How to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater EfficiencyHow to Check Water Heater Efficiency

How to Check Water Heater Efficiency — Lincoln, Rhode Island

Complete checklist with climate-adjusted recommendations for Lincoln, Rhode Island

Overview

Older units run 50-60% efficiency. Modern units hit 95%+. Calculate payback period.

DIY FriendlyEasy~45 min

Lincoln note: Incoming water temperatures in cold climates can be 40-50 degrees F, requiring much more energy to heat than in warm regions (where inlet temps may be 70-75 degrees F). This makes water heater efficiency even more impactful on your bills. Heat pump water heaters are less efficient in cold basements — consider a hybrid unit or ensure the installation space stays above 50 degrees F.

Step-by-Step Guide

Locate the data plate and record your unit's specifications

Find the manufacturer's data plate on your water heater — it is usually on the side of the tank near the top or near the gas valve/heating element access panel. Record the brand, model number, serial number, fuel type (gas, electric, propane), tank capacity (gallons), input BTU rating (gas) or wattage (electric), and the Energy Factor (EF) or Uniform Energy Factor (UEF). The serial number often encodes the manufacture date — search the manufacturer's website for how to decode it.

Determine the age and expected lifespan

Decode the serial number to find the manufacture date, or check the data plate for the date of manufacture. Conventional tank water heaters typically last 8-12 years. Tankless units last 15-20 years. If your unit is within 2 years of its expected lifespan, proactive replacement is more cost-effective than waiting for a catastrophic leak. Units over 10 years old are almost certainly operating at reduced efficiency regardless of maintenance.

Check the energy efficiency rating

The Energy Factor (EF) or newer Uniform Energy Factor (UEF) measures how efficiently the unit converts fuel to hot water. Compare your unit's rating to current ENERGY STAR standards. For gas storage tanks: pre-2000 units typically have an EF of 0.50-0.60 (50-60% efficient); current ENERGY STAR units achieve 0.67-0.70 (67-70%); condensing gas units reach 0.80-0.95 (80-95%). For electric storage tanks: most are 0.90-0.95 EF. For heat pump water heaters: UEF of 2.0-3.5+ (200-350% efficient due to heat transfer).

Calculate your annual water heating cost

Water heating accounts for about 18% of the average home's energy bill. To estimate your cost: for gas units, multiply your daily hot water usage (average household uses 64 gallons/day) by 8.33 BTU per gallon per degree of temperature rise, divided by the unit's EF, then multiply by your gas rate. A simpler approach: check your gas bill during a summer month when no heating is needed — most of that gas usage is your water heater. Multiply that monthly cost by 12 for an annual estimate.

Inspect for signs of declining performance

Check for these symptoms of declining efficiency: longer recovery time (running out of hot water faster than before), rumbling or popping noises (sediment buildup), rusty or discolored hot water (anode rod depletion), water pooling around the base (tank corrosion), and the burner flame being yellow instead of blue on gas units (combustion problem). Any of these indicates the unit is operating below its rated efficiency.

Perform basic maintenance to maximize current efficiency

Drain 1-2 gallons from the tank drain valve every 6 months to flush sediment — attach a garden hose and let it run until the water clears. Check and replace the anode rod if it is more than 75% depleted (typically every 3-5 years, about $20-$50 for the rod). Verify the thermostat is set to 120 degrees F — each 10-degree reduction saves 3-5% on water heating costs. Insulate the tank with a water heater blanket ($20-$30) if it is warm to the touch, and insulate the first 6 feet of hot water pipes.

Calculate the payback period for a new unit

Compare your current annual water heating cost to the estimated cost with a new high-efficiency unit. For example: if your old 0.55 EF gas heater costs $450/year, and a new 0.90 UEF condensing unit would cost $275/year, you save $175/year. If the new unit costs $2,000 installed, the payback is $2,000 / $175 = 11.4 years. A heat pump water heater with a UEF of 3.0 might cut costs to $150/year, saving $300/year with a 6-7 year payback. Consider available rebates — many utilities offer $200-$800 for high-efficiency water heaters.

What You'll Need

Tools

- Flashlight
- Camera or phone to photograph the data plate
- Garden hose (for flushing sediment)
- Bucket (for draining)

Materials

- Water heater insulation blanket (optional, $20-$30)
- Pipe insulation foam (optional, $5-$15)
- Replacement anode rod (if needed, $20-$50)

Cost Estimates

DIY Cost

$0-$50 (maintenance supplies)

Professional Cost

$1,200-$3,500 for new tank water heater installation; $2,500-$5,000 for heat pump water heater; $2,000-$4,500 for tankless

Safety Tips

Turn off the gas or electricity to the water heater before performing any maintenance.
Be careful when draining — the water is scalding hot. Keep children and pets away.
Never set your water heater thermostat above 120 degrees F — higher temperatures increase scalding risk and accelerate tank corrosion.
If you smell gas near a gas water heater, leave the area immediately and call your gas company.
Do not block the combustion air intake or flue vent on gas water heaters.

When to Call a Professional

Call a licensed plumber for anode rod replacement if you are not comfortable working with the unit, for any gas line connections, if the unit is leaking from the tank body (replacement required), or if you are upgrading to a different fuel type (e.g., gas to heat pump). A plumber can also perform a combustion analysis on gas units to measure actual operating efficiency.

Pro Tip

Before replacing your water heater, check the federal tax credits and local utility rebates currently available. As of recent years, heat pump water heaters qualify for up to $2,000 in federal tax credits under the Inflation Reduction Act, which can cut the payback period in half. Many utility companies also offer $200-$800 additional rebates.

Common Mistakes to Avoid

Waiting until the water heater fails catastrophically and floods the home, instead of proactively replacing an aging unit.
Never flushing sediment from the tank, which reduces efficiency by 10-20% and shortens the unit's lifespan.
Setting the thermostat to 140 degrees F for extra-hot water, which wastes energy and increases scalding risk.
Replacing a conventional tank with the same type without considering heat pump or tankless alternatives that may have a better payback.
Ignoring the first-hour rating (FHR) when sizing a replacement — an undersized unit runs constantly and wears out faster.