Compare kWh rates, system sizes and real-world case studies—plus a free cost-saving checklist from Acro Refrigeration.
1. Quick kWh-Cost Table (SE Queensland Tariff 11, $0.27/kWh*)
| System Size (Cooling kW)** | Average kWh / hr | Cost / hr | 8-hr Business Day | 250-Day Year |
|---|---|---|---|---|
| 7 kW Split | 2.1 kWh | $0.57 | $4.56 | $1,140 |
| 14 kW Ducted Split | 4.2 kWh | $1.13 | $9.04 | $2,260 |
| 25 kW Light-commercial | 7.5 kWh | $2.03 | $16.24 | $4,060 |
| 50 kW Rooftop Unit | 14.4 kWh | $3.89 | $31.12 | $7,780 |
| 85 kW Rooftop Unit | 23.5 kWh | $6.34 | $50.72 | $12,680 |
*Tariff 11 QLD April 2025; adjust for your retailer.
**kW refers to nominal cooling capacity; kWh consumption based on average COP of 3.3 in 32 °C ambient.
2. How to Calculate Running Costs Yourself
Formula:
Running cost ($) = (Cooling kW ÷ COP) × Electricity rate (¢/kWh) × Operating hours
Example—25 kW unit:
25 kW ÷ 3.3 COP = 7.6 kWh × $0.27 = $2.05/hr
3. Seven Proven Ways to Slash Your HVAC Bill
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Raise set-point 1 °C = up to 10 % energy saving.
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Quarterly filter changes—dirty filters add 5–15 % load.
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Variable-speed drives on supply fans—average 20 % cut.
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Economiser cycle on rooftop units—free cooling below 22 °C.
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BTMS monitoring—detects compressor short-cycling early.
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Night purge strategy for offices—flush heat before start-up.
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Capex vs Opex—replace R-22 systems >15 yrs; modern inverter units halve kWh.
Link: maintenance checklist blog.
4. Case Study: Gold Coast Retail Chain Saves $3,600 per Year
Problem: 14 kW ducted splits short-cycling, high bills.
Solution: Acro Refrigeration installed VSD drives and staged compressors.
Result: 18 % kWh reduction = $3.6 k/yr across three stores, ROI in 14 months.
5. Frequently Asked Questions
What is the cheapest tariff for commercial HVAC?
- Large sites on Tariff 20 or demand tariffs can pay 10–15 % less per kWh.
Does solar offset HVAC costs?
- Yes—rooftop package units run during daylight. A 30 kW solar array can cover ~40 % of annual HVAC kWh.
Should I run AC overnight to “store” cooling?
- No—heat gains overnight usually exceed any benefit. Use night-purge or setback only. </details>
6. Free Cooling Audit & kWh Calculator
Want to see your exact running costs and payback? Book Acro Refrigeration’s free cooling audit—includes a 5-year workmanship guarantee on any upgrades.
📍 Servicing Brisbane & Gold Coast
📞 1300 227 600
📧 workshop@acrorefrigeration.com.au
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