Fuel Type Comparison
Gas vs Electric Tankless Water Heater Cost
Gas models cost more upfront but offer higher flow rates and lower operating costs. Electric models are cheaper to install but may struggle in cold climates. Here's the full comparison.
Gas Tankless
Higher PerformancePros
- Higher flow rates for large homes
- Works during power outages (with standing pilot)
- Lower operating costs in most regions
- Better for simultaneous multi-fixture use
Cons
- Requires gas line and venting
- Higher upfront installation cost
- Annual maintenance recommended
- Venting adds complexity and cost
Electric Tankless
Lower Upfront CostPros
- Lower purchase and installation cost
- No venting required
- Higher energy efficiency rating
- Compact size — fits almost anywhere
- No combustion risk
Cons
- Lower flow rate — struggles in cold climates
- May require 200-amp electrical panel upgrade
- Higher electricity costs in many regions
- Not ideal for large homes with high demand
Our Recommendation
Choose gas if you have an existing gas line, need to supply 2+ bathrooms simultaneously, or live in a cold climate. The higher upfront cost pays for itself through lower operating costs within 5–7 years.
Choose electric if you have a small home (1–2 bathrooms), no gas line available, want the cheapest installation, or live in a warm climate where incoming water temperature is above 60°F.
Operating Cost Comparison Over Time
While electric tankless heaters have higher efficiency ratings on paper, natural gas is cheaper per BTU in roughly 80% of US markets. A gas tankless unit typically costs $250–$400 per year to operate, while an electric model runs $300–$530 annually.
Over a 20-year lifespan, this translates to $5,000–$8,000 in total energy costs for gas versus $6,000–$10,600 for electric. Combined with the longer warranty periods typically offered on gas units, the total cost of ownership often favors gas despite the higher upfront price.
Installation Complexity
Gas tankless installation is more involved, requiring proper venting (stainless steel Category III or IV vent pipe), adequate gas line sizing (typically 3/4" minimum), and a condensate drain for condensing models. This adds $300–$1,500 to the installation cost.
Electric installation is simpler but may require upgrading your electrical panel to 200 amps and running 2–3 dedicated circuits of 40–60 amps each. Panel upgrades alone can cost $300–$2,000, potentially narrowing the cost gap.
Climate Considerations
In cold climates (northern US and Canada), incoming groundwater can be as low as 35–45°F. Electric tankless units struggle to raise water temperature by 70+ degrees at useful flow rates, often providing only 2–3 GPM — barely enough for one shower. Gas units handle this temperature rise easily at 6–8+ GPM.
In warm climates (southern US), incoming water at 65–75°F means electric units only need a 40–50 degree rise, delivering adequate flow rates for most homes at significantly lower installation cost.