Buying Guide
5 Best 12 Gallon RV Water Heater in 2026: A Practical RV Guide
Best 12 gallon RV water heaters compared on ignition style, electric elements and model numbers, with a clear guide to Suburban's SW12 variants.
By Hardcastle's RV Editors
10 min read5 products evaluated
A 12 gallon tank is a common upgrade for larger travel trailers and motorhomes, and Suburban dominates the category with several near-identical model numbers. This list sorts out those variants so you can tell which ignition and electric options each includes.
Each heater was compared on the model name, ignition type, electric element and relay details in its own listing, with price used as a tie-breaker between otherwise similar tanks.
Hardcastle’s RV field notes
The Rig Fit Check
A quick way to connect the shortlist to the space, workload and ownership details that matter after the box arrives.
- Start with the job
- Suburban SW12D 12-Gallon RV Water Heater leads this shortlist for Gas-only buyers. Use that fit as a reference point, then compare the alternatives against your own space and workload.
- Specs that separate the picks
- The first details to compare are 12 gallon steel tank, DSI and electric element, DSI and 12VDC relay. Confirm the exact model and included components before ordering.
- Trade-off to plan for
- No electric element included
The Practical Shortlist
A road-tested-thinking look at 5 options, organized around the job each one suits best.
Best Budget 12 Gallon
Suburban SW12D 12-Gallon RV Water Heater
Gas-only buyers
Our take Check price for Suburban SW12D 12-Gallon RV Water Heater (opens in a new tab)
Best Gas and Electric
Suburban SW12DE 12-Gallon RV Water Heater
Hookup and boondock campers
Our take Check price for Suburban SW12DE 12-Gallon RV Water Heater (opens in a new tab)
Best With 12V Relay
Suburban SW12DEL 12-Gallon RV Water Heater
Owners matching 5248A
Our take Check price for Suburban SW12DEL 12-Gallon RV Water Heater (opens in a new tab)
Best Alternate 5248A Listing
Suburban Water Heater
buyers comparing capacity, compatibility, included components and storage needs
Our take Check price for Suburban Water Heater (opens in a new tab)
Best Dark Spark Ignition
Suburban
OEM part number buyers
| Pick | Best for | Key spec | Price |
|---|---|---|---|
| Gas-only buyers | 12 gallon steel tank | Check price for Suburban SW12D 12-Gallon RV Water Heater (opens in a new tab) |
| Hookup and boondock campers | DSI and electric element | Check price for Suburban SW12DE 12-Gallon RV Water Heater (opens in a new tab) |
| Owners matching 5248A | DSI and 12VDC relay | Check price for Suburban SW12DEL 12-Gallon RV Water Heater (opens in a new tab) |
| buyers comparing capacity, compatibility, included components and storage needs | 12 gallon Suburban | Check price for Suburban Water Heater (opens in a new tab) |
| OEM part number buyers | Dark spark ignition | Check price for Suburban (opens in a new tab) |
Why Each Pick Made the Cut
Best Budget 12 Gallon1 of 5
Suburban SW12D 12-Gallon RV Water Heater on Amazon (opens in a new tab)
The strongest case for Suburban SW12D 12-Gallon RV Water Heater is direct spark ignition.
Best for
- Gas-only buyers
Why it made the shortlist
The Suburban SW12D (5246A) is a 12 gallon porcelain-lined steel tank with direct spark ignition. It has a replaceable anode rod and an optional electric element, plus a flue tube design that slows combustion for better heat transfer.
It is the lowest-priced model here at about $571 and the simplest version of the SW12 line.
Key dimensions & specs
- 12 gallon steel tank
- Direct spark ignition
- Replaceable anode rod
Pros
- Direct spark ignition
- Replaceable anode rod
- Flue tube heat transfer design
Cons
- No electric element included
- Gas-only operation
Best Gas and Electric2 of 5
Suburban SW12DE 12-Gallon RV Water Heater on Amazon (opens in a new tab)
Suburban SW12DE 12-Gallon RV Water Heater is the better fit when hookup and boondock campers.
Best for
- Hookup and boondock campers
Why it made the shortlist
The Suburban SW12DE (5247A) is a 12 gallon heater with DSI and an electric element. It uses a porcelain-lined steel tank with a replaceable anode rod.
Next to the SW12D, it adds electric heating for campsite or generator power at a higher price. It is the standard choice when you want both modes.
A great fit for travelers who camp with full hookups and also boondock. It also suits anyone who wants to save propane.
Key dimensions & specs
- DSI and electric element
- Porcelain-lined steel tank
- Replaceable anode rod
Pros
- Gas and electric in one tank
- Saves propane at full hookups
- Replaceable anode rod
- Direct spark ignition
Cons
- Electric needs 120V supply
Best With 12V Relay3 of 5
Suburban SW12DEL 12-Gallon RV Water Heater on Amazon (opens in a new tab)
Choose Suburban SW12DEL 12-Gallon RV Water Heater for 12VDC relay included.
Best for
- Owners matching 5248A
Why it made the shortlist
The Suburban SW12DEL (5248A) is a 12 gallon DSI heater with an electric element and a 12VDC relay. It keeps the porcelain-lined tank and replaceable anode of the other models.
Compared with the SW12DE, the relay supports 12V control, which matters in some RV wiring setups. It is priced a little below the SW12DE on this page.
Best for owners whose RV is wired for the relay version. It also suits anyone matching a specific model number.
Key dimensions & specs
- DSI and 12VDC relay
- Electric element
- Porcelain-lined steel tank
Pros
- 12VDC relay included
- Gas and electric operation
- Replaceable anode rod
- Direct spark ignition
Cons
- Relay version suits specific wiring
Best Alternate 5248A Listing4 of 5
Suburban Water Heater on Amazon (opens in a new tab)
Suburban Water Heater makes the shortlist because same 5248A model as the SW12DEL.
