If you're ready to ditch that old, bulky water heater, a noritz tankless installation is probably one of the smartest moves you can make for your home's comfort and efficiency. There's something incredibly satisfying about knowing you'll never run out of hot water in the middle of a shower again, but getting from that decision to actually having a working unit on your wall takes a little bit of planning. It isn't just about swapping one box for another; it's about making sure your home's infrastructure is ready for the change.
Noritz has been in the game for a long time, and they've built a reputation for being the "workhorse" of the tankless world. But even the best machine won't perform if it's not put in correctly. Let's break down what you actually need to know before you start drilling holes in your utility room wall.
Why the Setup Matters So Much
A lot of people think they can just pull out their old 50-gallon tank, slap a tankless unit in its place, and call it a day. I wish it were that easy, but tankless units operate on a completely different logic. A traditional tank slowly heats water over hours. A Noritz tankless unit, on the other hand, has to flash-heat water from 50 degrees to 120 degrees in a matter of seconds.
Because of that "on-demand" nature, the unit needs a massive amount of energy all at once. This means your gas line and your venting have to be spot on. If you skimp on the noritz tankless installation process, you'll end up with "cold water sandwiches" (that annoying burst of cold water between hot streams) or, worse, a unit that constantly throws error codes and shuts down when you need it most.
Checking Your Gas Line First
This is the number one thing that catches homeowners off guard. Your old tank heater probably used a relatively small amount of BTUs to keep that water warm. A Noritz unit can require anywhere from 150,000 to nearly 200,000 BTUs. If your gas line is too thin—say, a standard half-inch line that's running a long distance—the unit simply won't get enough fuel to fire up properly.
The cool thing about some newer Noritz models, specifically the EZ series, is that they're designed to work with existing half-inch gas lines in many cases. This is a huge deal because it saves you the massive headache and expense of ripping up floorboards to run a new three-quarter-inch pipe. However, you still have to verify the pressure. If the gas pressure drops too low when the unit kicks on, it's going to struggle.
The Venting Situation
Venting is another area where a noritz tankless installation differs from the old-school way of doing things. You can't just vent these through your old chimney or a standard tin pipe. Most modern Noritz units are "high-efficiency" or condensing models. This means the exhaust gases are actually cool enough that you can use PVC or specialized plastic venting.
But there's a catch: because the exhaust is cooler, it creates condensation. That condensation is slightly acidic. You need to make sure your venting is sloped correctly so that the moisture drains back toward the unit (where it goes into a trap) or out of the system entirely. If water pools in your vent pipes, it'll eventually choke the air intake and kill your heater's performance. Noritz often uses a concentric venting system (a pipe within a pipe) which is great for safety and space-saving, but it requires a bit of precision to install.
Location and Mounting
Where are you putting this thing? One of the best perks of a tankless unit is that it's about the size of a carry-on suitcase. You can mount it in a closet, in the attic, or even on an exterior wall if you live in a climate that doesn't freeze hard.
When you're doing a noritz tankless installation, you want to find a spot that has easy access to: 1. The main water lines. 2. The gas supply. 3. A 120V electrical outlet (yes, they need a little bit of electricity for the computer board and the igniter). 4. A drain for the condensate (if it's a condensing model).
Make sure the wall you're mounting it to can support the weight. While they're lighter than a full tank of water, they still have some heft to them, especially when the heat exchanger is full. Using a proper backing board or hitting the studs is non-negotiable.
Dealing with the Condensate
Since we're talking about high-efficiency units, we have to talk about the "juice." High-efficiency Noritz models pull so much heat out of the exhaust that the steam turns back into liquid water. As I mentioned, this liquid is acidic. You can't just let it drip onto your garage floor or into a cast-iron drain pipe because it'll eventually eat through the metal.
Most pros will install a small condensate neutralizer—basically a little tube filled with limestone rocks—that brings the pH level up to a neutral state before the water heads down the drain. It's a small, inexpensive addition to your noritz tankless installation, but it saves your plumbing in the long run.
Why Water Quality is Your Best Friend
If you live in an area with hard water, you need to be careful. Scale is the enemy of any tankless heater. Because the water passes through small copper or stainless steel pipes in the heat exchanger, any calcium or magnesium in your water will want to bake onto those surfaces.
Over time, this scale acts like insulation, making the unit work harder and harder to heat the water until, eventually, the heat exchanger cracks or clogs. If your water is "crunchy," it's worth installing a water softener or at least a scale inhibitor filter right before the unit. It'll make your Noritz last twice as long, easily.
The Big Question: DIY or Pro?
I'm all for a good weekend project, but a noritz tankless installation is a pretty heavy lift for a casual DIYer. You're dealing with high-pressure gas, electrical work, and precise venting requirements. Plus, most manufacturers (Noritz included) are pretty strict about their warranties. If something goes wrong and they see that the unit wasn't installed by a licensed professional, they might not honor the warranty on that expensive heat exchanger.
If you do decide to tackle it yourself, please, please read the manual from cover to cover. Noritz provides some of the best documentation in the industry, but there are a lot of specific clearances and pipe-sizing charts that you can't just "eyeball."
Initial Startup and Testing
Once everything is piped in and plugged up, don't just turn it on and walk away. You'll need to purge the air out of the water lines first. Open up the hot water taps throughout the house until the sputtering stops. Then, check every single gas connection with a soapy water solution to look for bubbles.
When you finally fire it up, listen to the unit. It should sound like a steady, controlled flame (almost like a high-end gas grill). If it's vibrating excessively or making "whooshing" sounds, your gas-to-air ratio might be off, or your venting might be restricted.
Long-Term Maintenance
After your noritz tankless installation is complete, you aren't totally off the hook. To keep that endless hot water flowing, you should flush the unit with white vinegar once a year. This clears out any minor scale buildup. Most installers will put "service valves" (those little T-handles) on the lines right under the unit. These make it incredibly easy to hook up a small pump and a bucket of vinegar to give the system a bath.
Honestly, once you get the installation right, these units are incredibly reliable. You'll forget what it's like to have to "time" your showers around the dishwasher or the laundry. It's a bit of an investment up front, and the setup requires some technical know-how, but the payoff of never running out of hot water is worth every bit of the effort. Just take your time, respect the gas and venting requirements, and your Noritz should take care of you for the next 15 to 20 years.