22 Energy Modeling & Baseload Practice Questions & Answers

1. 1. A homeowner asks why an energy model is needed when twelve months of utility bills already show what the house consumes. Which statement best describes what the model is for?

   • A.It documents realized savings after installation, replacing any need for post-work billing analysis.
   • B.It estimates future use and what a measure package would save, so a scope can be justified.✓ Answer
   • C.It reproduces next year's bills exactly, so the homeowner can be promised a guaranteed dollar amount.
   • D.It measures installed equipment efficiency directly, so manufacturer ratings need not be relied upon.

   A model is a predictive tool: it represents the enclosure, the equipment and the climate so that alternative measure packages can be compared and their savings estimated, which is what justifies a scope of work. It is not a meter, not a guarantee, and not a substitute for analyzing bills after the work.

   Source: ANSI/BPI-1100-T-2023 §5 Cost-Benefit Analysis; BA-P Scheme Handbook Domain 2 Task 1 (purpose of modeling)Report a problem with this question

2. 2. A model of an occupied house predicts annual heating gas use about 40 percent below the twelve months of billed gas consumption. What does this most likely mean, and what is the first step?

   • A.The gap is expected: models normally run low, so the output may be reported without further review.
   • B.Inputs are suspect: re-check floor area, enclosure values, leakage and setpoints before reporting.✓ Answer
   • C.Occupants are the cause: report modeled use and note that the family heats above the assumed setpoint.
   • D.Billing is suspect: ask the utility to re-read the meter and treat modeled use as the true baseline.

   Calibration means adjusting the model until modeled consumption reasonably agrees with metered consumption. A gap of this size almost always signals an input error — conditioned area or volume, assembly values, air leakage, equipment efficiency or assumed setpoints — because the bills are a record of what actually happened. Occupant behaviour may explain part of a residual difference, but only after the physical inputs have been verified.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (calibrate the computer model based on utility bill analysis)Report a problem with this question

3. 3. Four data-entry errors are discovered in a completed model of a 2,000 sq ft house. Which one will distort the predicted heating and cooling energy the most?

   • A.One bedroom window entered as double-hung when the installed unit is a casement.
   • B.The domestic water heater set point entered two degrees below the measured setting.
   • C.Conditioned floor area entered as 1,200 sq ft rather than the measured 2,000 sq ft.✓ Answer
   • D.The kitchen refrigerator entered as ten years old when its data plate reads eight.

   Conditioned floor area and volume scale nearly everything downstream: enclosure areas, infiltration volume, internal gains and equipment run time all follow from them. A 40 percent area error therefore moves the heating and cooling results by a large fraction, while a window operator type, a small water-heater setpoint difference or a two-year appliance age change the result only marginally.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (determine pertinent modeling data; recognize potential errors on completed model)Report a problem with this question

4. 4. For the same house with no work done, this winter's billed gas use is 12 percent lower than last winter's, and heating degree days for the period were 15 percent lower. What does this comparison support?

   • A.Total savings were 27 percent; the fuel reduction and the degree-day reduction are added.
   • B.The furnace is failing; a fuel drop smaller than the degree-day drop shows a worn burner.
   • C.Weather alone can account for the drop; normalise by degree days before crediting any change.✓ Answer
   • D.Performance improved by 12 percent; degree days describe outdoor conditions and stay out.

   Heating fuel use scales roughly with heating degree days, so a season 15 percent milder would by itself be expected to cut use by about 15 percent. A 12 percent drop is therefore consistent with weather alone, which is exactly why consumption must be normalised per degree day before two periods are compared. Percentages of fuel and of degree days are never added together.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (utility bill analysis and weather normalization)Report a problem with this question

5. 5. A model shows air sealing with attic insulation saving 180 therms a year and a furnace replacement alone saving 120 therms a year. Modeled together as one package the total is 260 therms, not 300. Why?

