Looking to replace or upgrade your water heater? Use this water heater replacement cost guide to see what the work will cost and what factors affect your total.
How Much Does Tankless Water Heater Repair Cost? [2025 Data]
Normal Range: $200 - $900
Most tankless water heater repairs cost between $200 and $900, depending on repair type, unit brand, and labor rates.
How we get this data
Photo: Westend61 / Getty Images
Photo: Westend61 / Getty Images
Cost Insights
Tankless water heater repair covers fixing issues like faulty heat exchangers, ignition failures, and sensor problems.
The main cost factors include repair type, brand, unit size, labor rates, and whether the heater is gas or electric.
Completing repairs promptly can extend your system’s life and help you avoid the higher cost of full replacement, which can run up to $4,500.
Professional repairs cost $75 to $150 per hour and help ensure your safety, reliable hot water, and optimal system performance.
Always check your warranty and compare multiple quotes to make the most of your repair budget.
This article was created using automation technology and thoroughly fact-checked and edited by an Angi Editor in accordance with our AI policy.
Tankless water heater repair costs range from $150 to $1,300, with most homeowners paying $600 for common repairs. Costs depend on the type of repair, brand, and whether your unit is gas or electric. Understanding these factors helps you budget for a safe, efficient hot water system.
Let’s explore what goes into tankless water heater repair cost and how you can make informed decisions to keep your hot water running smoothly.
Tankless Water Heater Repair Cost Factors
A few key factors influence your tankless water heater repair cost. Here’s what to consider when budgeting for repairs.
Type of Repair
The type of repair needed is one of the biggest influences on your total cost. Common tankless water heater repairs include fixing heat exchangers, ignition systems, sensors, descaling, valve or pipe issues, and electrical components. Each repair comes with its own labor and parts requirements, which can affect your final bill.
| Repair Type | Average Cost Range |
|---|---|
| Heat exchanger repair | $500–$1,300 |
| Ignition or burner repair | $200–$800 |
| Sensor or thermostat | $150–$400 |
| Descaling or flushing | $150–$350 |
| Valve or pipe repair | $200–$500 |
| Electrical repair | $200–$600 |
Heat Exchanger Repair or Replacement
The heat exchanger is the core component that heats your water. If it fails or becomes corroded, your tankless water heater cannot function. While heat exchangers are designed to last, hard water or lack of maintenance can shorten their lifespan.
This repair is essential for ongoing operation, and costs range from $500 to $1,300, depending on the severity and whether a full replacement is needed.
Ignition or Burner Repair
The ignition system and burner are critical for gas-powered tankless water heaters. Issues here can prevent the unit from heating water or even cause safety hazards.
Common causes include faulty ignition switches, dirty burners, or worn-out sensors. Ignition or burner repairs are relatively frequent in older units or those exposed to dust or moisture. Expect costs between $200 and $800.
Sensor or Thermostat Replacement
Sensors and thermostats regulate water temperature and flow. Signs of failure include inconsistent hot water or error codes on the display.
Replacing these parts is a regular part of long-term maintenance, especially in homes with fluctuating water quality. Sensor or thermostat repairs cost $150 to $400.
Descaling or Flushing Service
Mineral buildup from hard water can clog your tankless water heater and reduce efficiency. Descaling removes these deposits, preventing damage to the heat exchanger and other parts.
It’s recommended at least once a year, especially in areas with hard water. Professional descaling services cost $150 to $350.
Valve or Pipe Repair
Tankless systems depend on several valves—such as pressure relief, check, and isolation valves—to operate safely. Leaks, corrosion, or blockages in valves or connecting pipes can cause performance issues or even water damage. Valve or pipe repairs cost between $200 and $500, depending on the parts and access.
Electrical Component Repair
Electrical problems, like failed circuit boards, wiring issues, or blown fuses, can affect both electric and gas models. Gas units may also have more complex control boards. Electrical repairs are less frequent but are vital for safe operation. Costs for electrical repairs range from $200 to $600, depending on the part and complexity.
Type of Tankless Water Heater
The type of tankless water heater—gas or electric, condensing or non-condensing—affects repair costs. Gas models, especially condensing units, have more complex parts and venting, making repairs more involved and expensive.
| Unit Type | Description | Average Repair Cost |
|---|---|---|
| Gas (non-condensing) | Standard gas-powered, basic venting | $200–$900 |
| Gas (condensing) | Advanced, high-efficiency with complex venting | $300–$1,300 |
| Electric | Simpler design, fewer moving parts | $150–$600 |
Condensing models are more efficient but have extra components that can increase repair costs when compared to non-condensing or electric units.
Brand
Your tankless water heater’s brand can impact repair costs due to part availability, price, and warranty coverage. Some brands use proprietary parts that are more expensive or harder to find.
