Key Takeaways

• Make sure you correctly evaluate your household’s hot water requirements and follow your local codes prior to installing a tankless water heater.

• Choose a model with the appropriate flow rate and thermal capacity, taking into account your existing and potential hot water needs and energy efficiency.

• Select a convenient installation location with room, ventilation and easy access to water and power that will help make maintenance easier and the unit perform at its best.

• Collect your tools and premium materials upfront, and don’t forget to observe safety measures — turn off power and gas services, etc.

• Choose gas or electric according to infrastructure, installation and long-term energy savings potential for your home.

• Preventative care and following manufacturers guidance preserve your investment, warranty coverage, and long term dependability.

Tankless water heater install means setting up a water heating system that heats water only when needed, without storing it in a tank. A lot of homeowners choose tankless units for their energy efficiency, consistent hot water flow, and compact form factor. These heaters mount on a wall, consume gas or electricity, and require high-quality water and power connections. Folks are always looking to slash utility bills and gain room in those cramped corners of efficiency, be it a tiny flat or a bustling family abode. Right install is safe and best works, so many select expert pros, yet others carefully DIY it. So, to assist you in determining whether tankless suits you, this post breaks down essential steps, costs, benefits, and the primary considerations prior to beginning.

Pre-Installation Checks

A good tankless water heater install begin with planning. Each pre-installation check is crucial for safety, efficiency, and code compliance. As we’ve learned, it’s best to get these details right to save yourself from expensive regrets down the road.

Sizing

First, determine how much hot water your home will require. Take an inventory of the household, their routines, and how many fixtures may draw hot water simultaneously—such as showers, sinks or washers. For instance, a two bathroom kitchen home will require a water heater that’s capable of supporting multiple taps.

A good baseline is a flow of around 3.25 gpm (around 12.3 lpm). Most homes fare better with a unit rated for 6–7 GPM (22.7–26.5 L/min), which means you can run a shower and a sink concurrently without depleting your hot water. Consider your local incoming water temperature. Colder water requires more energy to heat, so you may need a heater with a higher BTU input. For goodness sake, don’t forget to look at the energy efficiency ratings – going for a high rating model can reduce running costs significantly over time.

Location

Choose a location – inside or outside – that minimizes heat loss and is convenient to access for maintenance. Leave sufficient clearance around the unit not only to accommodate its size but to allow for future servicing. BEFORE INSTALLING: Ensure your proximity to main water lines and, if necessary, gas source for easier installation. Good ventilation is critical, particularly for gas models, in order to prevent combustible gas from accumulating. A cramped sealed closet is not an installation location.

Codes

Check your local plumbing and electrical codes to ensure that your installation is above board. You might require permits prior to beginning any work. Check the manufacturer’s instructions – skipping a step can break local code. If you’re unsure of any regulatory or requirement, call your local building authority—they can help you avoid surprises.

Power

Determine whether you’ll run on gas, liquid propane or electric by what your home currently has in place. For electrics, see if your system can take the load, which could involve upgrading breakers or wiring. If you select gas, ensure the gas line is sufficient for the heater’s requirements. Upgrade plans if you fall short.

Essential Toolkit

A prepared toolkit is the secret for a safe, smooth tankless water heater install. Every tool and material has a specific task, and lacking even one can stymie your progress or cause errors. Take time to check manufacturer requirements and local codes before you begin.

Tools

Adjustable wrenches assist you in manipulating the plumbing attachments, which can be copper, PVC, or even flexible steel. You desire a tight seal—no drips. To vent and intake air, a drill is a must. Driving crisp holes into walls or floors allows you to establish protected exhaust routes for flue gases. Pipe cutters provide nice, neat cuts on pipes, so your joins fit tight. With copper and PVC, a really sharp cutter is a huge difference. Having a level close at hand ensures your unit installs perfectly level—not at an angle that might stress connections.

Materials

Select pipes and fittings that are compatible with your tankless heater’s specifications – typically copper, PVC, or PEX. Top notch parts reduce future leaks and repairs. In frigid locations, cover pipes with insulation to protect them from freezing. Grab sealants and Teflon tape for leakproof threads and joints. For venting, purchase a kit that corresponds with your heater and features a vent hood to keep out rain and critters. Stick to whatever the manufacturer lists for materials.

Safety

ALWAYS turn off power and gas before reaching in. You can’t skip this step!) Adhere strictly to the guide, because every model may have distinct requirements. Improper actions can result in flames or spills. Ensure the work area is ventilated, particularly if working with gas lines. Have a fire extinguisher handy. Follow the rules. Local codes usually have strict guidelines for water heater installation, so do it to avoid fines and keep everyone safe.

