A residential client requires a new gas-fired hot water tank. The existing tank is 151 litres (40 US gallons), and during peak use (showers, laundry, dishwasher running simultaneously), they frequently run out of hot water. The household consists of 4 people. Based on typical sizing guidelines, what is the most appropriate minimum size for the new hot water tank?

Question: A residential client requires a new gas-fired hot water tank. The existing tank is 151 litres (40 US gallons), and during peak use (showers, laundry, dishwasher running simultaneously), they frequently run out of hot water. The household consists of 4 people. Based on typical sizing guidelines, what is the most appropriate minimum size for the new hot water tank?

Answer options:

• 113 litres (30 US gallons)
• 189 litres (50 US gallons) ✅ 227 litres (60 US gallons)
• 303 litres (80 US gallons)

Correct answer: 227 litres (60 US gallons)

Explanation: For a household of 4 people with high peak demand, a 227-litre (60 US gallon) tank is generally recommended as a minimum to ensure sufficient hot water during simultaneous use. A 189-litre tank might still be insufficient, while a 303-litre tank would likely be oversized for most typical residential applications and consume more energy unnecessarily.