School Energy Audit and Depth Study
In 2021, ARENA funded an NSW school energy audit, their findings showed $18,000 in annual savings were possible by fixing 4 simple issues.
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Q1 · Your school's electricity bill is $50,000 per year. Before reading, which parts of a school do you think use the most electricity, and which changes would save the most money?
Q2 · What does an "energy audit" involve? What data would you collect, and how would you turn those measurements into a recommendation for change?
Walk into your school at 6 pm on a Friday, the classrooms are empty but the lights are on, the air-conditioning is humming, and the hot water system is heating water nobody will use until Monday. Each of those costs money and burns energy for zero benefit. A school energy audit is a systematic investigation of where that waste is happening, how large each source of waste is, and what changes would eliminate it, applying the scientific method to a real-world problem with real financial consequences.
The audit begins with identification, walking through the school and listing every energy user from lights to air conditioners to computers. Baseline data from utility bills provides historical context. Direct measurements with plug-in power meters reveal actual consumption patterns. Analysis prioritises the biggest opportunities. Recommendations should be specific, costed, and actionable.
A typical school audit might reveal that hallway lights are left on 24/7, air conditioners run with windows open, and old refrigerators in staff rooms consume three times as much as modern equivalents. Simple fixes, motion sensors, staff education, and equipment replacement, can cut bills by 20% or more.
What to write in your book
- An energy audit systematically investigates energy use and waste
- Start by identifying all energy users and collecting baseline data
- Direct measurement with power meters reveals actual consumption
Put these steps in the right order for conducting a school energy audit.
- Measure energy use of major appliances with meters
- Develop recommendations to reduce energy waste
- Present findings to school leadership
- Analyse data to find the biggest energy consumers
- Identify all energy-using systems in the school
- Collect baseline data from electricity and gas bills
✅ Virtual Audit Checklist, Tick as you learn
When analysing audit data, distinguish between evidence and irrelevant facts. A statement can be true without supporting the claim. The school's founding date, the principal's tenure, and the existence of a pool are all true facts, but they provide no evidence about whether lighting is the best savings opportunity.
Strong evidence includes quantitative data (lighting's share of the bill), comparative data (LED vs fluorescent efficiency), and causal mechanisms (motion sensors reduce waste). Good scientific reasoning connects specific evidence to specific claims through logical links.
If lighting is 35% of the bill and LEDs can cut that by 75%, the potential saving is 26% of total electricity use. No other single measure is likely to match that impact. This calculation provides strong quantitative support for prioritising lighting upgrades.
What to write in your book
- Distinguish evidence from irrelevant facts when analysing data
- Quantitative data and causal mechanisms provide strong support
- Good reasoning connects specific evidence to specific claims
Click each sentence that supports the claim.
🧮 Appliance Cost Calculator
Calculate how much any appliance costs to run. Australian electricity averages $0.30/kWh (check your bill for exact rate).
Direct measurement is the gold standard in scientific investigation. Rather than guessing how much energy a device uses, you measure it. Plug-in power meters cost under $30 and can reveal that an old fridge uses 5 kWh per day while a new one uses 1 kWh. These real numbers transform vague concerns into actionable priorities.
Indirect data, like building age or enrolment numbers, can provide context but cannot replace measurement. A 1950s building might be inefficient or might have been retrofitted. Only measurement reveals the truth. This emphasis on empirical evidence is core to the scientific method.
A school might assume its new interactive whiteboards are energy-efficient because they are modern. Measurement might reveal that 20 whiteboards left in standby mode consume more power than the entire staff room. Without measurement, this hidden load would never be detected.
What to write in your book
- Direct measurement with power meters is the gold standard
- Indirect data provides context but cannot replace measurement
- Empirical evidence is core to the scientific method
A comprehensive energy audit examines all energy inputs: electricity, natural gas, diesel for generators, petrol for vehicles, and embodied energy in purchased goods. Gas used for heating produces carbon dioxide just as electricity from coal does. Ignoring gas would give an incomplete picture of both costs and environmental impact.
The depth study component asks students to go further: investigate one energy system in detail, propose a specific improvement, and evaluate its feasibility. This might involve calculating payback periods, researching available technologies, or surveying staff and students about behaviour change.
A depth study on school hot water might measure the temperature of water at the tap, inspect pipe insulation, and compare the efficiency of the existing gas boiler against a proposed solar hot water system. The report would include costs, savings, payback time, and carbon reduction.
What to write in your book
- A comprehensive audit examines all energy inputs, not just electricity
- Depth studies investigate one system in detail with specific recommendations
- Evaluate feasibility using costs, savings, payback time and carbon reduction
At the start of this lesson you were told that the average Australian school spends over $50,000 a year on electricity, and studies show that 30% of that energy is simply wasted. An energy audit turns measurements into money.
Now that you've designed and carried out your investigation, what did you find? Where was the energy being wasted in your school, and did any finding surprise you?
Before you begin, estimate:
A classroom has 8 fluorescent tube lights, each 36 W. They are left on for 10 hours per school day, 200 days per year. At $0.30 per kWh, what is the annual cost of lighting this classroom? And if LEDs using 18 W each provide the same brightness, what would the annual saving be? Use E = P × t and Cost = E × rate. Show your estimates.
