Plumbing Service
Tankless Water Heater Installation
A tankless water heater delivers continuous hot water and frees up floor space, but a good install depends on the right sizing, venting, and gas or electrical capacity. Plumbing Advisors helps you weigh the tradeoffs and connect with install help.
Plumbing Advisors provides guidance and connection assistance. Independent providers perform the plumbing work and confirm availability, pricing, timing, and credentials.
On this pageOverview
Plumbing Advisors Editorial TeamEditorial StandardsSource-CheckedQuick summary
- Heats water on demand for continuous hot water and space savings
- Available in gas and electric, each with different requirements
- Sizing is based on flow rate and incoming water temperature
- Often needs new venting and a gas-line or electrical upgrade
- Call to talk through fit and get connected
About tankless installation
A tankless water heater, sometimes called an on-demand unit, heats water only as it flows through, instead of keeping a tank full of hot water around the clock. That difference is the whole appeal: hot water does not run out the way a tank's reserve can, the unit takes up a fraction of the space, and there is no standby energy lost to reheating a tank all day. A good tankless installation, though, is less about the box on the wall and more about matching the unit to your home, from how much hot water you use at once to how the unit is vented and fueled.
The two main types are gas and electric, and the choice shapes both performance and what the install requires. Gas models generally deliver higher flow rates and are common for whole-home use, but they need dedicated venting and often a larger gas line to feed the burner. Electric models are simpler to vent and well suited to smaller demand, but may call for added electrical capacity. On top of that, sizing is done by flow rate rather than gallons, and the unit has to raise your incoming water temperature enough even in winter. Because venting, gas-line sizing, electrical capacity, and permits all vary by city, county, and state, a local professional is the one who confirms what your home needs and installs it to code.
Signs a tankless water heater may be a good fit
You keep running out of hot water
If a tank's reserve drains during back-to-back showers or heavy use, a properly sized tankless unit can supply continuous hot water instead of leaving you waiting for a tank to reheat.
You want to reclaim space
A tankless unit mounts on a wall and is far smaller than a storage tank. If you want to free up a closet, garage corner, or utility space, that compact footprint is a real draw.
Your tank just failed
A failed or leaking tank is a natural moment to consider upgrading rather than swapping in another tank. Planning the conversion then lets you weigh venting and fuel needs before committing.
You run several hot fixtures at once
Homes that often use multiple showers or appliances simultaneously benefit from sizing a unit, or units, to that peak flow. It is a good reason to have the demand assessed properly.
You want lower standby energy loss
Because a tankless unit does not keep water hot all day, it avoids the standby loss a tank has. For the right household and a long stay in the home, that efficiency can add up over time.
You are remodeling or adding fixtures
A renovation that adds bathrooms or high-flow fixtures can outpace an older tank. Installing tankless during a remodel is a chance to size hot water to your new layout from the start.
What to know
When you need it
- You want continuous hot water that does not run out mid-shower
- You are replacing a failed tank and want to upgrade
- You need to reclaim the floor space a tank takes up
- Your household runs several hot water fixtures at once
- You are after a more efficient way to make hot water
Common causes
- A storage tank that has failed or reached the end of its life
- Frustration with running out of hot water under heavy use
- Limited space that a bulky tank takes up
- A desire to lower standby energy loss from a tank
- A remodel or new fixtures increasing hot water demand
What to check first
- Estimate how many hot water fixtures you run at the same time
- Note whether your home has gas or you would use electric
- Check the space available and a route for new venting
- Consider how cold your incoming water gets in winter
- Gather details on your current unit, fuel source, and panel
When to call a pro
- You need the unit sized to your home's peak flow rate
- A gas-line upgrade or new dedicated venting may be required
- An electric model may need additional electrical capacity
- You want the install done to code and safely
- You are unsure whether gas or electric fits your home
Gas vs. electric tankless
The main choice when going tankless is between a gas and an electric unit. Neither is simply better; the right pick depends on your demand, your existing service, and your home.
Gas tankless
Gas units generally deliver higher flow rates, which makes them a common choice for whole-home use and colder climates where incoming water needs a bigger temperature boost. The tradeoff is that they need dedicated venting and often a larger gas line to supply the burner, which adds to the install. They suit homes with existing gas service and higher hot water demand.
Electric tankless
Electric units are simpler to install in some ways since they do not require combustion venting, and they work well for smaller homes or lower simultaneous demand. The catch is that high-output electric models can draw a lot of power and may require added circuits or panel capacity. They are a good fit where gas is unavailable or demand is modest.
How to decide
Weigh your peak flow rate, how cold your incoming water gets, whether you already have gas service, and your panel's capacity. A professional can size either type to your home and tell you what venting, gas, or electrical work the install would actually involve before you commit.
What a typical tankless installation visit includes
- Help choosing gas or electric and sizing by flow rate
- Installation and connection of the tankless unit
- Dedicated venting for a gas model where required
- Gas-line sizing or upgrades for a gas unit's burner demand
- Electrical capacity updates for an electric model where needed
- Handling permits where your area requires them
- Testing for safe operation and steady hot water across fixtures
What tankless installation costs
A tankless installation quote should be based on the inspected scope, access, parts or equipment, permits, restoration, and urgency. Compare written quotes that describe the same work.