Best for
- buyers comparing capacity, compatibility, included components and storage needs
Why it made the shortlist
This Suburban 12 gallon heater with an inside 12V relay is the SW12DEL, model 5248A, sold as a single pack. The listing names the 12 gallon size and the relay directly.
It is the same model as the NKDD listing and costs slightly less. That makes it a way to buy the same heater from a different seller.
A good option for buyers who have already confirmed they need the 5248A. It also suits those shopping on price.
Key dimensions & specs
- 12 gallon Suburban
- Inside 12V relay
- Single pack 5248A
Pros
- Same 5248A model as the SW12DEL
- Inside 12V relay
- Single-pack packaging
Cons
- Sparse listing details
- Same model as another pick
Best Dark Spark Ignition5 of 5
Suburban on Amazon (opens in a new tab)
The strongest case for Suburban is three-year limited tank warranty.
Best for
- OEM part number buyers
Why it made the shortlist
The Suburban 1236.2037 is a 12 gallon gas and electric heater with dark spark ignition. The listing describes a porcelain-lined steel tank, an anode rod that protects against electrolysis, and pilot or electronic ignition.
It carries a three-year limited warranty on the tank and costs the most here. It is the OEM-style part number rather than the SW12 model name.
Best for owners who want to match an OEM part number and the tank warranty. It also suits those who prefer to buy by part.
Key dimensions & specs
- Dark spark ignition
- Gas and electric
- Three-year tank warranty
Pros
- Three-year limited tank warranty
- Gas and electric combination
- Anode rod protects the tank
- Part number matches OEM
Cons
- Listing is brief about ignition
How We Built This Shortlist
Each pick was assessed across 4 criteria weighted for real-world use.
- 12 gallon match
- Only listings naming a 12 gallon tank were included.
- Model numbers
- Suburban SW12 variants were separated by ignition and relay.
- Power options
- Electric elements and relays were compared.
- Price
- Cost across variants was noted.
What Matters Before You Choose a 12 Gallon RV Water Heater
Key buying criteria so you get the right fit the first time.
Model number decoding
Suburban labels such as D, DE and DEL mark ignition and electric options. It matters because the wrong letter means the wrong wiring. Read the model name and the listing text.
Electric element
An electric element lets you heat with shore power and save propane. It matters at full-hookup sites. Check whether the element is included or optional.
12V relay
A 12VDC relay changes how the control board is powered. It matters for RV wiring compatibility. Look for relay in the title.
Tank warranty
Warranty length covers the tank, the part most likely to fail. It matters over years. Check for a stated warranty period.
Cutout size
12 gallon tanks need space, and not all cutouts match. It matters before you order. Measure the opening.
Match a 12 Gallon RV Water Heater to Your RV
By how you power it
| Your situation | Recommended pick | Why |
|---|---|---|
| Gas only, lowest cost | Suburban SW12D | Direct spark with no electric element |
| Gas and electric | Suburban SW12DE | DSI and electric element |
| 12V relay wiring | Suburban SW12DEL | 12VDC relay included |
| Same 5248A, lower price | Suburban 5248A Single Pack | Single pack of the SW12DEL |
| OEM part and warranty | Suburban 1236.2037 | Three-year tank warranty |
Scroll sideways to see every column.
By Budget
| Budget | Recommended pick |
|---|---|
| $570 to $670 | Suburban SW12D or Suburban 5248A Single Pack |
| $690 to $740 | Suburban SW12DEL or Suburban SW12DE |
| $920 to $930 | Suburban 1236.2037 |
Gas only vs gas and electric
- Gas only
- The Suburban SW12D uses propane and costs the least.
- Gas and electric
- The Suburban SW12DE, Suburban SW12DEL, Suburban 5248A Single Pack and Suburban 1236.2037 add an electric element.
Most buyers should choose the Suburban SW12DE for flexibility.
By wiring
| Wiring | Recommended pick |
|---|---|
| Standard wiring | Suburban SW12DE |
| Relay wiring | Suburban SW12DEL |
| Match 5248A | Suburban 5248A Single Pack |
| OEM part | Suburban 1236.2037 |
For Full-Timers Specifically
- Look for
- electric element, warranty and fast recovery
- In this comparison
- The Suburban SW12DE adds electric heating and the Suburban 1236.2037 carries a three-year tank warranty.
When to Spend More
- Spend more if
- Spend more if you want warranty and OEM matching: the Suburban 1236.2037 carries a three-year limited tank warranty.
- Save if
- Save if you only need gas: the Suburban SW12D is the lowest-priced model.
Before You Bring One Home
What does the letter code mean?
D stands for direct spark ignition, E for electric element and L for the 12V relay. Confirm the exact model against your wiring.
What mistake do people make?
Ordering the wrong variant. The Suburban SW12D, SW12DE and SW12DEL look alike but differ in options.
Is the Suburban SW12DE worth it over the SW12D?
If you camp with hookups, the electric element can save propane. For gas-only use, the SW12D costs less.
How do I install a 12 gallon heater?
Shut off propane and power, drain the old tank, connect water and gas lines and test for leaks. Follow the maker's instructions.
How do I maintain it?
Replace the anode on schedule, flush sediment and inspect the burner. Winterize before freezing weather.
Bottom Line
Best overall: Suburban SW12D 12-Gallon RV Water Heater — best budget 12 gallon pick in this roundup. See the full verdicts above for every pick, with pros, cons and who each one suits.
Browse all 12 gallon rv water heater on Amazon — Prime-eligible options with current pricing.