THE SHORT VERSION
- Choose a heat pump, not a plain electric tank, if the space allows. At DOE’s 2025 average prices a plain electric tank costs about $919 a year to run against $384 for a gas tank; a heat pump about $214.
- Electrical is the big unknown. A 240-volt heat pump typically needs a 30-amp circuit and room in your panel, confirmed by an electrician’s load calculation. 120-volt plug-in models use a 15-amp dedicated circuit or even an existing outlet, at the cost of slower recovery.
- The gas side is licensed work: the line is capped gastight and tested, the old vent is removed and its opening sealed. If a furnace shares the chimney, its venting has to be checked.
- Size up: ENERGY STAR suggests one size bigger than your gas tank (two for 120-volt models). Get electrical and plumbing permits.
- Plan before the tank fails. Installed heat pumps run $2,500–$5,000 (Home Depot), plus any panel work. The federal 25C tax credit ended after 2025; state and utility rebates vary.
The switch, in eight steps
A gas-for-gas swap reuses the vent, the gas line and the spot. Switching to electric changes all three, and each involves a different trade. Work through them in this order, ideally while the old heater still works.
Choose heat pump or plain electric
Heat pump in almost every case.
Check the electrical panel
Space and capacity decide 240 V, 120 V or a panel change.
Check the spot
Air, temperature, a drain and height.
Plan the gas side
Cap the line, seal the vent, check the furnace.
Size up
Heat pumps recover more slowly.
Pull the permits
Usually electrical and plumbing.
Price it and find rebates
Compare quotes; check state and utility programs.
Pick the timing
Plan it, or have a stopgap ready.
Step 1: a heat pump almost always beats a plain electric tank
Switching a gas tank to a standard electric tank more than doubles the yearly energy bill for water heating at DOE’s 2025 average prices; a heat pump cuts it. The full comparison is in gas vs. electric water heaters, the details in heat pump water heaters.
| Plain electric tank | 240 V heat pump | 120 V plug-in heat pump | |
|---|---|---|---|
| Energy cost a year, busy household | About $919 | About $214 | About $285 |
| Installed price (Home Depot) | $1,600–$2,400 | $2,500–$5,000 | $2,500–$5,000 |
| Circuit | 240 V, 25 or 30 A | 240 V, typically 30 A | 120 V, 15 A dedicated or shared |
| Needs room air and a drain | No | Yes | Yes |
| Recovery | Slower than gas | Slower than gas in heat pump mode; elements help | Slowest; Rheem’s have no elements |
Running costs: Ember & Tank calculation at 84 gallons a day and DOE’s representative 2025 prices (17.22¢/kWh); the gas tank for comparison is about $384. Circuits: NEC 125% rule for the electric tank; ENERGY STAR installer guide; Rheem spec sheets.
A plain electric tank still fits a closet that can’t get louvers or a duct, a spot that drops near freezing, or a very tight budget. But DOE standards for heaters made from May 6, 2029 will require heat pump technology in electric tanks over 35 gallons, according to A.O. Smith’s summary of the rule.
Step 2: check your panel before you pick a model
An electric water heater needs its own power, and your panel has to supply it. Two questions decide the path: is there space (a free breaker slot, or two for 240 volts) and capacity (spare amps on your service)? ENERGY STAR tells gas-to-heat-pump buyers to confirm the panel “can support the additional load.”
How much current each option draws
| Heater | Circuit | Current |
|---|---|---|
| Standard electric tank, 4,500 W (Rheem Performance Plus) | 240 V; breaker sized at 125%: 25 or 30 A | 18.75 A |
| 240 V heat pump (Rheem ProTerra, 50 gal) | 240 V, 30 A breaker | 21 A maximum, when its elements run |
| 240 V heat pumps on ENERGY STAR’s list | Typically 30 A, some 25 or 20 A | 412 of 425 models list 19–24 A maximum |
| Low-amp 240 V heat pumps (e.g. Ruud “-15” models) | 240 V | 12 A maximum, 2.3 kW |
| 120 V plug-in, dedicated circuit (Rheem) | Its own 15 A, 120 V circuit | Up to 12 A in NEEA’s lab test; 1,100 W compressor |
| 120 V plug-in, shared circuit (Rheem) | A 15 A circuit it can share | Under 7.5 A in NEEA’s lab test |
Sources: Rheem spec sheets; ENERGY STAR certified-product data (October 2026) and installer guide; NEEA lab test (2022). The NEC sizes a storage water heater’s circuit at 125% of its rating: 4,500 W ÷ 240 V = 18.75 A × 1.25 = 23.4 A.