Typical tankless installation costs
| System | Typical installed cost |
|---|---|
| Electric tankless water heater, installed | $1,050–$3,700 per unit |
| Gas tankless water heater, installed | $2,300–$6,350 per unit |
Labor costs
| Labor | Typical cost range |
|---|---|
| Labor to install the unit | $730–$2,600 per unit |
Additional project costs
| Additional work | Typical cost range |
|---|---|
| New or upgraded gas line | $430–$2,100 |
| Annual descaling / maintenance | $110–$340 |
Additional per-item costs
| Additional item | Typical cost range |
|---|---|
| Electrical upgrade for an electric unit | $530–$3,000 per unit |
What affects the cost
- Whether the unit is gas or electric and its flow-rate capacity
- Venting requirements for a gas model
- Gas-line sizing for the unit's burner demand
- Electrical capacity needed for an electric model
- Permit and code requirements in your city, county, or state
- How difficult the install location is to access
- Local labor rates in your area
Typical service process
- 1Review your hot water demand, fuel source, and space
- 2Choose gas or electric and size the unit by flow rate
- 3Connect with a plumbing professional that services your area
- 4Have any venting, gas, or electrical upgrades planned
- 5Install, connect, and vent the tankless unit to code
- 6Test for safe operation and steady hot water across fixtures
How to choose the right pro
- Choose a licensed, insured plumbing professional where your state or city requires it
- Ask for a total installed quote that includes venting and any gas or electrical work
- Have them size the unit by flow rate for your household, not by guess
- Confirm permits and code items are included in writing
- Ask what warranty covers the unit and the installation work
- Read recent reviews from homeowners in your area
How Plumbing Advisors helps
Plumbing Advisors helps you understand tankless tradeoffs, gas versus electric, and what proper sizing and venting involve, then connects you with plumbing professionals that service your area. Gas-line sizing, venting, electrical capacity, and permits vary by city, county, and state, so a local professional handles those details. Availability and pricing vary by location and provider.
Frequently asked questions
What are the main benefits and tradeoffs of going tankless?
Tankless units provide continuous hot water, take up far less space, and avoid the standby energy loss of keeping a tank hot. The tradeoffs are a higher upfront cost, sizing that must match how much hot water you use at once, and installs that often need new venting or a gas-line or electrical upgrade.
Should I get a gas or electric tankless water heater?
Gas units generally deliver higher flow rates and suit whole-home use, but often need a larger gas line and dedicated venting. Electric units are simpler to vent and good for smaller demand, but may require added electrical capacity. The right choice depends on your demand, your existing service, and your home, which a professional can assess.
How is a tankless water heater sized?
Tankless sizing is based on flow rate, measured in gallons per minute, and on how much the unit must raise your incoming water temperature. A professional adds up the fixtures you might run at once and accounts for colder incoming water in winter, so the unit keeps up without falling short.
Does a tankless install usually need venting or gas-line changes?
Often, yes, for gas models. A gas tankless unit typically needs dedicated venting and may require a larger gas line to supply its higher burner demand, while an electric model may need added electrical capacity instead. A local professional will confirm what your home needs and what code requires.
Do tankless water heaters need maintenance?
Yes. Periodic descaling, often once a year, helps clear mineral buildup from the heat exchanger, especially in hard-water areas, and keeping the inlet filter clean supports performance. Regular maintenance helps protect efficiency and the unit's lifespan.
Sources and further reading
These references support the safety and technical guidance on this page.
Tankless Water Heater Installation guides
Learn before your tankless installation.
Free guides on cost, common problems, repairs, and what to expect — written to help you make the call with confidence.
Do Tankless Water Heaters Provide Instant Hot Water?
Can a Tankless Water Heater Fill a Bathtub?
What Size Water Heater Do I Need?
Tankless Water Heater Maintenance and Descaling
What to Expect During a Tankless Water Heater Installation
Gas vs. Electric Tankless Water Heaters: What Your Home Needs
How Much Does Tankless Water Heater Installation Cost?
How to Size a Tankless Water Heater: Flow Rate and Temperature Rise
Is a Tankless Water Heater Worth It? Benefits and Drawbacks
Choose your area
Tankless Water Heater Installation near you
Find tankless water heater installation in your state or city. Availability varies by location and provider.
Tankless Water Heater Installation by state
AlabamaAL6 cities
ArizonaAZ8 cities
ArkansasAR5 cities
CaliforniaCA9 cities
ColoradoCO8 cities
ConnecticutCT6 cities
DelawareDE5 cities
FloridaFL8 cities
GeorgiaGA8 cities
IllinoisIL9 cities
IndianaIN8 cities
IowaIA6 cities
KentuckyKY6 cities
LouisianaLA6 cities
MarylandMD7 cities
MassachusettsMA8 cities
MichiganMI9 cities
MinnesotaMN7 cities
MississippiMS5 cities
MissouriMO8 cities
NevadaNV6 cities
New HampshireNH5 cities
New JerseyNJ8 cities
New MexicoNM5 cities
New YorkNY10 cities
North CarolinaNC8 cities
North DakotaND5 cities
OhioOH9 cities
PennsylvaniaPA9 cities
Rhode IslandRI5 cities
South CarolinaSC6 cities
South DakotaSD5 cities
TennesseeTN7 cities
TexasTX10 cities
VirginiaVA8 cities
WashingtonWA8 cities
West VirginiaWV5 cities
WisconsinWI7 cities
Need Plumbing Help Now?
Call Plumbing Advisors to connect with help for leaks, drains, water heaters, sewer lines, burst pipes, toilets, faucets, and more.
No-obligation request · Availability varies by location and provider