Most homeowners pay between $2,000 and $5,500 to install a tankless water heater, including the unit and labor. The exact number depends on your fuel type, unit size, and how much your existing setup needs to change.
So how much to install tankless water heater for your specific home? It comes down to a few key factors, and we’ll walk through each one so you know what to expect before you call a plumber.
Why Tankless Water Heaters Are Gaining Popularity in 2026
More homeowners are switching to tankless systems this year, and it’s not just a trend. Energy prices keep climbing, and tankless units use less fuel than traditional tanks because they only heat water when you need it.
Space is another reason. Tankless units mount on a wall and take up a fraction of the room a traditional tank needs. For smaller homes, condos, or garages being converted into living space, that matters a lot.
Lifespan plays a role too. A tankless water heater typically lasts 20 years or more, compared to 10 to 15 years for a tank model. Even though the upfront cost is higher, many homeowners see it as a long-term investment rather than just another bill.
Rebates and tax credits have also expanded in many states for high-efficiency units, which brings the real cost down for plenty of households.
Average Tankless Water Heater Installation Cost
For most homes, tankless water heater installation cost lands between $2,000 and $4,000 total, with $2,600 being a common average. This includes the unit itself, labor, and basic setup.
Here’s a simple breakdown of what that average covers:
- The tankless unit: $500 to $2,000, depending on size and brand
- Labor for installation: $700 to $2,500
- Removal of your old water heater: usually included, sometimes a small add-on fee
- Basic connections to existing gas, water, and electrical lines
If your home already has the right gas line size, electrical capacity, and venting in place, you’ll likely land on the lower end of that range. If not, costs climb quickly, which we’ll cover in a later section.
Smaller point-of-use units, the kind installed under a single sink or near one shower, can cost as little as $150 to $800 installed. These are a popular choice for additions, guest bathrooms, or workshops where running a full system isn’t practical.
You can read about: How to Install Tankless Water Heater
Tankless Water Heater Installation Cost by Fuel Type
Your fuel choice has a big impact on tankless hot water heater cost. Here’s how the two main options compare.
Electric tankless water heaters
Electric units typically cost $1,200 to $2,500 installed for whole-home models. They’re popular because installation is simpler in homes that already have enough electrical capacity. No venting is needed, since there’s no combustion involved.
The catch is that electric units often need a dedicated high-amperage circuit, sometimes two. If your electrical panel doesn’t have room, you may need a panel upgrade, which adds to the bill.
Gas tankless water heaters
Gas units run higher, usually $2,500 to $5,600 installed. Natural gas and propane models can handle higher flow rates, making them a better fit for larger households with multiple bathrooms.
Gas installations often need a larger gas line than what’s already running to your old tank. They also require proper venting through an exterior wall or roof, which adds labor and material costs.
If you’re comparing tankless hot water heater installation cost between the two fuel types, electric wins on simplicity and lower upfront cost, while gas wins on capacity for bigger homes.
Tankless Water Heater Installation Cost by Unit Size
Size matters, and in the tankless world, size is measured in gallons per minute, or GPM. This tells you how much hot water the unit can produce at once.
- Small units (2-3 GPM): Good for a single bathroom or point-of-use needs. Cost: $150 to $800 installed.
- Medium units (4-6 GPM): Common for smaller homes with one or two bathrooms. Cost: $1,500 to $3,000 installed.
- Large units (7-10 GPM): Needed for larger homes running multiple showers and appliances at once. Cost: $2,500 to $5,500 installed.
A common mistake is buying a unit that’s too small for the household’s peak demand. If two showers and a dishwasher run at the same time and your unit can’t keep up, water temperature drops. Getting the sizing right the first time avoids a costly redo later.
Additional Costs That Affect Tankless Water Heater Installation
The base price only tells part of the story. These extra factors often explain why two quotes for the same job can differ by thousands of dollars.
Gas line upgrades. Tankless units need more fuel flow than tank models. If your current gas line is too small, expect to pay $300 to $1,000 for an upgrade.
Venting changes. Tankless gas units need specific venting, often stainless steel or PVC depending on the model. New venting through a wall or roof can run $300 to $1,200.
Electrical work. Electric units may require new circuits or a panel upgrade. This can add $200 to $1,500 depending on your panel’s current capacity.
Permits and inspections. Many areas require a permit for water heater replacement, especially when gas or electrical work is involved. Permit fees typically run $50 to $300.
Old unit removal and disposal. Most quotes include this, but some companies charge separately, usually $50 to $150.
Water softener or filtration additions. If you have hard water, adding a filter ahead of your tankless unit helps prevent mineral buildup and protects your investment. This can add $200 to $1,000.
Tankless vs. Traditional Water Heaters: Cost Comparison
It helps to see these side by side. Here’s how the numbers generally compare.
| Factor | Tankless | Traditional Tank |
| Unit cost | $500 to $2,000 | $300 to $1,200 |
| Installation cost | $700 to $2,500 | $300 to $1,000 |
| Total installed cost | $2,000 to $5,500 | $800 to $2,200 |
| Average lifespan | 20+ years | 10 to 15 years |
| Energy use | Lower, heats on demand | Higher, constant standby heating |
| Space needed | Small, wall-mounted | Larger, floor space required |
A traditional tank costs less upfront, no question. But over its shorter lifespan, you’ll likely replace it once or even twice in the time a single tankless unit keeps running. Factor in lower monthly energy bills with tankless, and the gap between the two narrows over time.