At its peak a 240-volt heat pump draws about as much as an electric tank, since its backup elements are the same 4,500 W. Most of the time only the compressor runs; LBNL calls 240-volt models “energy efficient, power inefficient.”
How an electrician decides whether the panel has room
The National Electrical Code (NEC) gives two methods for an existing home, summarized here from LBNL for the 2023 edition (your state may use another):
- Nameplate method (NEC 220.83): add up installed ratings at 100% of the first 8,000 W and 40% of the rest, plus the larger of heating or cooling if that is being added. In LBNL’s example, a 2,000-square-foot home on 100 amps adds a heat pump for heating and cooling and a 240-volt, 12-amp heat pump water heater, and the calculated load is 65 amps: it fits.
- Metering method (NEC 220.87): take the highest demand in a year of meter data, add 25%, then add new equipment at full nameplate. In LBNL’s example a 4,000 W peak becomes 5,000 W, leaving 19,000 W of a 100-amp service for new loads.
LBNL’s metered data from 11,750 homes found most have plenty of capacity, and appliances rarely draw their full nameplate rating. The squeeze is often breaker spaces: LBNL cites an estimate that about a third of US homes have 100-amp service and limited slots. You can look safely: open the panel door, read the main breaker’s number and count empty spaces. Leave the cover on.
| What you find | Typical path | Ask the electrician |
|---|---|---|
| A 240 V circuit already at the spot, such as one left from an old electric tank | 240 V heat pump on that circuit | Do the breaker and wire match this model’s nameplate? |
| No circuit, two free spaces, load calculation shows room | New 240 V circuit; ENERGY STAR says typically 30 A with 10-gauge wire | How long is the run, and is it in the quote? |
| One free space, or a tight load calculation | 120 V dedicated plug-in, or a low-amp 240 V model | Does its first-hour rating cover our busiest hour? |
| No free spaces, but a lightly used 120 V outlet near the heater | 120 V shared-circuit model | What else is on that circuit, and does the outlet need GFCI protection? |
| Busy 100 A service, or an EV charger, heat pump or induction range planned too | Load-management device, or a panel upgrade planned for the whole house | Will the inspector accept the device? Does the utility need to upgrade the service? |
General guidance from ENERGY STAR, LBNL, PNNL and the manufacturers cited here. An outdated or damaged panel may need replacing whatever you choose. The load calculation and your inspector decide.
120-volt plug-in models: the way around the panel
The 120-volt heat pump water heater was built for this switch. A study by Pacific Northwest National Laboratory (PNNL) and DOE estimates 10–15 million single-family homes with fossil-fuel water heaters lack the panel capacity for a 240-volt, 30-amp model. Rheem says its plug-in “easily replaces a standard gas water heater”; A.O. Smith says its Voltex 120V plugs into “a shared circuit wall outlet.”
Dedicated circuit
Good
- Faster recovery: Rheem lists 29 gallons an hour at a 60°F rise
- Needs one breaker space, not two
Watch for
- Needs a new 15 A circuit if none is free
- Rheem’s current sheet lists a 50-gallon size only
Best for: One free breaker space, no room for 240 volts.
Shared circuit
Good
- Often no electrical work at all
- Sizes to 80 gallons; Rheem’s uses a built-in mixing valve to stretch the stored water
Watch for
- Slow recovery: Rheem lists 12 gallons an hour at a 60°F rise
- Someone has to check what else is on the circuit
Best for: A full panel, a lightly loaded outlet nearby, and patience with slow recovery.
In PNNL’s field study of 17 New Orleans homes, no gas-to-120-volt install needed electrical upgrades, but many needed an electrical assessment to trace what shared the circuit. Laundry-room heaters often shared with the washer; washers under 10 years old should peak below 10 amps, the researchers note. DOE’s permitting checklist adds that outlets in basements and laundry rooms need GFCI protection.
Circuit pausers and smart panels
Circuit pausers and smart panels switch a lower-priority load off when the home’s total current nears a limit; LBNL lists devices that pause “EVSE charger or heat pump water heater” among options for today, and since the 2023 NEC an energy management system’s setpoint can count in the load calculation, up to 80% of the panel rating. But a 2023 California market study (CalNEXT) reports a device that failed inspection because the inspector wasn’t sure the code allowed it. Confirm with your permit office first.
Step 3: check that the old spot works for a heat pump
A heat pump takes its heat from the room, so the room matters more than it did for gas. Four checks, covered in depth in heat pump water heaters:
- Air volume: most 240-volt models need about 700 cubic feet (ENERGY STAR installer guide); Rheem lists 700 for its shared-circuit 120-volt model and 1,200 for its dedicated one. Smaller rooms need a louvered door or ducts.