Model answers (click to reveal)
📖 Model Answers
▼MCQ Answers
1. AEnergy (kWh) = Power (kW) × Time (hours).
2. B2,000 W = 2 kW. E = 2 × 3 = 6 kWh.
3. AStar rating indicates relative efficiency within a product category.
4. CControlled variables are kept constant (e.g., room temperature).
5. BSaving = 150 × $0.30 = $45/year. Payback = $300/$45 = 6.7 years.
SAQ 1, Energy Audit Steps (3 marks)
Model answer: To conduct a valid and reliable energy audit of the science laboratories, I would follow these steps:
First, I would create an inventory of all electrical devices in each lab: lights, fume cupboards, fridges, hot plates, computers, projectors, and chargers. For each device, I would record its power rating from the nameplate or measure it with a plug-in power meter (wattmeter).
Second, I would measure usage time by observation or by asking staff, how many hours per day is each device actually used? Some devices like fridges run 24/7, while others like hot plates run only during classes.
To ensure accuracy, I would take multiple power readings at different times (e.g., startup vs steady state), use the same power meter for all measurements, and record all data in a structured table. I would also note the room temperature and time of day to identify if heating/cooling loads vary.
Third, I would calculate annual energy consumption (kWh) and cost ($) for each device using E = P × t and Cost = E × rate. I would then rank devices from highest to lowest consumption. The top 20% of devices typically account for 80% of energy use, these are the "energy hogs" to target first.
Finally, I would identify savings opportunities: replacing old fridges with efficient models, switching to LED lights, installing timers or motion sensors, eliminating standby power with smart powerboards, and improving insulation. Each recommendation would include a cost-benefit analysis showing payback period.
SAQ 2, Lighting Calculation (4 marks)
Model answer:
Fluorescent lighting:
Total power = 50 fittings × 2 tubes × 36 W = 3,600 W = 3.6 kW
Annual hours = 8 h/day × 200 days = 1,600 h
Annual energy = 3.6 kW × 1,600 h = 5,760 kWh
Annual cost = 5,760 kWh × $0.30/kWh = $1,728
LED lighting:
Total power = 50 fittings × 2 tubes × 18 W = 1,800 W = 1.8 kW
Annual energy = 1.8 kW × 1,600 h = 2,880 kWh
Annual cost = 2,880 kWh × $0.30/kWh = $864
Savings:
Energy saved = 5,760 − 2,880 = 2,880 kWh/year
Cost saved = $1,728 − $864 = $864/year
Replacing fluorescent tubes with LEDs would halve the school's lighting energy consumption and save $864 annually in this building alone.
SAQ 3, Motion Sensor Depth Study Design (5 marks)
Model answer:
Aim: To investigate whether installing motion sensors in classrooms reduces lighting energy consumption compared to manual switching.
Hypothesis: If motion sensors are installed, then lighting energy consumption will decrease by at least 25% because lights will automatically turn off when classrooms are unoccupied during breaks, lunch, and after school.
Variables:
• Independent: Presence or absence of motion sensors (sensor classrooms vs control classrooms)
• Dependent: Lighting energy consumed (kWh) measured over a 4-week period
• Controlled: Same number and type of lights, same room size, same school term, same timetable/occupancy patterns, same power meter used
Method:
1. Select 4 matched pairs of classrooms (same size, orientation, number of lights).
2. Install motion sensors in one classroom of each pair; leave the other as manual control.
3. Attach data-logging power meters to the lighting circuits in all 8 classrooms.
4. Record lighting energy consumption continuously for 4 school weeks.
5. Also record occupancy using simple observation logs to verify sensors are working correctly.
6. At the end, remove sensors and repeat for another 4 weeks with roles reversed (crossover design) to control for room-specific effects.
Analysis: Calculate mean daily lighting energy for sensor and control rooms. Calculate percentage reduction: ((control − sensor) / control) × 100. Perform the calculation for each matched pair and average the results. Calculate cost savings at $0.30/kWh and extrapolate to all classrooms in the school.
Presentation: Present data in a table showing each classroom's energy use. Create a bar graph comparing sensor vs control rooms. Include a cost-benefit analysis: sensor cost ($80 each) vs annual savings. Conclude whether the hypothesis was supported and discuss limitations (e.g., sensors may trigger falsely if set too sensitively, holiday periods not tested).
🔄 Revisit These Concepts
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In 2019, Tiptoe Primary School in rural Victoria became one of the first Australian schools to disconnect entirely from the electricity grid. A 50 kW solar array, 80 kWh battery storage, and smart energy management system now supply 100% of the school's electricity. During school holidays, excess solar charges the batteries fully; during term, the batteries discharge to cover morning and evening demand. The school saved $15,000 in the first year, money reinvested in student resources. You monitor energy production and consumption in real-time via a dashboard, making energy science part of daily school life.
Stadium Energy Audits in the AFL
In 2023, the AFL conducted a comprehensive energy audit of all 18 member clubs' training facilities. The audit found that lighting accounted for 45% of electricity use, followed by heating/cooling (30%) and equipment (15%). Simple changes, LED retrofits, smart thermostats, and timers on hot water systems, reduced average facility energy use by 22%. The Richmond Football Club at Punt Road Oval cut its annual electricity bill by $28,000 through a student-assisted audit partnered with RMIT University. Players now compete to see which team can achieve the lowest energy intensity per training session, science and sport combined.