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Top Tankless Water Heater Service Companies in Honolulu, Hawaii Ranked

Upgrading to a tankless water heater is a smart move for many Honolulu homeowners, offering endless hot water, significant space savings, and improved energy efficiency. This on-demand system heats water directly as it flows through the unit, eliminating the need for a bulky storage tank. Finding the right local professional for your tankless water heater installation or repair is crucial, as the process involves specific assessments of your home's plumbing, gas, or electrical systems to ensure optimal performance and safety.

Roto-Rooter Plumbing & Water Cleanup

Roto-Rooter Plumbing & Water Cleanup

2106 Lauwiliwili St Ste 101j, Kapolei, HI 96707

Roto-Rooter Plumbing & Water Cleanup offers comprehensive residential and commercial plumbing services in Honolulu, HI. Their experienced team handles a wide range of plumbing needs, including sewer line inspections and repairs, water heater installation and repair, drain cleaning, leak detection, and gas line installation. They specialize in trenchless sewer repair and provide emergency plumbing services available 24/7 throughout the year. With expertise in floodwater cleanup and mold remediation, Roto-Rooter is equipped to manage urgent water damage situations efficiently. Serving Kapolei and surrounding communities, they combine local knowledge with advanced tools like hydro jetting to address plumbing challenges effectively.

4.9
1.5k Reviews
Shoreline Plumbing

Shoreline Plumbing

honolulu

Shoreline Plumbing is a locally owned plumbing company serving Honolulu, HI, and surrounding Oahu communities. They offer a wide range of plumbing services including water heater installation and repair, drain cleaning, sewer line repair, leak detection, and fixture upgrades. The team specializes in both traditional and tankless water heaters, providing thorough inspections and reliable repairs to maintain home comfort. Shoreline Plumbing also handles sewer line assessments and root intrusion solutions to keep plumbing systems flowing smoothly. Their approach emphasizes clear communication, honest pricing, and long-lasting results, aiming to prevent recurring plumbing issues rather than quick fixes.

4.9
267 Reviews
Roto-Rooter Plumbing & Water Cleanup

Roto-Rooter Plumbing & Water Cleanup

3049 Ualena St Ste 713, Honolulu, HI 96819

Roto-Rooter Plumbing & Water Cleanup provides comprehensive plumbing services in Honolulu, HI, serving both residential and commercial customers. Their experienced plumbers handle a wide range of issues including sewer and drain cleaning, water heater repair and installation, leak detection, sewer line repair with trenchless methods, and water damage cleanup. The company is familiar with Honolulu's unique plumbing challenges such as aging infrastructure and weather-related impacts. Roto-Rooter offers 24/7 emergency plumbing services to address urgent problems like burst pipes, sewer backups, and flooding. They also provide advanced capabilities like hydro jetting and trenchless sewer repair to efficiently restore plumbing systems. Serving Honolulu and surrounding communities on O'ahu, Roto-Rooter is fully licensed and insured. Their team uses modern tools and techniques to comply with local codes and ensure effective solutions. The company is available around the clock, 365 days a year, for emergency plumbing needs.

4.8
2.1k Reviews
Malama Drains “Rooter & Drain Cleaning”

Malama Drains “Rooter & Drain Cleaning”

honolulu

Malama Drains "Rooter & Drain Cleaning" provides plumbing and drain cleaning services in Honolulu, HI. They offer a range of solutions including drain cleaning, sewer camera inspections, water heater installation and repair, leak detection, and sewer line repairs. The company uses advanced equipment such as hydro-jetting and video cameras to diagnose and clear plumbing issues efficiently. Malama Drains is locally owned and operated, serving the community with eco-friendly practices and a commitment to customer care. They also provide 24/7 emergency plumbing services for urgent repairs.