- Temperature: ENERGY STAR advises a space that stays 40–90°F. Rheem’s ProTerra models run from 37°F; below that, 240-volt models fall back to their elements. Rheem’s 120-volt models have no elements; another 120-volt model in PNNL’s study has a 900-watt backup element.
- Condensate: DOE’s checklist, citing the plumbing code, requires a line sloped at least 1% to a floor drain, laundry sink, standpipe or similar, not straight into a drain pipe. No drain nearby means a condensate pump.
- Size: PNNL found the typical 120-volt model about 72 inches tall and 26 inches across, avoided crawlspaces, narrow stairs and cramped closets, and twice moved a washer and dryer to fit one.
If the old spot fails, moving the heater may cost less than forcing it in; see where a water heater can go.
Step 4: cap the gas line and deal with the vent
Both jobs below are licensed work, and both are inspected.
Capping the gas line
A closed valve isn’t enough. The California Plumbing Code, quoting the National Fuel Gas Code (NFPA 54), says each outlet, “including a valve,” must be closed gastight with a threaded plug or cap, and a disconnected outlet “shall be capped or plugged gastight.” DOE’s permitting checklist has inspectors confirm it (IFGC 404.15). ENERGY STAR says capping is “typically nominal” in cost.
If the water heater was your last gas appliance, ask the gas utility about its monthly customer charge and what closing the account involves.
The vent, and the furnace it may leave behind
ENERGY STAR says the old vent penetrations “need to be sealed”; in PNNL’s study the installer removed the vent and sealed the chimney opening at every conversion. The catch: a gas furnace sharing that chimney is left alone in a flue sized for two, an orphaned appliance in DOE’s term, which may not draft properly and whose exhaust can condense.
A.O. Smith’s instructions say that when a water heater leaves a common vent, each remaining appliance must be tested and the vent resized to the National Fuel Gas Code tables. This Old House puts a chimney liner at $500–$700. More in what makes one installation cost more and water heater venting. Keep a carbon monoxide alarm while any gas appliance remains.
Step 5: size up, because a heat pump recovers slowly
A 40,000 BTU/h gas burner reheats water much faster than a compressor. ENERGY STAR says that when switching from gas you will usually need to size up, “from a 40-gallon to a 50-gallon or from a 50-gallon to a 65-gallon,” and its installer guide says 120-volt units typically go two sizes up (40-gallon gas to 65). Compare first-hour ratings, not gallons:
| Heater | Tank size | First-hour rating |
|---|---|---|
| Gas tank, 40,000 BTU/h (Bradford White RG250T6N) | 50 gal | 89 gallons |
| 240 V heat pump (Rheem ProTerra) | 50 / 65 / 80 gal | 67 / 76.6 / 87 gallons |
| 120 V dedicated plug-in (Rheem PROPH50 T0 RH120) | 50 gal | 51 gallons |
| 120 V shared circuit (Rheem PROPH50 / PROPH80 T0 RH120-M) | 50 / 80 gal | 55 / 84 gallons |
| 120 V shared circuit (A.O. Smith HPTV-80) | 80 gal | 93 gallons |
Sources: manufacturer spec sheets; ENERGY STAR certified-product data for the A.O. Smith model. Rheem’s shared-circuit models store water at up to 140°F and mix it down, which raises the first-hour rating but not the 12 gallons an hour they recover.
Matching that gas tank’s first hour takes about the 80-gallon 240-volt size. PNNL’s team chose 80-gallon 120-volt models for homes with a soaking tub, back-to-back baths or a history of running out. Count your busiest hour with our sizing worksheet.
Step 6: expect electrical and plumbing permits
A fuel switch touches gas, plumbing and wiring. DOE’s heat pump water heater permitting checklist (written with the New Buildings Institute) recommends one combination permit, but many places issue electrical and plumbing permits separately. It lists:
What the permit office may ask for, and the inspector checks
- Electrical load calculations showing the service can carry the new load (NEC 220)
- A branch circuit rated at least 125% of the heater’s marked rating, labeled at the panel
- Gas outlets capped gastight where a gas heater was replaced
- Condensate drain sloped to an approved receptor, with a backup pan or shutoff where an overflow would cause damage
- The usual water heater items: relief valve and discharge pipe, cold-water shutoff, seismic straps where required
- Manufacturer specifications and installation manual
Ask which contractor pulls which permit before work starts. More in permits and inspections.
