. The BA-P requires the Building Analyst Technician certification, which in turn requires the Building Science Principles certificate; confirm current eligibility, prerequisites and exam requirements with BPI before you test. About BPI certification →