Size New Water Heater
1 hourCalculate BTU or kW for household demand; check first-hour rating.
Intermediate1 day
Water Heater Replacement Guide
Complete guide for water heater replacement — step-by-step workflow, tools, checklist, and expert tips to get started.
DIY homeownersplumbers
Workflow
Disconnect Old Unit
1 hourShut gas/electric and water; drain tank completely.
Install and Connect
2-3 hoursSet new unit; connect vent, gas/electric, and water lines.
Inspect and Set Temp
30 minutesSet 120°F; check vent draft and expansion tank precharge.
Tools Used
Checklist
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Compliance
Safety
Install
Quality
Reference Materials
Water Heater SizingTable
Key benchmarks for water heater replacement.
| Household | Tank Size | First Hour Rating |
|---|---|---|
| 1-2 people | 30-40 gal | 40-50 gal FHR |
| 3-4 people | 50 gal | 60-70 gal FHR |
| 5+ people | 75-80 gal | 80+ gal FHR |
Expansion TankFormula
Acceptance volume = system volume × (T2-T1) / (P2-P1) approximate
NEC DisconnectStandard
Electric water heaters require visible disconnect within sight of unit.
Heat Pump in Warm Climates
Heat pump water heaters cut electric bill 60% in basements.
Replace Anode Rod Schedule
Check anode every 3 years — extends tank life 5+ years.
Never Energize Empty
Dry-fired elements burn out instantly.
Safety Notes
- Scalding water from tank — open drain valve carefully.
- Gas leaks — soap-test all joints; evacuate if smell persists.