Your water heater is one of the most important appliances in your home, accounting for 15-20% of your energy bills. Whether you're replacing a failing unit or upgrading for efficiency, this guide covers everything you need to choose the right water heater for your household.
Types of Water Heaters
Conventional Tank Water Heaters
The most common type, tank water heaters store 30-80 gallons of hot water continuously. They're affordable upfront and work well for most households.
Pros: Lower purchase cost, simple installation, reliable technology
Cons: Standby heat loss, limited hot water supply, larger footprint, 8-12 year lifespan
Tankless (On-Demand) Water Heaters
Tankless water heaters heat water only when needed, eliminating standby energy loss. They're compact, long-lasting, and never run out of hot water.
Pros: Endless hot water, 20% more energy efficient, 20+ year lifespan, wall-mounted design
Cons: Higher upfront cost, may require gas line/electrical upgrades, limited flow rate
Heat Pump (Hybrid) Water Heaters
Heat pump water heaters extract heat from surrounding air to heat water, using 60% less energy than conventional electric tanks.
Pros: Most efficient electric option, lower operating costs, may qualify for rebates
Cons: Higher purchase price, requires 1,000+ cubic feet of space, less effective in cold locations
Point-of-Use Water Heaters
Small tankless or mini-tank units installed near specific fixtures (under sink, near shower). Ideal for supplementing main heater or serving distant fixtures.
Gas vs Electric
Gas Water Heaters
Natural gas or propane water heaters heat water faster and cost less to operate in most areas.
- Recovery rate: 30-40 gallons per hour (vs 20 for electric)
- Operating cost: 30-50% less than electric in most regions
- Requirements: Gas line, venting to outside, combustion air
Electric Water Heaters
Electric units are simpler to install, require no venting, and work anywhere with adequate electrical service.
- Installation: Easier, no venting required
- Maintenance: Fewer components, less maintenance
- Requirements: 240V circuit (30-50 amp for tanks, may need upgrade for tankless)
Sizing Your Water Heater
Tank Water Heaters: First Hour Rating
First Hour Rating (FHR) measures how many gallons of hot water the heater can supply in one hour starting with a full tank. To determine your needs:
| Household Size | Recommended FHR | Typical Tank Size |
|---|---|---|
| 1-2 people | 30-40 gallons | 30-40 gallons |
| 2-3 people | 40-50 gallons | 40-50 gallons |
| 3-4 people | 50-60 gallons | 50 gallons |
| 5+ people | 60-80 gallons | 65-80 gallons |
Tankless Water Heaters: Flow Rate (GPM)
Tankless heaters are sized by flow rate in gallons per minute (GPM). Calculate simultaneous hot water demand:
- Shower: 2.0-2.5 GPM
- Bathroom faucet: 0.5-1.0 GPM
- Kitchen faucet: 1.0-1.5 GPM
- Dishwasher: 1.0-1.5 GPM
- Washing machine: 1.5-2.0 GPM
For example, if you need to run a shower (2.5 GPM) and kitchen faucet (1.5 GPM) simultaneously, you need at least 4.0 GPM capacity.
Temperature Rise
Tankless heater capacity depends on inlet water temperature. In cold climates with 40°F inlet water, you need more power to reach 120°F than in warm climates with 60°F inlet water.
Energy Efficiency
Energy Factor (EF) / Uniform Energy Factor (UEF)
Higher UEF means more efficient operation. Look for:
- Gas tank: 0.60-0.70 UEF (high efficiency: 0.80+)
- Electric tank: 0.90-0.95 UEF
- Gas tankless: 0.80-0.99 UEF
- Electric tankless: 0.98-0.99 UEF
- Heat pump: 2.0-4.0 UEF
ENERGY STAR Certification
ENERGY STAR certified water heaters exceed minimum efficiency standards. They may qualify for utility rebates and federal tax credits.
Key Features
Self-Cleaning Systems
Some tanks include self-cleaning mechanisms that reduce sediment buildup, extending heater life and maintaining efficiency.
Leak Detection
Smart water heaters can detect leaks and send alerts to your phone, preventing water damage.
Recirculation Systems
Dedicated return line or pump system provides instant hot water at distant fixtures, eliminating wait time and water waste.
Condensing Technology
Condensing gas water heaters capture heat from exhaust gases, achieving 90%+ efficiency. They require different venting (PVC instead of metal).
Installation Considerations
- Location: Consider access for maintenance and replacement
- Venting: Gas units need proper venting (atmospheric, power vent, or direct vent)
- Drain pan: Required in some areas to prevent water damage
- Expansion tank: Often required by code with closed plumbing systems
- Permits: Most jurisdictions require permits for water heater installation
Top Water Heater Brands
- Rinnai – Industry leader in tankless technology
- Rheem – Full range of tank and tankless options
- A.O. Smith – Reliable tanks and innovative heat pumps
- Bradford White – American-made quality
Related Resources
- Home Improvement Glossary – Tankless, BTU, Energy Star definitions
- FAQ – Shipping and return policies
- Broan-NuTone Guide – Ventilation products