Heat Pump Water Heater vs Gas Calculator: Which Saves More?

💧 Heat Pump vs Gas Water Heater Calculator

Compare annual energy use, savings, and payback period between heat pump and gas water heaters

Unit System:
Quick Presets
🔧 Your Home Details
📊 Your Comparison Results
📋 Water Heater Efficiency Reference
3.5–4.5
UEF Rating
Heat Pump (HPWH)
0.60–0.70
UEF Rating
Standard Gas
0.80–0.95
UEF Rating
Condensing Gas
0.90–0.98
UEF Rating
Tankless Gas
300–400%
Efficiency
HPWH vs Elec.
3,412
BTU per kWh
Electricity
100,000
BTU per Therm
Natural Gas
8.34
BTU per gal/°F
Water Heat Factor
📊 Annual Energy Use by Household Size
Household Gal/Day HPWH kWh/yr Gas Therms/yr HPWH BTU/yr
1 Person20~375~100~1.28M
2 People40~750~200~2.56M
3 People60~1,100~295~3.75M
4 People64~1,175~315~4.00M
5+ People80~1,450~390~4.95M
💡 UEF Ratings Explained
UEF Range Type Efficiency
3.50–4.50Heat Pump (HPWH)350–450%
0.90–0.98Tankless Gas90–98%
0.80–0.95Condensing Gas80–95%
0.60–0.70Standard Gas60–70%
0.90–0.95Electric Resist.90–95%
💱 Energy Unit Conversions
From To Factor
1 kWhBTU3,412
1 ThermBTU100,000
1 ThermkWh29.30
1 CCF GasTherms~1.02
1 MCF GasTherms~10.2
📅 Typical Payback Period by Gas Rate
Elec. Rate ($/kWh) Gas $0.80/therm Gas $1.20/therm Gas $1.60/therm Gas $2.00/therm
$0.08/kWh2–3 yrs1–2 yrs1–2 yrs1 yr
$0.12/kWh4–5 yrs2–3 yrs2–3 yrs1–2 yrs
$0.14/kWh5–7 yrs3–4 yrs2–3 yrs2 yrs
$0.18/kWh8–10 yrs5–6 yrs3–4 yrs2–3 yrs
$0.22/kWh12–15 yrs7–9 yrs5–6 yrs3–4 yrs
💡 Pro Tip — Temperature Rise Matters: The energy needed to heat water is calculated as: Gallons x 8.34 BTU/(gal°F) x Temperature Rise (°F). A higher temperature rise (cold inlet, hot setpoint) increases energy use proportionally for both heater types. Setting your thermostat to 120°F instead of 140°F can reduce water heating energy by 10–15%.
⚡ HPWH Best Conditions: Heat pump water heaters extract heat from surrounding air and work best when ambient air temperature is between 40°F and 90°F (4–32°C). In very cold climates or unheated spaces below 40°F, the unit switches to electric resistance mode, reducing savings. Federal tax credits (up to 30%) and utility rebates can significantly shorten the payback period.

Heat pump water heaters commonly called hybrid electric water heaters. Although the names differ, they reach the same ultra-efficient performance. They surpass average water heaters in size.

As a group, these devices twice or three times more energy-efficient compared to traditional electric water heaters. Even four times efficiency they can reach regarding standard water heater. Traditional model does not generate heat directly.

How heat pump water heaters work and why they are better

Rather, heat pumps operate like refrigerators in reverse. Stand-alone air-source heat pump water heater takes heat from the surrounding air and switch it to warm water in the tank at higher temperature. That differs from a refrigerator, that exhausts heat from the inside space and sends it into the room.

You can buy stand-alone heat pump water heating system as a single unit. These units have integrated tank and back-up resistance heating elements. The electric elements can replace the heat pump and make it a regular electric water heater.

They also work for hybrid function with the pump. In that mode the pump works until a certain amount of hot water is used. Most of heat pump water heaters are hybrids with a traditional mode.

You can set them to run as usual electric water heater. That mode works less, but feels better in cold weather, because it does not take heat from the room. Notably, that the heat pump need enough free air at temperatures above freezing to operate.

For your home it matters to choose the right model. Browsing various options, you find an energy-efficient solution. Some models have features like WiFi-connection, leak detection and glass-lined tanks.

The upfront cost depends on several factors. Size and brand of the unit affects the price. For instance, heat pump water heaters cost between 1200 dollars for 50-gallon tank and 2500 dollars for 80-gallon from high-end makers.

Installation time and available incentives for that you qualify also change the total amount. These water heaters produce zero emissions onsite and fewer greenhouse gases. They give a byproduct of fresh, dry air.

That helps with dehumidification during the whole year.

Heat Pump Water Heater vs Gas Calculator: Which Saves More?

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