Water Heaters & Hot Water Systems
Water heater types, T&P relief valves, anode rods, expansion tanks, and energy efficiency.
- Compare gas, electric, and tankless water heater types
- Explain the function and installation requirements of T&P relief valves
- Describe the role of anode rods and thermal expansion tanks
- State proper gas connection requirements including sediment traps
Lesson 1
Water Heater Types - Gas, Electric & Tankless
Storage Tank Water Heaters
The most common residential water heater is the storage tank type, available in gas-fired and electric models. These maintain a reservoir of hot water ready for use.
Gas Water Heater
Burner at the bottom heats water
Flue runs through centre of tank
Faster recovery than electric
Requires venting to outdoors
Gas supply and sediment trap needed
Electric Water Heater
Two elements - upper and lower
No flue or venting required
Slower recovery than gas
Simpler installation
Higher operating cost in most areas
Tankless (On-Demand) Water Heaters
Tankless water heaters heat water only when a tap is opened. They provide unlimited hot water but have flow rate limitations. Key characteristics:
- No standby heat loss - more energy efficient
- Limited flow rate - may not supply multiple fixtures simultaneously
- Require larger gas supply or electrical service
- Longer service life than storage tanks (20+ years vs 10-15 years)
Gas water heaters have faster recovery but require venting. Electric heaters are simpler to install but have slower recovery. Storage temperature must be 60 C to prevent Legionella, while delivery to showers is limited to 49 C by mixing valves.