Water Heater Replacement Cost
Two houses on the same street replace the same water heater and pay thousands apart. It is almost never the heater. It is whether the job is a like-for-like swap or a conversion - and this guide shows you which one you are buying before the plumber does.
By the Calculate My Reno Team / Published
Skip to the tool
Open the Home System Replacement Cost Calculator
The heater is rarely why one quote is $1,200 and another is $5,000. The conversion work is. A like-for-like swap - same fuel, same type, same place - is a morning’s work for a plumber. Everything that is not a like-for-like swap is a different job wearing the same name, and this is the page that tells the two apart.
What the heater costs, fitted
Water heaters are priced as a unit, installed. The published cost guides quote them that way and do not split the box from the plumber cleanly, so a quote that shows you a heater price and a separate labor line is worth a question.
| What you are buying | Installed |
|---|---|
| 40 gal tank - gas / electric | $700 - $2,300 / $700 - $1,650 |
| 50 gal tank - gas / electric | $900 - $2,500 / $700 - $1,900 |
| 75 gal tank - gas | $1,300 - $3,500 |
| 80 gal tank | $1,200 - $3,600 |
| Tankless - gas / electric | $1,400 - $3,500 / $1,000 - $3,000 |
| Heat pump (hybrid) tank | $2,000 - $5,800 |
| Expansion tank · permit · haul-away | $150-400 · $50-300 · $75-500 |
Bands are indicative 2026 US contractor ranges from published cost guides (Fixr, This Old House, HomeGuide, Angi). They are not a quote. Of a straightforward tank job, the plumber’s time is usually $300 to $1,500 of the figure above.
The conversion is the whole price story
Read the table again and notice how close together the heaters are. A big gas tank and a gas tankless overlap. That is the point: the heater is not what separates the quotes.
| The job | Added on top |
|---|---|
| Like-for-like swap (same fuel, same type) | nothing - this is the cheap version |
| Tank → tankless | + $750 - $1,550 |
| Electric → gas | + $1,500 - $2,300 |
| Gas → electric | + $700 - $2,500 |
None of that work is optional, and none of it is padding:
- A tankless burns far harder than a tank. It fires at full output on demand rather than trickling away at a stored 50 gallons, so it commonly needs a larger gas line ($350 - $750) run back to the meter.
- Its exhaust is a different temperature, so the old tank’s vent cannot be reused - that is new venting ($400 - $800).
- Going electric to gas means running a gas line and venting. Going gas to electric means a dedicated 240 V circuit and capping the old gas line - and if the panel has no room, you are suddenly reading about electrical panel upgrades instead.
That is why one neighbor paid $1,200 and the other paid $5,000 for “a new water heater.” They did not buy the same job.
How the price is built
water heater replacement cost = heater installed (type × capacity × fuel)
+ conversion work (gas line · venting · 240 V circuit)
+ expansion tank
+ permit and inspection
+ haul-away of the old unit
Run yours through the water heater replacement cost calculator to get a low-typical-high band rather than a single fake-precise number, then price the lines locally.
What moves the total
- Whether it is a conversion. Bigger than every other line on this page combined.
- Fuel. Gas costs more to fit than electric and usually less to run. The install price and the running cost point in opposite directions.
- Capacity. The gap from 40 to 80 gallons is real but modest - a few hundred dollars, not a few thousand.
- Where it lives. A heater in an open basement is a different afternoon from one in a crawlspace, a closet or an attic with a pan and a drain line.
- The extras that are not extras. An expansion tank is required on a closed system in most jurisdictions. The permit is $50 to $300 and buys you an inspection of a gas appliance full of scalding water.
- Emergency versus planned. A heater replaced the day it floods the basement is bought at whatever the price is that day.
Worked example
A 50 gallon gas tank has failed in a house that has always had one.
- The like-for-like swap: 50 gal gas tank, fitted - $900 - $2,500. That is the job.
- Add the expansion tank ($150 - $400), the permit ($50 - $300) and haul-away ($75 - $500).
- Realistic total: roughly $1,175 - $3,700, and most houses land nearer the low half.
Now the same house wants to go tankless:
- Gas tankless, fitted - $1,400 - $3,500. Only a few hundred more than the tank.
- Conversion work: + $750 - $1,550 - the bigger gas line and the new venting, neither optional.
- Same extras on top. Realistic total: roughly $2,425 - $5,850.
The heater changed by a few hundred dollars. The job changed by thousands. That is the entire decision, and it is why the calculator makes you say which one you are doing.
Where water heater quotes go wrong
- Comparing a swap quote to a conversion quote. They are not the same job and the cheaper one is not the better deal.
- Buying the tankless before pricing the gas line. The unit was never the expensive part.
- Being charged twice for the fitting. These bands are installed prices. A separate labor line on top needs explaining.
- Skipping the permit. It is the only independent check on a gas appliance storing water at scalding temperature.
- Budgeting on a tax credit without checking it still exists. The US federal 25C credit was repealed for anything placed in service after 31 December 2025 (One Big Beautiful Bill Act, P.L. 119-21), and Canada’s Greener Homes Grant is closed. What is left is state and provincial, and some of it has already run out of money. Check before you count on it.
- In Canada, not checking whether the tank is rented. A rented water heater is a contract, not an appliance, and that changes the job entirely.
If the heater is going and the furnace is the same age, price them together before you commit to either - see HVAC replacement cost.
Frequently asked questions
How much does water heater replacement cost?
A like-for-like swap is the cheap version of this job. A 50 gallon gas tank runs about $900 to $2,500 fitted and the electric equivalent $700 to $1,900. A tankless is $1,000 to $3,000 electric and $1,400 to $3,500 gas, and a heat pump (hybrid) tank $2,000 to $5,800. Add a permit ($50 to $300), haul-away ($75 to $500) and an expansion tank ($150 to $400) on top. What blows the range open is not the heater - it is conversion work, which can add $750 to $2,500 on its own.
How much does a water heater cost?
The heater on its own is the smaller half of the question, and most published prices you will see quoted are for the unit fitted rather than the box on the shelf. That is deliberate: a plumber quotes the job, not the appliance, and of a straightforward tank swap his time is usually $300 to $1,500 of the total. If a quote gives you a heater price and a separate labor line, check you are not being charged for the fitting twice.
Is a tankless water heater worth it?
It depends almost entirely on what your house already has. A tankless is $1,000 to $3,000 electric or $1,400 to $3,500 gas, which is not far off a big tank - but converting a tank house to tankless adds about $750 to $1,550 of work that is not optional. A tankless burns far harder than a tank, so it usually needs a larger gas line, and its exhaust runs at a different temperature, so the old tank vent cannot be reused. In a house already plumbed for one, the sums look very different from a house that is not.
What size water heater do I need?
Tanks are sized by first-hour delivery rather than by the number on the label, so the useful question is how much hot water your house draws in its busiest hour, not how many people live in it. The common residential sizes are 40, 50, 75 and 80 gallons, and the pragmatic answer for most replacements is the size you already have unless it was leaving you short. Tankless is sized differently again - by flow rate at the temperature rise your incoming water needs, which is why the same model performs worse in a cold climate.
Does a new water heater need a permit?
In most jurisdictions yes, and it is $50 to $300 - a small line that matters more than its size. A permitted job gets inspected, which is the only independent check that the gas, the venting and the pressure relief were done properly on an appliance that stores scalding water under pressure. A contractor who suggests skipping it is telling you something about the rest of his work.