How to Choose a Water Heater
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Storage tank models: These hold a reservoir of heated water until it is used.
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Tankless (on-demand) models: These heat water as it passes through the unit rather than storing heated water.
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Heat pump water heaters: These transfer heat from the surrounding air (or ground) rather than directly producing all of the heat.
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Solar units: Use energy captured from the sun to heat water (often needing a backup system).
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Indirect models: Use heat produced by another system (like HVAC) to heat water.
Each type has pros & cons in terms of upfront cost, installation complexity, fuel type, operating cost and suitability for your home.
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Sizing depends on your household’s hot-water usage, fuel type and whether you use a storage tank or tankless model. Key points:
- For storage tank models: you’ll want a tank large enough to meet your “peak hour demand” (when most hot water is used).
- For tankless models: size is about flow rate (gallons per minute) and temperature rise rather than tank capacity.
- For example: for a smaller household (1-2 people) a 30-40 gallon storage model might suffice; for larger families you may need 50+ gallons or a tankless model capable of higher flow.
Choosing the wrong size can lead to running out of hot water (if too small) or unnecessary cost & energy waste (if too large).
- The fuel type matters greatly — it affects availability, installation requirements, operating cost, and long-term efficiency. From the article:
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Electric models can power storage, tankless or heat pump units.
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Natural gas is common for conventional tank or tankless models.
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Propane is used where natural gas is not available.
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Solar can be used in appropriate climates but often needs backup.
Your local utility rates and home infrastructure (venting, gas lines, electrical supply) may restrict options or change the cost-benefit. The Department of Energy's Energy.gov
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More efficient units cost more upfront but can save you money on fuel/energy bills in the long run. Mass Save+1
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Efficiency also has environmental benefits and may qualify for rebates/incentives. Energy Info
When comparing models: look at the EF (or newer metric UEF — Uniform Energy Factor) or ENERGY STAR® certification. Consumer Reports+1
Efficiency is how much hot water you get for the fuel (or energy) you consume. Ahigher number means more efficient. Points to note:
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Beyond type, size, fuel and efficiency, you should review:
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Cost of ownership: Initial purchase price + installation + operating cost over time.
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Installation / space constraints: Some units (tankless, heat pump, solar) may require special venting, space or backup systems.
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Warranty & quality: Check manufacturer warranty periods (e.g., 12-year models) and brand reliability.
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Scope for future usage: If you anticipate more hot water use (more people, remodeling, extra fixtures) account for that now.
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Local regulations & codes: Some regions mandate certain efficiency levels or venting arrangements.
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Fuel availability & price stability: If your region’s fuel cost is volatile or if fuel source may change, plan accordingly.
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Lifecycle considerations: Newer models may offer longer life, better insulation and fewer maintenance issues.
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Yes. Beyond the standard storage tank or tankless, you’ll find:
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Heat pump water heaters which are highly efficient. Metro Flow Plumbing+1
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Solar water heaters (in sunnier regions) to reduce utility cost. Energy Info+1
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Hybrid units or units with advanced controls (e.g., WiFi monitoring, modulating gas valves) in some models. A. O. Smith
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Indirect systems (using your HVAC system’s heat) for some specialized setups. (These advanced options often cost more upfront but may offer meaningful savings or future-proofing depending on your home and usage.)
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While the article is focused on choosing a new unit, it’s helpful to know when replacement is wiser:
- If your current water heater is more than 10-15 years old (typical tank life) or showing signs of corrosion/leaks.
- If hot water supply is inadequate or becomes inconsistent (indicating sizing/fuel/efficiency issues).
- If your utility bills are rising due to poor efficiency of older unit.
- If you’re upgrading your home (adding bathrooms, fixtures) and the current unit can no longer keep up.
In these cases, choosing a new efficient unit may be more economical than continued repairs.
Avoid the following pitfalls:
Choosing a unit that’s too small — you’ll run out of hot water.
Choosing a unit that’s too large — you’ll waste energy and money.
Ignoring fuel cost and availability — e.g., buying a gas unit when gas isn’t available.
Overlooking installation/venting requirements (especially for tankless, heat pump, solar).
Focusing solely on purchase price, not on long-term operating costs.
Not considering maintenance or warranty — a cheap short-lived unit may cost more in the long run.
Neglecting to check local rebates, incentives or efficiency requirements.
Most storage tank water heaters last around 10 to 15 years, depending on water quality and maintenance. Tankless models often last closer to 20 years. If your unit is aging, leaking, or struggling to keep up with demand, it’s usually a sign that replacement is more cost-effective than repair.
EF was the older method used to measure water heater efficiency, while UEF is the newer, more accurate standard. UEF accounts for real-world conditions, so it gives a better sense of how efficiently a water heater will perform in your home. When comparing models, UEF is the rating you’ll want to use.
In most cases, yes. Even though a basic electric tank model might look straightforward, gas, tankless, heat pump, and solar systems involve venting, fuel connections, code requirements, and safety checks. Professional installation helps ensure the unit performs correctly, maintains its warranty, and avoids issues like leaks or carbon monoxide risks.