Step 7: what the switch costs, and what helps pay
| Item | Published figure | Source |
|---|---|---|
| Heat pump water heater, installed | $2,500–$5,000 | Home Depot national range |
| Gas tank to gas tank (for comparison) | $1,600–$2,400 | Home Depot national range |
| Labor and materials on top of the heater | $1,000–$3,000 | ENERGY STAR’s informal contractor survey (2024) |
| New electrical or gas lines when switching fuel | Budget $1,500–$2,000 | This Old House |
| Capping the gas line | “Typically nominal” | ENERGY STAR |
| Chimney liner for a furnace left behind | $500–$700 | This Old House |
| Subpanel / panel upgrade to 200 A | $400–$1,750 / $1,300–$3,000 | This Old House |
Home Depot’s ranges include equipment, labor, permits and haul-away; it says conversions and extra work can cost more. The other figures are national estimates, not quotes. Compare real quotes with our quote guide.
Running costs favor a heat pump: about $214 a year for a 240-volt model and $285 for Rheem’s 120-volt plug-in, against $384 for the gas tank in our heavy-use example at DOE’s 2025 prices. The gap shrinks where electricity is dear and gas cheap; see gas vs. electric.
Incentives in 2026
- Federal tax credit: ended. The IRS says the 25C credit covers improvements made through December 31, 2025. Pages still advertising it for 2026 installs are out of date.
- State Home Energy Rebates (HEAR): the federal law caps them at $1,750 for a heat pump water heater, $4,000 for panel work and $2,500 for wiring, for households at or below 150% of area median income. DOE says they are “now available in select states”; your state energy office knows whether yours is one.
- Utility and state programs: amounts and rules change often. Efficiency Maine, for example, offers a $1,200 instant discount on heat pump water heaters at participating retailers. More in rebates.
Step 8: switch before the old tank fails
ENERGY STAR recommends replacing proactively rather than waiting for a leak, with quotes in hand. Tanks last about 10–12 years on its figures, so start planning around year 10; see how old your water heater is.
If the tank has already failed, you have three realistic options:
- Gas for gas. Fastest and cheapest; Home Depot offers same-day tank installs at no extra charge in many areas. Plan the switch for next time.
- A loaner, then the heat pump. One California plumber’s state-funded program installed temporary heaters during the one to two weeks electrical permits and work took, and conversions rose from under 1% to 17%. Silicon Valley Clean Energy offers loaners in its emergency program through March 2027 or until funds run out. Ask local installers and your utility.
- A 120-volt plug-in now, if the spot has the air, a drain and a usable outlet, and the model is in stock. Installs took 4–8 hours in PNNL’s study.
In the middle of an emergency? Start with the first 10 minutes.
Readiness checklist
Check these before you call installers
- Your current heater’s label: gallons, input (BTU/h) and age
- Room size in cubic feet (length × width × ceiling height) and the coldest temperature the space reaches
- Is there a floor drain, laundry sink or standpipe within reach for condensate?
- Your main breaker’s rating (100, 150, 200 amps) and how many breaker spaces are free
- Any 240-volt circuit or 120-volt outlet near the heater, and what else is on it
- Does the water heater vent join a furnace vent or share a chimney?
- Is the water heater your last gas appliance?
- Other electric upgrades planned in the next few years: EV charger, heat pump, induction range
- Rebates available at your address, and whether they need preapproval
- Your busiest hour of hot water use, to size the new tank
Photos of the heater, the space and the panel (door open) help installers quote; see the photo checklist.
Common questions
Can I replace a gas water heater with an electric one?
Yes. A licensed installer caps the gas line, removes the vent and seals its opening, and connects the new heater to a 240-volt circuit or, for a 120-volt plug-in heat pump, an outlet. Choose a heat pump if the space allows: a plain electric tank costs more than twice as much to run as a gas tank at average prices.
Do I need a panel upgrade for a heat pump water heater?
Often not. LBNL’s analysis of metered homes found most have plenty of spare capacity, and the problem is often free breaker spaces. A 120-volt plug-in model needs one space or none, and load-management devices are another option. An electrician’s load calculation settles it.
Can a heat pump water heater plug into a regular outlet?
Some can. Rheem and A.O. Smith sell 120-volt models with a power cord; some need their own 15-amp circuit, others can share one with light loads such as a washer. They recover more slowly, so ENERGY STAR’s installer guide suggests going two sizes up from a gas tank.
Can I cap the gas line myself?
No. Codes require the outlet to be capped or plugged gastight, not just turned off, and the work is permitted and inspected. A licensed plumber or gas fitter does it and tests for leaks. ENERGY STAR says the cost is typically nominal.
What happens to the chimney when I remove a gas water heater?