   • A.The envelope work lowers the load the new furnace serves, so its share of the savings shrinks.✓ Answer
   • B.Insulation savings are booked as baseload, so they cannot be added to any heating-side saving.
   • C.The furnace's rated efficiency drops once the house is tightened, because it cycles more often.
   • D.The software applies a fixed accuracy discount whenever measures are bundled into one package.

   This is the interactive effect. Savings from a measure are the energy it removes from the load that remains after every other measure, so once the enclosure has cut the heating load, the fuel a more efficient furnace can still save is smaller. Measure savings are therefore modeled as a package rather than added one by one.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (analyze the output from the software; interactive effects between measures)Report a problem with this question

6. 6. A house needs extensive air sealing and attic insulation, and its furnace has failed and must be replaced. What modeling sequence gives correct equipment sizing and correct savings?

   • A.Model the enclosure measures first, then size and credit the furnace against the reduced load.✓ Answer
   • B.Size the furnace to the present load first, then model the enclosure measures against it.
   • C.Model each measure alone at full value and add the two savings to get the package total.
   • D.Match the new furnace to the old unit's capacity, then model the enclosure work afterwards.

   Enclosure measures change the load the equipment must meet, so the load calculation that drives capacity has to reflect the house as it will exist after the work. Sizing to the pre-retrofit load leaves the new unit oversized, which brings short cycling and poor comfort, and crediting both measures at full value double counts the same therms.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (use modeling to determine heating and cooling loads; interactive effects)Report a problem with this question

7. 7. Twelve months after a deep retrofit, metered gas savings are 60 percent of the modeled prediction, and the occupants report that the back bedrooms are finally warm all winter. What best explains the shortfall?

   • A.The weather file was wrong; predictions and bills can differ only through weather data.
   • B.Savings are delayed; retrofit savings always appear one full billing year later.
   • C.Installed measures failed; a shortfall this large can only come from defective work.
   • D.Part of the predicted saving was taken as added comfort instead of reduced fuel — takeback.✓ Answer

   A model predicts savings at fixed assumed setpoints and occupancy. When a previously cold house becomes able to hold temperature, occupants commonly consume part of the improvement as comfort rather than as reduced fuel, which is why a modeled estimate is a prediction and not a promise of realized savings.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (analyze the output; savings sensitivity to occupancy and behaviour)Report a problem with this question

8. 8. A cost and savings report gives modeled annual savings but never states the thermostat setpoints, occupancy or hot-water use that were assumed. Why is that a defect in the report?

   • A.Without listed assumptions the software cannot compute loads and the savings fields stay blank.
   • B.Assumptions need listing only when the output is used to size heating and cooling equipment.
   • C.The estimate depends on those values, and a reader cannot judge or reproduce it without them.✓ Answer
   • D.Setpoints must always be measured rather than assumed before any modeling work may begin.

   Modeled savings are conditional on the assumptions behind them, so an estimate presented without its assumptions cannot be checked, compared with another proposal, or reproduced by a reviewer. Documenting setpoints, occupancy, hot-water use and any other assumed input is what makes the number defensible.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (produce a cost and savings report); ANSI/BPI-1100-T-2023 §5Report a problem with this question

9. 9. Two nearly identical houses on one street receive the same measure package. A year later one shows savings close to the model and the other about half. What most likely accounts for the difference?

   • A.Occupant behaviour differs: setpoints, hours at home, hot-water use and plug loads are not equal.✓ Answer
   • B.Modeling output is random, so repeated runs of one house give substantially different results.
   • C.One crew installed a different brand of material, and brand governs the size of the savings.
   • D.One model used the wrong climate data, since houses on one street cannot otherwise differ.

   A model computes savings for an assumed pattern of use, but realized savings depend on what the occupants actually do: how warm they keep the house, how many hours it is occupied, how much hot water they draw, and what equipment they leave running. Identical buildings with different households routinely realise different savings.

