Nationally, a tankless water heater typically costs about $1,200 to $3,500 installed, with many jobs averaging around $2,500, compared with roughly half that for a standard tank. What moves the price most is fuel type, venting, and whether the gas line or electrical service needs upgrading. Tankless pays off best for households that use a lot of hot water and plan to stay in the home for years.
How much does a tankless water heater cost?
National cost guides put a tankless water heater at roughly $1,200 to $3,500 installed, with averages around $2,500 to $2,600 (Angi, HomeAdvisor). That covers the unit, labor and standard materials. The spread is wide because the installation, not the heater, is where homes differ the most.
Every home is different, so ALJ gives you a written quote after looking at your gas line, venting path and water lines, rather than a number over the phone that changes later.
What drives the price up or down?
| Factor | Why it matters |
|---|---|
| Fuel: natural gas, propane or electric | Gas and propane units deliver the most hot water but need venting and an adequate gas supply. Whole-house electric units often need a major electrical upgrade. |
| Gas line size | A tankless burner needs far more gas at full fire than a tank. Many homes need a larger gas line from the meter. |
| Venting | Condensing units vent through PVC to the outside. The distance and path to an outside wall affect labor. |
| Removing the old tank | Draining, disconnecting and hauling away the existing water heater. |
| Household demand | Several showers and appliances at once may call for a larger unit or two units. |
| Water quality | Hard water may call for isolation valves for flushing and, in some homes, treatment to protect the heat exchanger. |
Tank vs. tankless: side by side
| Standard tank | Tankless | |
|---|---|---|
| Up-front cost | Lower | Higher, often about double installed |
| Hot water supply | Limited to the tank, then a wait to reheat | Continuous, as long as you stay within its flow rate |
| Typical lifespan | About 8 to 12 years | Often 20 years with maintenance |
| Space | Large floor footprint | Compact, hangs on the wall |
| Energy use | Keeps 40 to 50 gallons hot around the clock | Heats only when you run hot water |
| Maintenance | Occasional draining | Periodic descaling flush |
Is a tankless water heater worth it?
Tankless usually makes sense when:
- You plan to stay in the home for five years or more, so the longer lifespan and energy savings have time to add up
- Your household runs out of hot water with the current tank
- You want the floor space back in a small basement or utility room
- Your current tank is near the end of its life, so you are paying for a replacement either way
A new tank may be the better choice when:
- You may sell within a few years
- Your gas line or electrical service would need an expensive upgrade
- Your household's hot water use is modest
We install both, so we can price it both ways. See our water heater replacement page for tank options.
Signs your current water heater is near the end
- Rumbling or popping from the tank (sediment build-up)
- Rusty or discolored hot water
- Water pooling at the base of the tank
- Hot water running out faster than it used to
- A tank more than 10 years old
A leaking tank can flood a finished basement, so it is far better to plan a replacement than to deal with one in an emergency.
"My hot water tank died and flooded the basement but Anthony came out same day to assess and give a quote that was reasonably priced versus other quotes that were double the amount."
Cassandra M., Google review
How to protect a tankless water heater in hard water
Minerals in hard water build up inside the heat exchanger over time and reduce efficiency. The fix is a periodic descaling flush: a small pump circulates a descaling solution through the unit via its service valves. Most manufacturers recommend it about once a year, more often with harder water. It is quick when the isolation valves are installed from day one, which is why we include them.
Pair the flush with your annual furnace tune-up and the whole system gets checked in one visit. Financing is available through our HVAC financing options.
Frequently asked questions
How much does it cost to install a tankless water heater?
National cost guides put most installations between about $1,200 and $3,500, averaging around $2,500. Fuel type, gas line and electrical upgrades, venting and removing the old tank account for most of the difference. ALJ provides a written quote after seeing your home.
How long does a tankless water heater last?
With regular descaling, many tankless units last around 20 years, roughly twice as long as a typical tank water heater.
Will a tankless water heater run out of hot water?
Not the way a tank does. It supplies hot water continuously, but only up to its flow rate. If several showers and appliances run at once, a unit that is too small will not keep up, so sizing to your household matters.
Is a gas or electric tankless water heater better?
Gas and propane units deliver more hot water and suit most whole-house installations. Whole-house electric tankless units often require a significant electrical service upgrade. Electric can make sense for smaller loads or a single bathroom.
Does a tankless water heater need maintenance?
Yes. It should be descaled about once a year, more often with hard water. Isolation valves installed with the heater make the flush quick and inexpensive.
Can I replace my tank with a tankless water heater in one day?
Often, yes. If the gas line and venting are straightforward, a typical swap can be completed in a day. Upgrades to the gas line or electrical service can add time.
Written by the ALJ Heating & Cooling team
Licensed and insured HVAC technicians serving Albany, Latham, Troy, Schenectady, Clifton Park and the Capital Region. BBB Accredited, SBE and MBE certified, and rated 4.9 stars across 198+ Google reviews. This guide is based on what our technicians see on service calls in Capital Region homes.
Last updated November 9, 2026
