Have you ever had your water heater cut out mid-shower, leaving you standing there in cold water and wondering why it keeps happening? Or maybe it takes forever to heat up lately, no matter how long you wait. That’s usually the point where homeowners start thinking about switching to a tankless system.
But what most people don’t realize is that going tankless isn’t just swapping one unit for another. There are a few things about the setup and the ongoing upkeep that can catch you off guard if you don’t know them ahead of time. And if you don’t know those details before you switch, you can end up spending thousands and still not get the endless hot water you were expecting, which is exactly why you’ll want to read the rest before making the jump.
What to Expect During Tankless Water Heater Installation
Switching to a tankless system is not as simple as pulling out the old tank and hanging a new unit on the wall. Tankless water heaters work differently from storage tanks, so your home may need a few adjustments before the new system runs as it should. Here’s what most homeowners don’t realize until installation day:
Your gas or electrical supply may need an upgrade
Tankless water heaters fire much hotter and faster than a tank system, which means they need a stronger fuel supply to keep up. Many homes don’t have gas lines large enough or electrical panels capable of handling the higher amp draw that tankless units require.
If those upgrades aren’t made, the unit can struggle with fluctuating temperatures, random shutdowns, or recurring error codes that make it seem like the heater is malfunctioning when it’s actually underpowered. A proper fuel supply is one of the first things a plumber evaluates before installation.
Proper Venting is Needed for Safety & Efficiency
Tankless systems produce a hotter, more concentrated exhaust than traditional tank heaters, so the venting setup isn’t interchangeable. They must be vented with approved materials and routed correctly to move exhaust out efficiently and safely.
Incorrect venting can lead to poor performance, moisture issues, or even carbon monoxide problems. This is why venting is often one of the biggest differences homeowners notice when they see a tankless system being installed for the first time.
Placement Matters More Than You Think
Where the tankless heater is mounted affects comfort, efficiency, and long-term maintenance. Most units perform best when installed on an exterior wall, allowing shorter vent runs and less piping between the heater and your fixtures. This makes hot water reach your faucets faster and helps the system run quieter.
Placement also has to meet local code requirements and allow enough space for future servicing. A cramped or poorly chosen location can make maintenance harder and reduce overall performance.
This is why you really do need a licensed plumber to handle tankless system installations. One small mistake can leave you with lukewarm water, constant error codes, or worse, a dangerous setup that isn’t up to code.
The Real Cost of Tankless Water Heater Installation
Most homeowners are surprised to learn that switching to a tankless system isn’t just about buying the unit. A tankless water heater itself usually runs $1,000 to $3,000, but the installation can add another $1,000 to $3,000, depending on how much work your home needs. That’s why some people pay closer to $2,000 total… while others get quotes closer to $6,000.
Here’s where the price swings come from:
- Gas vs. electric: Gas tankless models cost more upfront because they produce more power, require more safety systems, and require more infrastructure upgrades, but they deliver efficient performance and endless hot water for busy homes.
- Installation complexity: A direct swap (tankless-to-tankless, same BTU, exact location) can be done in a couple of hours. But converting from a tank? That can mean new gas lines, upgraded venting, and extra plumbing for tankless water heater installation.
- Size and performance: Higher-capacity units, the kind that can run multiple showers at once, cost more. Some homeowners brag that they spent only $400 on a unit that “powers three showers at once,” while premium brands top the price range.
- Brand and warranty: Rinnai, Navien, and similar high-end units cost more due to longer warranties, better support, and features like built-in recirculation.
Because of all these variables, the quote you get should never be a mystery number scribbled on a clipboard. A transparent plumber clearly outlines costs for equipment, labor, upgrades, permits, and warranties, so you know what you’re paying for.
Maintenance Myths: What You Actually Need to Do
A tankless system is very efficient, but it’s not set-it-and-forget-it. That’s the biggest myth. Tankless water heaters last longer than tank systems, but only if you keep up with a few essential maintenance routines. Most people neglect it until they run into error codes, temperature swings, or a lagging system.
Here’s what real maintenance looks like:
- Annual flushing: Using vinegar or a descaling solution keeps the heat exchanger clean. Hard water leaves mineral deposits that can burn out the exchanger long before its time.
- Cleaning or replacing the inlet filter: It keeps sediment from clogging internal components, one of the most common causes of reduced flow or lukewarm water.
- Inspecting venting and condensate lines: This ensures no blockages, leaks, or corrosion could affect performance or safety.
- Checking sensors and flow switches: It helps prevent those random shutdowns homeowners often complain about in reviews.
Many frustrated reviewers say they were told “just flush once a year,” only to discover later that their water hardness required service every six months, or that skipping one cleaning caused an expensive repair.
Common Problems and When to Call for Tankless Water Heater Repair
Tankless systems have warning signs before they fail; you have to know what to look for. The water may take longer to heat, the temperature may jump around, the unit may make loud clicking noises, or an error code may pop up out of nowhere. These minor inconveniences are often early signs that something inside the system needs attention.
Most issues come from simple causes: a clogged filter, scale on the heat exchanger, a faulty sensor, or a flow restriction somewhere in your plumbing. But without the correct diagnosis, it’s easy to misread the problem and let a minor fix turn into a costly part replacement.
A professional plumber can quickly identify what’s really going on and restore your system before the damage spreads. Quick repairs keep your tankless system efficient; waiting too long risks expensive parts, wasted energy, and bigger problems later.
Make the Switch the Smart Way With Expert Plumbing You Can Trust
If your current water heater is slowing down, leaving you with cold showers, or showing early signs of failure, don’t wait for it to die. Upgrading to tankless water heater installation is a great move, but only if it’s done by someone who knows how to set it up properly. Before you buy anything, have a licensed plumber check your system so you know exactly what your home needs. That one step can save you thousands in avoidable mistakes.
When you’re ready to move forward, we at Cisneros Brothers Plumbing, Septic, Restoration & Flood Services are a reliable team to call. We’ll review your setup, map out the safest installation plan, and ensure your new tankless unit performs from day one.
With Isaac Cisneros leading as President of Marketing, the company’s reach continues to expand, strengthening its presence in both the industry and the community.