5.0
43 Reviews
Cubellis Plumbing LLC

Cubellis Plumbing LLC

honolulu

Cubellis Plumbing LLC is a family-owned and operated licensed plumbing contractor serving Honolulu, HI. With over 20 years of experience, they provide a wide range of plumbing services including water heater repair and installation, leak detection, repiping, gas line installation, and garbage disposal repair. As a member of the Moen Plumber Network, they specialize in installing Moen Smart Water products and offer island-wide service. Cubellis Plumbing also provides extended services during weekends, holidays, and after hours. Their expertise includes tankless water heater repair and gas water heater services.

5.0
29 Reviews
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Understanding Tankless Water Heaters for Island Homes

Often called on-demand or instantaneous water heaters, these systems provide hot water only when you need it. This can be a major advantage in Honolulu, where space is often at a premium in homes and condos. By eliminating the standby heat loss associated with traditional tank models, a tankless unit can also lead to lower energy bills, a benefit for any household budget 1. The core technology involves a powerful heat exchanger that activates when a hot water tap is turned on, rapidly heating the water as it passes through.

Key Considerations Before Installation in Honolulu

A successful tankless water heater project starts with a thorough professional assessment. Local plumbing experts will evaluate several critical factors unique to your home to recommend the best system.

Assessing Your Home's Flow Rate Demand

The most important first step is determining your household's peak hot water demand, measured in gallons per minute (GPM). A professional will calculate this based on the number of bathrooms and appliances that might run simultaneously. An undersized unit will leave you with lukewarm water during peak usage, while an oversized one is an unnecessary expense. Proper sizing is the foundation of satisfaction with an on-demand system 2 3 4.

Choosing Between Gas and Electric Models

This choice significantly impacts installation complexity and cost.

  • Gas Tankless Heaters: These are common for larger homes in Honolulu due to their higher flow rates. However, they require a dedicated, high-temperature venting system, often using stainless steel pipe, to exhaust combustion gases safely to the exterior 2 5 4. Your existing gas line may also need to be upgraded to supply the required volume, which a licensed plumber must handle.
  • Electric Tankless Heaters: These are generally simpler to install as they don't require venting, making them a good fit for condos or homes without gas service. The major consideration is electrical demand; these units draw significant power and often require an upgrade to your home's electrical panel and dedicated high-amperage circuits 2 6.

Installation Logistics: Venting, Space, and Access

Even with their compact size, placement matters. For gas units, the path for new stainless steel venting is a primary planning factor 2 4. The unit itself must be mounted on an exterior wall or in a location with easy access for future maintenance. Your installer will also ensure all local Honolulu building codes and permit requirements are met for a safe and compliant installation.

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The Professional Installation Process

A proper installation by a qualified technician is not a simple swap. It typically involves:

  1. Site Inspection & System Design: Evaluating your current plumbing, gas, or electrical capacity and planning the new system layout.
  2. Preparation Work: This may include upgrading gas lines, installing new electrical circuits, or running new stainless steel vent pipes through walls or the roof 2 5.
  3. Mounting & Plumbing: Securing the unit and connecting it to your home's water lines.
  4. Utility Connections: Safely tying into the gas line or electrical panel.
  5. System Startup & Testing: Flushing the unit, checking for leaks, calibrating the temperature, and ensuring all safety features function correctly.

Maintaining Your Tankless System

To protect your investment and avoid costly repairs, regular maintenance is essential. The mineral content in Hawaii's water makes descaling a critical annual task. A professional flush removes scale buildup from the heat exchanger, which can cause inefficiency, overheating, and damage 7 8 9. Technicians will also check and clean the unit's inlet filter, inspect for leaks, and test safety sensors during a routine tune-up.

Common Repair Issues for Tankless Water Heaters

Even well-maintained systems can encounter problems. Familiar issues include:

  • Error Codes & Safety Shutdowns: Often triggered by low water flow, venting blockages, or faulty sensors.
  • Inconsistent Water Temperature: Fluctuations can be caused by a clogged filter, a failing flow sensor, or significant scale buildup.
  • Ignition Failure (Gas Models): Problems with the igniter, gas valve, or air intake can prevent the burner from lighting.
  • Mineral Buildup: As mentioned, this is the most common culprit for reduced performance and efficiency in our local water 8 10.