   Source: BA-P Scheme Handbook Domain 2 Task 1 (savings estimates sensitive to occupancy and behaviour)Report a problem with this question

10. 10. A completed model reports large annual dollar savings for one measure while the energy savings in therms and kWh are small. Which input should be checked first?

    • A.The conditioned volume, which changes the dollar result but never the energy quantities.
    • B.The measure's expected life, which changes annual dollars but never annual energy units.
    • C.The fuel type or energy price assigned to that end use, which can inflate the dollar result.✓ Answer
    • D.The infiltration rate, which drives cost outputs only and leaves energy outputs untouched.

    Dollar savings in a model are energy savings multiplied by an assumed price for the fuel serving that end use. When money and energy move by very different amounts, the price or the fuel assignment is the input doing the work, and it is checked first. Volume and infiltration change energy and dollars together, not one alone.

    Source: BA-P Scheme Handbook Domain 2 Task 1 (recognize potential errors on completed model; resources available for pricing)Report a problem with this question

11. 11. An analyst intends to use model output to select the capacity of a replacement boiler in a house that will also be air sealed and insulated. What makes that output suitable for equipment selection?

    • A.The load is taken from the existing boiler's input rating with a generous margin added for safety.
    • B.The load is set from floor area by a rule of thumb that is accepted in most climates.
    • C.The load is computed from the post-retrofit enclosure at the design conditions for that location.✓ Answer
    • D.The load is derived from the highest billed month of fuel divided by the heating hours.

    Capacity must answer the load the building will actually impose, so the model has to describe the enclosure as it will exist after the retrofit and evaluate it at the local design temperature. Sizing from the old unit's rating, from a peak bill or from a per-square-foot rule perpetuates oversizing, which produces short cycling and uneven comfort.

    Source: BA-P Scheme Handbook Domain 2 Task 1 (use modeling software to determine heating and cooling loads)Report a problem with this question

12. 12. An audit report states 'estimated annual savings: 22 percent.' Under the home energy auditing standard, what must accompany that figure for it to be meaningful?

    • A.A statement of whether simulation software or a manual worksheet produced the number.
    • B.A statement of whether the installing contractor guarantees the saving under contract.
    • C.A statement of whether the saving is for baseload, heating, cooling, or total consumption.✓ Answer
    • D.A statement of whether a program administrator reviewed the figure before issuance.

    A bare percentage is ambiguous: 22 percent of the heating fuel, of the baseload, or of everything the household uses are very different promises. The auditing standard therefore requires savings estimates to state plainly which portion of consumption they apply to, so the homeowner can compare offers on the same basis.

    Source: ANSI/BPI-1100-T-2023 §5.3 (savings estimates shall indicate baseload, heating, cooling, or total consumption)Report a problem with this question

13. 13. An auditor who does not own simulation software asks whether a cost-benefit analysis can still be produced for the audit report. Under the home energy auditing standard, which is correct?

    • A.It cannot: hand methods are allowed for baseload alone, never for heating and cooling savings.
    • B.It can, but only where the authority having jurisdiction has waived the modeling requirement.
    • C.It cannot: a simulation model is the only acceptable basis for any projected savings figure.
    • D.It can: savings may be shown as reduced fuel, reduced cost, or an improvement on a benchmark.✓ Answer

    The auditing standard requires a cost-benefit analysis but treats simulation software as an option rather than a requirement, and it allows the benefit to be expressed as reduced fuel use, reduced energy cost, a fractional performance improvement, or a score on a recognised benchmark. The obligation is to present a defensible analysis, not to use a particular tool.

    Source: ANSI/BPI-1100-T-2023 §5.2 (Note: energy simulation software is an option, but not a requirement)Report a problem with this question

14. 14. Which group of end uses is correctly classified as baseload energy use in a home energy audit?

    • A.All consumption billed in the three coldest months once the heating fuel is subtracted.
    • B.Lighting, kitchen and cleaning appliances, water heating, and constantly running electronics.✓ Answer
    • C.Space heating, space cooling, and the fans and pumps that distribute conditioned air.
    • D.Every end use served by electricity, since fuel-fired equipment is weather dependent.

