Water Heater Replacement Cost: Tank vs. Tankless, Gas vs. Electric

A water heater replacement budget has two main parts: the unit and the installation. The unit price depends on type (tank vs. tankless), fuel (gas vs. electric), and capacity. Installation depends on how much your existing plumbing, venting, gas line, or electrical supply needs to change to accept the new unit.

Every price in our tools is an editable planning assumption, not a verified national average. Swapping a like-for-like tank is usually the least involved job; moving to tankless or changing fuel types tends to add work. Start from the defaults and replace them with your own local quote.

Not sure whether to fix the old unit or replace it? Use the repair-vs-replace calculator to frame that decision before you budget for a new heater.

The biggest single decision is tank vs. tankless. They differ in up-front cost, installation work, and how they behave in use:

Tankless can lower the long-run operating cost for some households, but the up-front installation premium is real. We do not present energy or lifetime savings as guaranteed — they depend on your usage, local rates, and water conditions.

Fuel type affects both the unit and the installation. A gas unit needs proper combustion air and venting; an electric unit needs adequate circuit capacity and, for some tankless electric models, a substantial electrical service that older panels may not support. Switching fuel types (for example, electric to gas) is a larger, more expensive job because it adds a gas line or an electrical upgrade.

Capacity matters too. A tank is sized by gallons to match household demand; a tankless is sized by flow rate (gallons per minute) and temperature rise. Undersizing leads to running out of hot water; oversizing wastes money. Match capacity to your actual household rather than copying a neighbor.

To frame your budget, decide: (1) tank or tankless, (2) gas or electric, (3) the capacity your household needs, and (4) whether the install is a straight swap or requires new venting, a gas line, or electrical work. Add removal and disposal of the old unit, plus the permit and inspection where required.

Enter your own local unit and labor prices if you have a quote; otherwise start from the editable defaults and adjust. The more your installation deviates from a like-for-like swap, the more the labor line grows.

Read this before planning any work yourself. Water heater replacement commonly involves gas, venting, and/or electrical connections. Gas and regulated-plumbing work are not universally safe DIY tasks. Mistakes can cause gas leaks, carbon monoxide exposure, scalding, electrical shock, water damage, or fire.

In most jurisdictions this work requires a permit, a licensed professional, and an inspection, and building and gas codes vary by location. We do not provide step-by-step instructions for gas, venting, or electrical connections. If you are not certain the work is legal and safe for you to do, hire a licensed plumber or gas fitter and confirm requirements with your local building department.

A like-for-like electric tank swap is sometimes within reach for an experienced DIYer where local code allows, but it still involves plumbing connections, draining a heavy tank, and an electrical circuit. Anything involving gas, combustion venting, a new gas line, or an electrical service change should be done by a licensed professional. Tankless installs in particular tend to require trade expertise.

Even when DIY is technically permitted, a permit and inspection protect you and preserve warranty coverage. Factor the inspection step into your plan.

Permits are common for water heater replacement because the job touches plumbing, gas, venting, and electrical systems that affect safety. Typical items a permit and inspection may cover include proper venting and combustion air for gas units, correct gas-line sizing and connections, an expansion tank or pressure-relief setup, seismic strapping in some regions, and correct electrical circuits. Requirements vary by jurisdiction — confirm locally before you buy the unit.

• Budgeting only for the unit and forgetting installation, permit, and disposal costs.
• Assuming tankless is a drop-in replacement — it often needs gas, venting, or electrical upgrades.
• Skipping the repair-vs-replace analysis and replacing a unit that was still a reasonable repair.
• Under- or over-sizing capacity instead of matching your household demand.
• Treating a national "average" as your quote. Always confirm locally.