The water heater’s vent is removed and the opening sealed. If a gas furnace shares the chimney, it is left alone in a flue sized for two, and its venting must be checked; it may need the vent resized or a liner, which This Old House puts at $500–$700.
Will my energy bills go up if I switch from gas to electric?
With a plain electric tank, almost certainly: about $919 a year against $384 for a gas tank in our heavy-use example at DOE’s 2025 average prices. With a heat pump they usually go down, to about $214, though the savings shrink where electricity is expensive and gas is cheap.
How long does it take to switch?
Install day itself took four to eight hours per home in PNNL’s 120-volt field study. Electrical work and permits can add one to two weeks, and a utility service upgrade can take months, which is why planning ahead matters.
Sources
Sources checked October 4, 2026. Prices, codes and rebates change. Check current details with your installer and local permit office.
- What goes into the cost of installing a heat pump water heater? (Feb. 2, 2024) ↗ · ENERGY STAR
- Best practices: installing heat pump water heaters (installer guide, 2024) ↗ · ENERGY STAR
- Heat pump water heaters (siting guidance) ↗ · ENERGY STAR
- ENERGY STAR certified water heaters dataset (heat pump listings, maximum amps, read October 2026) ↗ · ENERGY STAR / EPA
- Heat pump water heater permitting and inspection checklist (with New Buildings Institute, 2024) ↗ · U.S. Department of Energy
- Low-power electrification, the NEC and building energy codes (DOE codes webinar, April 18, 2024) ↗ · Lawrence Berkeley National Laboratory
- Field study of 120-volt heat pump water heaters in the Big Easy (ACEEE Summer Study 2024) ↗ · Pacific Northwest National Laboratory and U.S. Department of Energy
- Plug-in heat pump water heaters: an early look to 120-volt products (Aug. 30, 2022) ↗ · Northwest Energy Efficiency Alliance (NEEA)
- Market study of household electric infrastructure upgrade alternatives for electrification (CalNEXT ET22SWE0057) ↗ · VEIC for CalNEXT
- ProTerra plug-in heat pump water heater with HydroBoost, 120V shared circuit, spec sheet (07.25) ↗ · Rheem
- ProTerra plug-in heat pump water heater, 120V dedicated circuit, spec sheet (07.25) ↗ · Rheem
- ProTerra hybrid electric heat pump with LeakGuard spec sheet (07.25) ↗ · Rheem
- A.O. Smith announces new residential heat pump water heater (Voltex 120V, Sept. 12, 2023) ↗ · Plumbing & Mechanical
- Performance Plus electric water heater spec sheet (XE50T09EL45U1) ↗ · Rheem, hosted by Home Depot
- Residential atmospheric vent gas water heaters spec sheet (RG250T6N) ↗ · Bradford White, hosted by Young Supply
- Code Q&A: electrical requirements for water heaters (NEC 422.13) ↗ · EC&M
- California Plumbing Code 2025, section 1210.8 outlets (NFPA 54:7.7.2.1) ↗ · GoCodebook
- California Plumbing Code 2025, section 1206.3 capped outlets ↗ · GoCodebook
- Residential power vented gas water heaters: installation and use guide (gas-leak instructions) ↗ · A.O. Smith, hosted by Lowe’s
- XP Plus water heater installation and operation manual (removing a heater from a common vent) ↗ · A.O. Smith
- Energy conservation standards for consumer water heaters, final rule (orphaned furnaces) ↗ · U.S. Department of Energy, Federal Register, May 6, 2024
- DOE residential regulations explained (2029 standards) ↗ · A.O. Smith
- Cost to install a water heater (national installed ranges) ↗ · Home Depot
- How much does water heater installation cost? (updated June 17, 2026) ↗ · This Old House
- How much does it cost to upgrade an electrical panel? (updated March 31, 2026) ↗ · This Old House
- Representative average unit costs of energy (notice 2026-05899) ↗ · U.S. Department of Energy, Federal Register
- 10 CFR 430 Subpart B, Appendix E: water heater test procedure ↗ · Cornell LII
- Energy efficient home improvement credit ↗ · IRS
- 42 U.S.C. 18795a: high-efficiency electric home rebate program ↗ · Cornell LII
- Home Energy Rebates Program (status) ↗ · U.S. Department of Energy
- Water heating solutions (heat pump water heater discount) ↗ · Efficiency Maine
- Bridging the gap to heat pump adoption: water heater loaner program, final report (July 27, 2023) ↗ · Barnett Plumbing for TECH Clean California
- Emergency water heater replacement program participation agreement ↗ · Silicon Valley Clean Energy