    Baseload is defined by its independence from outdoor temperature, not by fuel type or by season. It covers the devices that run much the same all year — lighting, kitchen and cleaning appliances, domestic water heating and electronics in frequent or constant use — while space heating and cooling are the weather-dependent portion separated from it.

    Source: ANSI/BPI-1100-T-2023 Annex A, definition of Baseload Energy UseReport a problem with this question

15. 15. Twelve consecutive monthly gas bills are available and the three lowest months are 11, 12 and 13 therms. The manual method computes annual gas baseload as 12 x 1.1 x (average of the three lowest months). What is the annual gas baseload?

    • A.About 174 therms per year.
    • B.About 158 therms per year.✓ Answer
    • C.About 144 therms per year.
    • D.About 132 therms per year.

    The average of 11, 12 and 13 therms is 12 therms per month. Multiplying by twelve months gives 144 therms, and the 1.1 factor that accounts for the small amount of weather-driven use still present in the mildest months brings the result to 158.4 therms per year. Omitting the 1.1 factor produces the 144 therm answer.

    Source: ANSI/BPI-1200-S-2017 §12.4.2.1.1 (annual gas baseload = 12 x 1.1 x average of three lowest months)Report a problem with this question

16. 16. A home has an electric heat pump with the thermostat in automatic heat/cool changeover and a pool that runs year round in a mild climate. What is the effect on the three-lowest-months baseload method?

    • A.It has no effect, since the method already strips all weather-dependent use from the bills.
    • B.It is not permitted for electricity, since the method applies only to metered natural gas.
    • C.It can underestimate baseload, since the pool pump is switched off in the three mildest months.
    • D.It can overestimate baseload, since heating, cooling or pool use may occur in every month.✓ Answer

    The three-lowest-months method assumes the mildest months contain no space conditioning. An automatic changeover thermostat can call for heat on cool mornings and cooling on warm afternoons within the same month, and a year-round pool adds load in every month, so weather-driven and seasonal use leaks into the months chosen as the base and inflates the result.

    Source: ANSI/BPI-1200-S-2017 §12.4.2.1.2, Note (automatic changeover and year-round pool operation)Report a problem with this question

17. 17. A 1,400 sq ft home with two occupants shows an electric baseload roughly three times what is typical for its size, while heating and cooling use look ordinary. What should the analyst investigate first?

    • A.An undersized heat pump running long hours, which raises consumption in every month alike.
    • B.A leaking attic duct, which adds a constant load that does not depend on outdoor temperature.
    • C.A misread gas meter, since baseload anomalies arise in the fuel not used for space heating.
    • D.A large always-on load such as a second refrigerator, a well pump, or a recirculation pump.✓ Answer

    Because baseload is the portion of consumption independent of outdoor temperature, a baseload far above the norm while heating and cooling look normal points to something drawing power continuously all year. A garage refrigerator, a short-cycling well or sump pump and an uncontrolled hot-water recirculation pump are the classic culprits, and each is found by inspection rather than by remodeling.

    Source: ANSI/BPI-1100-T-2023 §12 Baseload Energy Efficiency; ANSI/BPI-1200-S-2017 §12.1-12.3Report a problem with this question

18. 18. The analyst has established the home's total annual baseload from the utility history. Why go on to disaggregate that baseload by individual end use?

    • A.To identify which devices carry the load so measures can target the largest consumers.✓ Answer
    • B.To satisfy a requirement that each device be metered individually with a plug meter.
    • C.To confirm the heating and cooling split, which no other analysis method can provide.
    • D.To convert electric baseload into therms so every fuel appears on one report line.

    A single baseload total says how much is used but not by what, so it cannot be turned into recommendations. Breaking it into water heating, refrigeration, lighting, laundry, pool and plug loads shows where the energy actually goes and lets the work scope address the few end uses that dominate rather than every device in the house.