DIY vs. Professional Tankless Water Heater Installation
It’s tempting to save money by doing this yourself, especially if you’re handy. But tankless water heater replacement involves gas lines, venting, water pressure, and sometimes electrical work. Getting any of these wrong isn’t just costly. It can be dangerous.
Why professional installation matters:
- Gas connections done incorrectly can lead to leaks or carbon monoxide issues
- Improper venting can cause exhaust to back up into your home
- Many manufacturers require professional installation to keep the warranty valid
- Permits often require licensed work to pass inspection
- Plumbers can correctly size the unit based on your home’s actual water usage
DIY might save you $700 to $2,500 in labor, but if something goes wrong, the repair costs and safety risks usually outweigh those savings. For a system this connected to your home’s gas, water, and electrical systems, hiring a licensed plumber is worth the cost.
How to Save Money on Tankless Water Heater Installation
You don’t have to pay the highest end of the range. Here are practical ways to bring your tankless water heater installation cost down without cutting corners on safety.
Get multiple quotes. Prices for the same job can vary by thousands between companies. Get at least three quotes before deciding.
Ask about rebates. Many utility companies and states offer rebates for high-efficiency tankless units. Some federal tax credits apply too, depending on the model’s efficiency rating.
Choose the right size, not the biggest. A unit sized correctly for your household avoids paying for capacity you’ll never use.
Schedule during off-peak seasons. Plumbers are often busier in winter when heaters fail unexpectedly. Scheduling a planned replacement in spring or fall can sometimes mean better pricing and faster scheduling.
Bundle with other plumbing work. If you’re already having work done, ask if combining projects reduces your overall labor cost.
Keep your existing fuel type if possible. Switching from gas to electric, or the reverse, often means the biggest additional costs due to line and venting changes. Staying with what you have keeps installation simpler.
How Does a Tankless Water Heater Work?
A tankless water heater doesn’t store hot water at all. Instead, cold water flows through the unit, passes over a heat exchanger, and comes out hot, all within seconds.
When you turn on a hot water tap, a flow sensor inside the unit detects water movement and activates the heating element, either a gas burner or electric coils. The water heats as it passes through, then flows directly to your faucet or shower.
Once you turn off the tap, the unit shuts off too. No standby heating, no waiting for a tank to refill and reheat. This on-demand process is the main reason tankless systems use less energy than tank models, which constantly maintain a set water temperature even when nobody’s using hot water.
Benefits and Drawbacks of Tankless Water Heaters
Like any home upgrade, tankless systems have real pros and a few trade-offs worth knowing about.
Benefits:
- Endless hot water, no running out mid-shower
- Lower energy bills over time
- Smaller footprint, frees up space
- Longer lifespan than tank models
- Reduced risk of major leaks from a failed tank
Drawbacks:
- Higher upfront installation cost
- May require gas line, venting, or electrical upgrades
- Flow rate limits mean very high simultaneous demand can still stretch capacity
- Requires annual maintenance, typically $100 to $250, to prevent mineral buildup
- Slight delay before hot water reaches the tap on long pipe runs
Is a Tankless Water Heater Worth the Cost?
For most households, yes. The higher upfront tankless water heater cost pays off through lower energy bills, a longer lifespan, and the comfort of never running out of hot water.
The math works best for households that use a lot of hot water daily, families with multiple bathrooms, or anyone planning to stay in their home for years to come. If you’re moving in a year or two, the upfront cost might not pay back in time to matter for resale.
For homes with hard water, factor in the cost of a water softener or filter alongside your unit. Skipping this step can shorten the lifespan of even a high-quality tankless system.
Conclusion
So, how much to install tankless water heater in your home? Most homeowners land somewhere between $2,000 and $5,500, depending on fuel type, unit size, and what upgrades your home needs along the way. Electric units tend to cost less upfront, while gas units handle bigger households better. Either way, getting the sizing and installation right the first time saves you money and headaches down the road.
If you’re ready to get an accurate quote based on your home’s setup, our team at Derks Plumbing handles Tankless Water Heater Installation in Eagle Rock and the surrounding area. We’ll walk through your home, check your existing gas, water, and electrical setup, and give you a clear number before any work begins.
Frequently Asked Questions (FAQs)
How long does tankless water heater installation take?
Most installations take 4 to 8 hours for a straightforward swap. If gas lines or electrical upgrades are needed, it can stretch to a full day or two.
Do I need a permit to install a tankless water heater?
In most areas, yes, especially if gas lines, venting, or electrical circuits are involved. Your plumber can usually pull the permit as part of the job.
Can a tankless water heater run out of hot water?
Not in the way a tank can, but it has a flow rate limit. If demand exceeds that limit, like multiple showers and a dishwasher running together, water temperature can drop.
How often does a tankless water heater need maintenance?
Most manufacturers recommend an annual flush to clear mineral buildup, especially in homes with hard water. This typically costs $100 to $250 per year.
Is a tankless water heater installation cost tax deductible?
High-efficiency models often qualify for federal or state tax credits. Check current guidelines, since eligibility and amounts change from year to year.
What size tankless water heater do I need for a family of four?
Most families of four do well with a 7 to 8 GPM unit for gas, or a higher-capacity electric model, depending on how many bathrooms run at once.
