The heater itself
- Tank, tankless or heat pump
- Capacity and recovery rate
- Gas or electric, and efficiency rating
The installation
- Like-for-like swap, or a change of type or location
- Venting changes, especially when switching to tankless or high efficiency
- Gas line sizing or electrical upgrades
- Code items such as an expansion tank, drain pan, seismic straps or relief valve piping
- Access: a tight closet, an attic or a crawl space takes longer
- Removing and disposing of the old heater
- Permits and inspection where required
Comparing quotes
Two quotes can be for different jobs. Check that each one names the same heater size and type and includes the same code work, haul-away and permit.