When these issues arise, it's time to call a specialist in tankless water heater repair. They have the diagnostic tools and expertise to correctly interpret error codes and replace components like thermostats, flow sensors, or ignition assemblies.

Understanding Costs and Incentives

The total investment for a tankless water heater in Honolulu includes the unit, labor, and any necessary upgrades to your home's infrastructure.

  • Installation Cost: For a full installation of a gas or electric tankless water heater, homeowners can expect a total cost ranging from $1,500 to $4,500 or more2 11. This wide range accounts for the unit's quality, the complexity of venting or electrical work, and the specific conditions of your home.
  • Repair Costs: Common repairs like replacing a thermostat or sensor may start around $150, while more complex fixes involving the burner or heat exchanger can reach $80010 12.
  • Potential Rebates: It's always worth checking with Hawaii Energy for current rebates or incentives on high-efficiency tankless water heater models, which can help offset the initial cost 2 13.

Finding a Qualified Honolulu Professional

For projects this specific, experience matters. Look for plumbing companies that explicitly list tankless water heater installation and repair as a core service. They should be properly licensed, insured, and familiar with Honolulu's permit requirements. Reading reviews and asking for references can provide insight into their expertise with these advanced systems. Local providers like All Aloha Plumbing, Steve's Plumbing & A/C Service, and Waialae Plumbing are examples of firms that handle these specialized services 2 7 14 15.

Frequently asked questions

Sources

Footnotes

  1. Tank vs. Tankless Water Heater Cost: 8 Factors to Consider When Choosing a Water Heater - https://www.bobvila.com/articles/tank-vs-tankless-water-heater-cost/

  2. Tankless Water Heaters In Honolulu | All Aloha Plumbing - https://allalohaplumbing.com/oahu/tankless-water-heater-installation/ 2 3 4 5 6 7 8

  3. Water Heater Installation In Oahu, HI | Steve's Plumbing & A/C ... - https://www.stevesplumbinghawaii.com/oahu/plumbing-services/water-heater-installation/

  4. Tankless Water Heater Installation: A Homeowner's Guide - https://www.2-10.com/blog/installing-tankless-water-heater/ 2 3

  5. Tankless Water Heater in Oahu & Maui - Allens Plumbing - https://www.allensplumbinghi.com/plumbing-services/tankless-water-heater/ 2

  6. Tankless Water Heater Installation Cost - Complete Guide - https://cycloneplumbingusa.com/tankless-water-heater-installation-cost/

  7. Tankless Water Heater Installation Near Oahu, HI - https://www.stevesplumbinghawaii.com/oahu/plumbing-services/tankless-water-heater-installation/ 2

  8. Steve's Plumbing & A/C Service® Trusted Tankless Water Heater Repair In Oahu, HI - https://www.stevesplumbinghawaii.com/oahu/plumbing-services/tankless-water-heater-repair/ 2

  9. Tankless Water Heaters: Smart Upgrade or Pricey Hype? - https://www.armadillo.one/resources/tankless-water-heaters-smart-upgrade-or-pricey-hype/

  10. How Much Does Tankless Water Heater Repair Cost? [2026 Data] - https://www.angi.com/articles/tankless-water-heaters-don-t-expect-save-big.htm 2

  11. Reliable Water Heater Repair in Oahu - All Aloha Plumbing - https://allalohaplumbing.com/oahu/water-heaters-hot-water-tanks/

  12. Water Heater Service in Kaneohe, HI - Prestige Plumbing - https://www.prestigeplumbinghawaii.com/residential-plumbing-services/water-heaters/

  13. What is the going rate to install a gas tankless water heater? - https://www.facebook.com/groups/839923376622201/posts/1715675299047000/

  14. Water Heater Repair & Replacement in Oahu - https://waialaeplumbing.com/water-heater-repair-oahu/

  15. Top 10 Best Tankless Water Heater in Honolulu, HI - Services & Professionals - Updated 2026 - Yelp - https://m.yelp.com/search?find_desc=Tankless+Water+Heater&find_loc=Honolulu%2C+HI