Tank type
Good fit: homeowners who want familiar technology, straightforward replacement and lower initial complexity.
Watch for: limited stored capacity, standby losses, tank corrosion and eventual leakage.
How they differ
A traditional storage water heater heats and stores a fixed volume of water. A tankless unit heats water as it flows through the appliance. Tankless systems can reduce standby heat loss and provide long-duration hot water, but they must be sized for the flow rate and temperature rise your household actually needs.
Tankless
Good fit: homes that value space savings, efficiency and extended hot-water use.
Watch for: correct sizing, gas/electrical capacity, venting, water quality and potentially higher installation cost.
Questions to ask before buying
- How many showers, faucets and appliances might need hot water at the same time?
- What is the incoming cold-water temperature in winter?
- Is natural gas, propane or sufficient electrical capacity available?
- Will the existing venting, gas piping or electrical service need upgrading?
- How hard is the local water, and what maintenance does the manufacturer require?
- What are the installed cost, warranty and expected service requirements?
Don't buy tankless by BTU alone
For tankless equipment, the important sizing question is how many gallons per minute the unit can deliver at the required temperature rise. A colder incoming water supply requires more energy to reach the same shower temperature. A qualified installer should verify simultaneous demand, temperature rise, fuel supply and venting before selection.
Bottom line
A tank heater can still be an excellent, economical choice. Tankless can be excellent when it is properly sized and the house supports the installation. Compare the complete installed system rather than choosing from an efficiency label or advertised maximum flow rate alone.
General educational information only. Water-heater installation involves fuel gas, combustion, venting, electricity, pressure and scalding hazards. Follow the manufacturer's instructions and applicable local codes and use qualified professionals where required.