Other Essentials

You’ll need a gas line and pressure relief valve to prevent pressure build-up. For a rock-solid, drag-me-around-the-yard kind of mounting, utilize a 2 x 4/plywood mounting box. For electrical, wire and armored cable with the proper gauge. Don’t forget a hot water-rated hose to drain the old heater!

Installation Guide

Tankless water heater require meticulous, incremental install for secure, consistent hot water. Each should be remembered for future patches or updates. A solid workspace makes it all secure and lets you accomplish the task correctly.

1. Decommission Old Unit

Shut off water and gas lines prior to work begins.

Drain every last drop from the old tank. This prevents drips and helps floors remain dry. Direct water through a hose to a drain.

After draining, disconnect water and gas lines. Cut or unscrew pipes with caution—beware of sharp edges and stripped threads. Take out your existing heater and confirm local regulations for disposal – certain regions require specific recycling for metal and/or gas units.

2. Mount New Heater

Hang the new tankless unit on a sturdy wall that can support it. Go with robust screws and anchors.

Ensure that the unit is level – a spirit level is ideal for this! A crooked mount will give you long run problems or decreased flow. Allow a minimum of 30cm around the entire unit for air circulation and service. Cross-reference your install spot meets local safety codes, like staying away from flammables.

3. Connect Water Lines

Copper pipes, ¾” are typical on both cold and hot side. Use a pipe cutter for a clean edge. Secure all connections and inspect for leaks using a dry rag or paper towel.

If your system requests it, provide a crossover valve for recirculation. This reduces wait times for hot water in larger homes. When finished, briefly turn on the water to check for leaks and repair accordingly.

4. Establish Venting

Drill a vent hole, per the manual. Wear a dust mask.

Observe vent rules for your heater model. Concentric vents are a space saver if you’re installing indoors. Inspect the vents regularly to prevent dust, bugs or birds from entering.

Look at the vent pipe for kinks and blockages.

5. Link Gas Supply

Connect the gas line carefully. Install with gas-rated fittings and sealant.

Check for leaks with a gas detector, not just soap water, to be safe. Select the gas type (natural or propane) that suits your supply.

Gas vs. Electric

Opting for a gas versus electric tankless water heater involves considering expenses, energy consumption, installation requirements, and your household’s demand for hot water. Both can provide limitless hot water, but the specifics come into play when selecting what is best suited.

Gas tankless water heaters typically run a bit higher to install, ranging from $1,000 to $3,500. That’s because they require venting and a gas line. At times, you may need to upgrade your gas line or add additional venting, which can increase the price. Electric tankless water heaters typically cost less, $500 to $1,500 to install. No venting, no gas lines, and smaller—roughly 1/3 the size of gas units. All you need is the proper electrical configuration, which is already in most homes. Which is great for tight spots or apartments.

For energy consumption, electric tankless water heaters distinguish themselves. They utilize more than 98% of the energy for heating water, and some even 100%. Gas tankless water heaters, even the best condensing models, clock in at 80-95% efficient. That translates to a greater percentage of the energy you’re shelling out for with electric actually going toward heating water, while gas units lose more in exhaust heat. Over time, this can translate to lower bills with electric units in regions where rates are decent.

Still, gas tankless water heaters heat water faster, and keep up with heavy use better. This is especially good for big families or cold climates, where everyone showers and appliances are running simultaneously. Electric units can have a tough time with numerous taps going at once and sometimes just don’t keep up in large homes. If you already have a gas line in your home, it’s easier to add a gas heater. If you don’t, installing a gas line can be costly and complicated.

Gas heaters last longer, often 20+ years, while electric ones last 10-15. Gas prices can swing a lot and are likely to rise and electricity prices stay more steady. In certain areas, electricity is expensive, which can bump up bills for electric models.

Common Pitfalls

There’s obvious upside to installing a tankless water heater, but errors in the installation can create unsafe conditions, inflate costs, and shorten the system’s life. Understanding where they commonly screw up means you’re more likely to steer clear of these problems.

Venting Errors

Incorrect venting is the number one danger in tankless water heater installs. Using improper materials or neglecting vent upgrades can lead to hazardous gas accumulation, particularly in the case of indoor units. Just as importantly, always cross reference venting configurations with the manufacturer’s guidelines. Certain units require stainless steel venting pipes, others might allow PVC, but a mismatched material can suffocate airflow and cause backdrafts. Obstacles such as nests or debris can clog exhaust routes, so examine the vent path prior to and after installation. Have your chimney swept and inspected—annually if you can—to avoid buildup, and keep the system safe and efficient.

