The day I decided to replace my old tank water heater, I thought it would be a simple “plug and play” job. Spoiler alert—it wasn’t. My first encounter with tankless water heater installation taught me that these modern units pack a lot more complexity than the old tanks ever did.
Between gas lines, venting, and wiring, it’s not exactly a beginner’s DIY task. But being the stubborn fixer I am, I researched, watched countless videos, and called in professional help at just the right time. Here’s everything I learned that can help you handle your own installation—smartly and safely.
What Should You Know Before Starting a Tankless Water Heater Installation?
Before you even think about unboxing the new unit, preparation matters more than the tools. I learned that a successful tankless water heater installation begins with the right setup and a clear understanding of your home’s systems.
First, know whether your home runs on gas or electricity—because each type requires a different approach. Gas models need venting for combustion gases, while electric ones need a dedicated power circuit. I also checked my water pressure and flow rate since tankless units rely on a steady supply to function efficiently.
And here’s the kicker: location matters. Mounting the unit on an exterior wall saved me money by keeping the vent pipe short. It also helped reduce the amount of noise inside the house. If you’re unsure where to place it, stick to a dry, well-ventilated area away from flammable materials.
Should You Go DIY or Hire a Professional?
I’m a big fan of do-it-yourself projects, but some things are better left to experts—tankless water heater installation tops that list. Between high-voltage wiring, gas connections, and building codes, a small mistake can lead to serious safety issues.
A licensed plumber or contractor not only installs it safely but also ensures your system meets local regulations. They can also help you size the unit properly, so you never run out of hot water mid-shower again.
I initially thought I could do it all myself after watching a few YouTube tutorials. But when it came to connecting the gas and venting system, I called in a professional—and I’m glad I did.
On average, professional installation costs anywhere between $2,400 and $5,400, depending on your home setup. That includes the unit, labor, permits, materials, and the removal of your old water heater. Honestly, peace of mind alone is worth that price tag.
What Happens During a Tankless Water Heater Installation?
The process unfolds in four main phases—preparation, mounting, connecting, and testing. Here’s how mine went step by step:
1. Preparation and Safety
I started by shutting off all utilities—gas, water, and power—to make sure everything was safe to handle. Then I drained and disconnected the old tank heater. That part was messy but oddly satisfying.
Once the area was clear, I chose a location that could support the new unit’s weight (about 88 pounds for a 22 lb water heater body). Mounting it on a solid wall ensured it stayed secure for years to come.
2. Mounting the Unit
Using the mounting bracket that came with the unit, I measured and drilled the holes using a level to keep it straight. Then I slid the new heater onto the bracket. For gas models, it’s crucial to install a proper vent system that directs exhaust safely outdoors. Watching Benjamin Sahlstrom’s video helped me visualize this step perfectly.
3. Connections and Wiring
Here’s where precision meets patience. I connected the cold water inlet and hot water outlet using Teflon tape to seal the joints. For my gas model, I made sure the gas line was the right size (larger than the old tank model’s). For electric models, you’ll need a dedicated breaker and the right wire gauge for safety.
4. Testing the System
Finally, I turned the water back on slowly, letting the air escape through open hot water taps. Then I restored the power and tested the system. The hum of the unit and the steady stream of hot water confirmed success. Seeing it work flawlessly made all the effort worthwhile.
How Much Does a Tankless Water Heater Installation Cost?
I’ll be honest—sticker shock is real. The price tag depends on several factors:
| Installation Element | Average Cost (USD) |
| Tankless Water Heater Unit | $1,200–$2,500 |
| Labor & Permits | $1,000–$2,500 |
| Additional Materials (pipes, wiring, vent) | $200–$400 |
| Total Estimated Cost | $2,400–$5,400 |
If your home’s electrical or gas lines need an upgrade, costs can rise further. But in the long run, the energy efficiency and endless hot water make the investment worth it.
Where Can You Find a Qualified Installer?
If you don’t already have a trusted plumber, there are several ways to find professionals certified for tankless water heater installation. Many brands, like Navien, offer installer locators on their websites.
You can also book installation through major retailers such as The Home Depot, which ensures licensed, vetted technicians handle your system safely.
A little research goes a long way here. Reading reviews and comparing quotes helped me choose a reliable pro who didn’t overcharge for basic upgrades.
FAQs About Tankless Water Heater Installation
1. Can I install a tankless water heater myself?
You can, but it’s not recommended unless you’re experienced with plumbing, gas, and electrical work. The process involves high-pressure water lines and sometimes high-voltage connections. A professional ensures safety, code compliance, and optimal performance.
2. How long does it take to install a tankless water heater?
Most professional installations take around 4 to 8 hours, depending on whether they need to reroute pipes or upgrade your gas or power lines. DIY attempts can take much longer and may require multiple trips to the hardware store.
3. Do tankless water heaters need maintenance after installation?
Yes! Regular maintenance ensures efficiency and longevity. I flush my system once a year to prevent mineral buildup, especially since I live in an area with hard water.
4. What are the signs my tankless water heater isn’t installed correctly?
If you notice irregular water temperature, low flow, gas smells, or leaking around connections, contact a plumber immediately. These issues can point to poor installation or venting problems.
The Final Pour of Hot Water Wisdom
If I learned anything from my tankless water heater installation, it’s that preparation and professional help go hand in hand. I love tackling projects, but sometimes knowing when to step back is the smartest move. Watching a professional handle the tough parts taught me more than any online tutorial ever could.
So if you’re planning to upgrade your water system, take your time to plan, budget wisely, and call in the pros when needed. There’s nothing better than turning on the tap and knowing you’ve done it right—the safe, efficient, and smart way.