    Source: BA-P Scheme Handbook Domain 1 Task 8 (disaggregate baseload energy use)Report a problem with this question

19. 19. An electric utility history shows a flat baseload for two years, then a step increase of roughly 90 kWh a month beginning in March and persisting through the following winter, with heating and cooling patterns unchanged. What does this point to?

    • A.An unusually cold March, because weather is what produces a step change lasting a full year.
    • B.A change in the utility's rate design, because rates alter the kilowatt-hours the meter logs.
    • C.A failing air conditioner, because a step rise beginning in spring is always cooling related.
    • D.A device or setting added in March that runs continuously, since the rise ignores season.✓ Answer

    A change that appears at one point and then holds through every season is by definition not weather driven, so it belongs to baseload rather than to heating or cooling. The interview should look for what entered the house or changed in it that month: a freezer, a dehumidifier left running, a well pump, a hot tub, or a recirculation pump switched to continuous operation.

    Source: BA-P Scheme Handbook Domain 1 Task 8 (determine heating, cooling and baseloads through utility bill analysis)Report a problem with this question

20. 20. A house has a domestic hot-water recirculation pump wired to run continuously. What is the energy consequence, and what should the analyst recommend?

    • A.Standby losses run all day; control the pump by demand or schedule and insulate the loop.✓ Answer
    • B.Losses occur only during draws; continuous running saves energy by shortening each wait.
    • C.The losses are on the cold side; insulating the cold supply lines is the useful correction.
    • D.Only electric use rises; the water heater's fuel consumption is unaffected by circulation.

    A continuously circulating loop keeps the whole run of piping hot every hour of the year, so heat is lost to the surrounding space around the clock and the water heater fires to replace it, on top of the pump's own electric draw. Putting the pump on demand or timer control and insulating the loop removes most of that standby loss.

    Source: ANSI/BPI-1200-S-2017 §11.12.6 (hot water pipe insulation); BA-P Scheme Handbook Domain 1 Task 7 (DHW distribution and controls)Report a problem with this question

21. 21. A 2.5 gpm shower head is replaced with a 1.75 gpm model and nothing else changes. By what mechanism does this save energy, and which part of consumption does the saving fall in?

    • A.Pressure at the fixture increases, so the pump and the heater each run at higher efficiency.
    • B.Less hot water is drawn per shower, so the water heater burns less fuel — a baseload saving.✓ Answer
    • C.Shower length shortens by itself, so the saving is credited to the space-heating end use.
    • D.Delivered temperature rises at the head, so the tank setpoint can be lowered to compensate.

    A water measure becomes an energy measure through the volume of heated water it avoids: fewer gallons per minute at the same temperature and the same shower length means fewer gallons the heater must raise from mains temperature. Because domestic water heating is part of baseload, the saving belongs there and not to space heating.

    Source: ANSI/BPI-1200-S-2017 §13.1 (shower heads and low-flow devices); ANSI/BPI-1100-T-2023 Annex A (baseload includes domestic water heaters)Report a problem with this question

22. 22. During the water conservation portion of a whole-home assessment, which set of observations does the standard call for the auditor to record?

    • A.Distance from heater to each fixture, the loop volume, and the measured wait time at every tap.
    • B.Static pressure at the water main, the pipe material and its diameter, and the heater's recovery rate.
    • C.Quantity and type of shower heads, toilets and faucets, aerators, and any fixture or flapper leakage.✓ Answer
    • D.The municipal water rate, the household's billed gallons, and the cost of each fixture swap.

    The water conservation assessment is an inventory of fixtures and of leaks: how many shower heads, toilets and faucets there are, what type each is, whether they are low-flow or fitted with aerators or water-conserving designs, and whether any fixture or toilet flapper valve is leaking. Pressures, pipe sizing and pricing belong to other parts of the assessment.

    Source: ANSI/BPI-1200-S-2017 §13.1 (record quantity and type of shower heads, toilets, faucets; note leaks and flapper valve leakage)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 →