To determine the total cost of using tap water, the following factors need to be considered:

1. Operational time data you’ll need for this calculation:
Hour of operation per day (e.g., 8 hours)
Days of operation per week (e.g., 5 days)
Weeks of operation per year (e.g., 50 weeks)

2.  Total Run Time Per Year:
Hours per day x Days per week x Weeks per year = Total Annual Running Hours

3. Water Consumption Information:
Flow rate of tap water (litres per hour)
Total annual water usage = flow rate x total annual running hours

4. Water Cost Calculation:
Find out your cost of water per 1000 litres (including supply and sewerage charges)
Annual water cost = total annual water usage / 1000 x cost per 1000 litres

A closed system, like a chiller or airblast cooler, has running costs primarily associated with electricity consumption. To calculate this:

1. Power consumption factors you’ll need to know:
Voltage of Supply (e.g., 400V)
Phase of supply (single-phase or three-phase)
Current drawn at peak load (in Amps)

2. How to Calculate Power Required per Hour:
Voltage of Supply x Current Drawn at Peak Load ÷ 1000

3. How to Calculate Annual Electricity Cost:
Find out your electricity cost per kW/hr
Annual Electricity Cost = Power per Hour x Total Annual Running Hours x Electricity Cost per kW/hr

4. Total Cost of Ownership
Purchase price of the chiller or airblast cooler
Annualised cost (e.g. spread over 5-10 years)

One of the most compelling reasons to switch to a closed system is its ability to pay for itself through reduced water consumption. To calculate the payback period:

1. Annual Savings:
Annual tap water cost – Annual electricity cost of the system

2. Payback Period Calculation:
Purchase price of the chiller ÷ Annual savings
This result gives the number of years or weeks required for the savings to cover the initial investment

1. Operational Time Data:
Hours of operation per day: 8 hours
Days of operation per week: 5 days
Weeks of operation per year: 50 weeks

2. Total Run Time per Year:
8hours/day x 5 days/week x 50 weeks/year = 2000 hours/year

3. Water Consumption Information:
Flow rate of tap water: Assume 10 litres per minute
Total annual water usage: 10 litres/min x 60 min/hour x 2000 hours/year – 1,200,000 litres/year

4. Water Cost Calculation:
Cost of water per 1000 litres: The average combined water and sewerage cost for UK businesses in 2025 is approximately £3.50 per cubic meter (1,000 litres)
Annual water cost: 1,200,000 litres/year ÷ 1000 x £3.50 = £4,200

1. Power Consumption Factors
Voltage of Supply: 230V
Phase of Supply: Single-phase
Current Drawn at Peak Load: 5

2. Power Required per Hour:
230V x 5A ÷ 1000 = 1.15kWh

3. Calculating Annual Electricity Cost:
Total Annual Running Hours: 2,000 hours (as previously calculated)
Total Annual Energy Usage: 1.15kWh x 2000 hours = 2300kW
Electricity Cost per kWh: Approximately £0.2703 per kWh
Annual Electricity Cost: 2300kW x £0.2703 per kWh = £621.69

4. Total Cost of Ownership:
Purchase Price of the Chiller: Assume £5000 (this is an estimate; actual prices may vary depending upon specification)
Annual Operating Cost: £621.69
Total First-Year Cost: £5000 + £621.69 = £5621.69

1. Annual Savings:
Savings from reduced water usage: £4200 (annual water cost)
Minus Additional Electricity cost: £621.69
Net Annual Savings: £4200 – £621.69 = £3578.31

2. Payback Period Calculation:
Initial Investment: £5000
Annual Savings: £3578.31
Payback Period: £5000 ÷ £3578.31 x 52 = 72.66 weeks

By replacing a tap water cooling system with the G01, a business could recoup its investment in approximately 73 weeks (just over 1 year and 5 months).

Beyond this payback period, the company would continue to save nearly £3,600 annually, while also reducing water waste, improving sustainability efforts, and protecting equipment from mineral build-up and contamination.

Even if a business doesn’t directly pay for its water, excessive use strains local water supplied, increasing the likelihood of future regulatory restrictions or price hikes. A closed system not only saves money but also future proofs cooling processes against rising costs and environmental concerns.

By using real-world data, this framework can be tailored to suit different facilities and operational conditions, helping businesses to make the best cooling decisions for their needs.