Choosing between an electric vs gas tankless water heater depends on your home’s energy source, hot water demand, and budget. Electric models are simpler to install and maintain, while gas units typically deliver higher flow rates for larger households. This guide breaks down the key differences to help you decide which system fits your needs.
How Tankless Water Heaters Work
Both electric and gas tankless water heaters heat water on demand—no storage tank means no standby energy loss. When you turn on a hot water tap, cold water travels through a heat exchanger (electric elements or a gas burner) and is heated instantly. This design can reduce energy consumption by 24–34% compared to a traditional tank water heater, according to the U.S. Department of Energy.
Key Differences Between Electric and Gas Tankless Heaters
1. Fuel Source and Availability
Gas tankless water heaters require either natural gas or propane, along with proper venting to the outdoors. Electric models run on standard household electricity and do not need venting, making them easier to retrofit in many homes.
2. Flow Rate and Hot Water Output
Gas units generally offer higher flow rates (gallons per minute, or GPM) than electric models. A typical gas tankless heater can supply 6–10 GPM, enough for simultaneous showers and appliances. Electric units often max out around 4–6 GPM, which may be fine for one or two uses at a time.
3. Installation Requirements
- Gas units: Need a gas line, a vent pipe (often stainless steel), and sometimes a larger electrical supply for the ignition system. Installation is more complex and usually requires a licensed plumber.
- Electric units: Require a dedicated electrical circuit (often 240V) and a breaker panel capable of handling the load. No gas line or venting is needed, so installation is generally simpler and less expensive.
4. Efficiency and Operating Costs
Both types are more efficient than tank heaters, but electric units have higher energy factor (EF) ratings—often 0.98–0.99—because nearly all electricity converts to heat. Gas units typically have EF ratings of 0.82–0.94 due to combustion losses. However, natural gas is usually cheaper per BTU than electricity in most U.S. regions, so operating costs can be lower for gas heaters. The EPA WaterSense program notes that tankless water heaters can save a typical family over $100 per year on energy bills.
5. Upfront Cost and Lifespan
Electric tankless water heaters cost less to purchase (typically $500–$1,200 for the unit) and have lower installation costs. Gas units range from $800–$2,000 for the heater, plus higher installation fees due to venting and gas line work. Both types last 20+ years with proper maintenance, compared to 10–15 years for tank-style heaters.
| Feature | Electric Tankless | Gas Tankless |
|---|---|---|
| Flow Rate (GPM) | 4–6 GPM | 6–10 GPM |
| Energy Factor | 0.98–0.99 | 0.82–0.94 |
| Venting Required | No | Yes |
| Typical Unit Cost | $500–$1,200 | $800–$2,000 |
| Installation Complexity | Low | High |
| Lifespan | 20+ years | 20+ years |
Which One Should You Choose?
If you have a small home or apartment with low hot water demand and want a simpler, lower-cost installation, an electric tankless water heater is often the best fit. For larger households that need high flow rates for multiple simultaneous uses—and you already have natural gas available—a gas unit usually provides better performance and lower long-term operating costs. Always consult a licensed plumber to evaluate your home’s existing infrastructure and local code requirements. The International Association of Plumbing and Mechanical Officials (IAPMO) provides guidelines for safe water heater installation.
Frequently Asked Questions
1. Is a gas or electric tankless water heater more efficient?
Electric tankless water heaters have higher energy factor ratings (0.98–0.99), meaning they waste very little energy. Gas units are slightly less efficient due to combustion losses, but natural gas is often cheaper per unit of heat, so operating costs may still be lower with gas.
2. Can I install a tankless water heater myself?
In most areas, professional installation is required by code. Gas units need proper venting and gas line work, while electric units require a dedicated circuit. Improper installation can lead to safety hazards or void the warranty. Always hire a licensed water heater repair professional.
3. How much does it cost to run a tankless water heater per month?
Operating costs vary by region, usage, and energy prices. On average, a family of four might spend $25–$50 per month on electricity for an electric tankless heater, or $15–$35 on natural gas for a gas unit. Prices vary by region.
4. Do tankless water heaters work with well water?
Yes, but hard well water can cause mineral buildup that reduces efficiency. Installing a water softener is recommended to protect the heat exchanger and extend the heater’s lifespan.
5. What size tankless water heater do I need?
Size depends on the flow rate needed for your household. For example, a shower uses about 2 GPM, a faucet 1 GPM, and a dishwasher 1.5 GPM. Add up the simultaneous demand to find the required GPM. A plumber can help calculate the exact size for your home.
6. How long does a tankless water heater last?
With regular maintenance (like descaling and filter cleaning), both electric and gas tankless water heaters typically last 20 years or more—much longer than a standard tank heater (10–15 years).
Ready to upgrade your water heating? Contact MyTownPlumber today for a free estimate on tankless water heater installation. Our licensed technicians can help you choose the right unit and handle the entire installation, from gas line hookups to electrical connections. We also offer leak detection, drain cleaning, and sewer line repair services to keep your plumbing running smoothly.
By MyTownPlumber Editorial Team