Sizing Mistakes

Selecting the wrong size is simple to do, but the impact is massive. An undersized unit won’t have a problem providing hot water during peak use resulting in “cold water sandwich” issues, low pressure or stop-and-go hot water. To size it right, check how much hot water your family consumes at one time. Take inventory of every shower, sink and appliance and then validate your heater’s flow rate in liters per minute. If you anticipate more people or extra fixtures down the line, size up a little, but don’t go too big as oversizing is expensive and wasteful of energy. Replacing an ancient boiler? Don’t simply equal the old size—maybe you’ve changed!

Code Violations

There are local building codes that set safety and quality standards for the installations. Ignoring them can get you fined or cause rework or worse yet, dangerous conditions. Be sure to check the most recent local codes before beginning, as regulations surrounding venting, gas lines and electrical wiring vary. Get all required permits to demonstrate adherence should there ever be an issue. Document everything–photos, receipts, inspection reports–to cover yourself. When in doubt, call your local authorized or a licensed installer for advice.

Warranty Invalidation

Only installs that adhere to the manufacturer’s instructions will maintain the warranty intact. Keep all paperwork from the install and any annual service, such as flushing out mineral build-up. Tinkering with the unit or bypassing key steps, such as implementing an outdoor model inside, can nullify coverage. Be aware of your warranty’s time frame and limitations.

The Installer’s Edge

Doing the install right is a genuine, meaningful, real difference for tankless water heaters. A good install means you have better energy savings, longer equipment life and less headaches down the road. Many tankless units run 20 years or longer if you maintain them. Selecting the appropriate expert, anticipating your requirements, and making maintenance a priority all provide you with that “installer’s edge”—the advantages of professional quality.

DIY vs. Pro

DIY install sounds less expensive, but it requires plumbing and wiring expertise. If you’re not confident dealing with safely handling gas lines or power, errors can be more costly than hiring a pro. Certain tasks—such as new venting or electrical upgrades—require a licensed professional for safety and to comply with local codes.

Professional installers know the steps: removing the old heater, setting up the new system, and testing for leaks or faults. They’re aware of new regulations, like the impending ban on certain tankless gas heaters in 2029. A pro can help make sure your new heater meets future standards.

Future-Proofing

Choose a tankless version that’s designed to expand with you. If you think your family will expand or you’ll add new fixtures, seek out a unit that can accommodate additional load. Certain newer units integrate with smart home technology or allow you to adjust settings from your phone.

If so, it’s smart to buy energy-saving models. These save up to 1/3 on energy bills over old tanks. Being up to date on new heating tech will help you continue to squeeze the most out of your system for years to come.

Maintenance Mindset

Routine maintenance is essential—flush the unit at least annually, or more frequently if you have hard water. This prevents mineral deposits and keeps things flowing smoothly. Track water quality and service at first sign of trouble.

Know the basics: check the filter, test the temperature (120°F to 140°F is best), and watch for error codes. Addressing minor problems quickly can prevent major problems or premature failure.

Conclusion

Tankless water heaters are a great fit for most homes. They provide consistent hot water, conserve space and reduce energy consumption. Given proper prep, quality tools and a solid plan, the work remains fluid. Leaks, wrong wiring, or skipped steps, watch out, they trip up most folks! Gas and electric both work, but each has its own install requirements. A quality install keeps it safe and keeps it working better for longer. Ready for hot water that lasts and bills that drop! Choose the appropriate unit, design your space and verify your work. For big fixes or hard places, consult a professional. To find out or tell, jump in the conversation below or get in touch for tips.

Frequently Asked Questions

What should I check before installing a tankless water heater?

Make sure your home’s electrical or gas supply is adequate for the unit. Verify water pressure, ventilation and installation space. Of course, always check the manufacturer’s instructions for compatibility.

What tools do I need for a tankless water heater installation?

The standard tools are a drill, wrenches, screwdrivers, pipe cutter and level. You might require plumbing tape, hardware for mounting, and safety gear.

Is it difficult to switch from a tank to a tankless system?

Plumbing and even electrical or gas lines may need to be switched. Need expert install?

Which is better: gas or electric tankless water heater?

Gas units tend to heat water quicker and are better for larger families. Electric versions are simpler to install and maintain. Which is best for you depends on your fuel source and water requirements.

What are common mistakes during installation?

Such as wrong sizing, inadequate ventilation, and wrong connections. ALWAYS adhere to manufacturer instructions and local codes to prevent problems.

Can I install a tankless water heater myself?

A few seasoned DIYers mount units themselves. Professional installation guarantees safety, code compliance, and maximum efficiency.

How can I maintain my tankless water heater?

Don’t forget to regularly descale and flush the system to prevent mineral buildup. Filter check and leak check. For optimal performance, book a professional maintenance visit once per year.