Aftermarket parts can lower costs, but may affect performance or warranty. Well-known brands often have more accessible support, but premium brands may charge more for parts and repairs. Always check if your brand’s warranty covers the specific repair.
Size
The size of your tankless water heater, measured by gallons per minute (GPM) or BTU rating, influences repair cost. Larger units may require bigger, pricier parts and more labor to access and repair.
| Unit Size | Description | Average Repair Cost |
|---|---|---|
| Small (up to 5 GPM) | For apartments or small homes | $150–$600 |
| Medium (6–8 GPM) | Standard single-family home | $200–$900 |
| Large (8+ GPM) | Large households, high BTU | $300–$1,300 |
Materials
Replacement part quality matters. Original equipment manufacturer (OEM) parts are built to the unit’s specifications and may last longer but cost more.
Aftermarket parts can save money but sometimes sacrifice longevity. Specialized materials, like stainless steel heat exchangers, increase both repair and part costs.
| Part Type | Average Cost |
|---|---|
| OEM parts | $100–$800 |
| Aftermarket parts | $50–$500 |
| Stainless steel parts | $200–$1,000 |
Warranties
A manufacturer or extended warranty can significantly reduce your out-of-pocket tankless water heater repair cost. Most warranties cover major components for five to 15 years, but labor may only be covered for the first year or two.
Always check your warranty terms before scheduling repairs, as some work—especially with non-OEM parts—may void coverage. Warranties often exclude routine maintenance, descaling, and damage from improper installation.
Maintenance Plans
Many pros offer preventative maintenance plans for tankless water heaters. These include annual inspections, descaling, filter cleaning, and minor repairs.
The cost of a maintenance plan ranges from $100 to $300 per year, which can be less than the price of a single major repair. Regular maintenance prevents breakdowns, extends your unit’s lifespan, and may be required to keep your warranty valid.
Labor
Labor is a significant portion of tankless water heater repair cost. Licensed plumbers, HVAC technicians, or manufacturer-certified pros all handle these repairs, with hourly rates ranging from $75 to $150. Some pros charge flat fees for common repairs. Labor rates vary by region, and emergency, after-hours, or holiday repairs can increase costs by 20% or more.
Location
Where you live and where your unit is installed both affect repair costs. Urban areas with higher labor rates can increase your bill. If your heater is in a hard-to-reach spot like an attic or tight closet, expect more labor hours. Accessibility issues—such as removing panels or fixtures—can add to your total cost.
Additional Repairs or Services
Sometimes, additional services are recommended along with the main repair. These can include:
Vent cleaning: $50 to $200
Water line upgrades: $200 to $600
Full system diagnostics: $100 to $250
Your pro may suggest these add-ons if related issues are found during the repair, or to prevent future breakdowns.
Tankless Water Heater Repair vs. Replacement
Deciding whether to repair or replace your tankless water heater depends on its age, repair history, warranty status, and repair cost. If your unit is less than 10 years old and the repair is minor, fixing it is often worthwhile. However, if repairs are becoming frequent or the repair cost approaches 50% of the price of a new unit (the “50% rule”), replacement makes more sense.
On average, professional repair costs are $600, while a complete tankless water heater replacement costs $2,500 to $4,500, including installation. Repairing an existing unit may offer a good return on investment if it extends the life of your system and restores efficiency. Replacing an aging or unreliable unit can save money long-term on both repairs and energy bills.
DIY Tankless Water Heater Repair vs. Hiring a Pro
Some homeowners consider DIY repairs to save on labor costs. DIY-friendly repairs include cleaning filters, basic descaling, or resetting the unit. These repairs require basic tools and safety equipment, with parts costing as little as $20 to $100. However, complex repairs—especially those involving gas lines, wiring, or heat exchangers—should always be handled by a certified pro.
DIY repairs can save you $75 to $150 per hour in labor but come with risks. Mistakes can lead to leaks, safety hazards, voided warranties, or code violations. Attempting advanced repairs without the right skills can shorten your water heater’s lifespan and end up costing more in the long run. We recommend calling a local tankless water heater repair pro for anything beyond simple cleaning or filter changes.
Tips to Reduce Tankless Water Heater Repair Costs
Consider the following tips to save on tankless water heater repairs:
Schedule regular maintenance to prevent major repairs.
Address minor issues early to avoid costly breakdowns.
Compare quotes from multiple licensed professionals.
Check warranty coverage before authorizing repairs.
Use high-quality replacement parts for longer-lasting repairs.
Consider a maintenance plan for long-term savings.
Ensure proper water quality to reduce mineral buildup.
Learn basic troubleshooting to identify simple fixes.
How Angi Gets Its Cost Data
Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.
Want to help us improve our cost data? Send us a recent project quote to [email protected]. Quotes and personal information will not be shared publicly.
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