Replacing an RV furnace starts with the unit you already have. Its model number and BTU rating help narrow down your options, while the installation space, ductwork, and connections determine whether a replacement will fit. Some replacements are straightforward. Others require installation changes. Here’s what to check before you buy.
1. Start With Your Existing Furnace
Find the identification label on your current furnace and note the brand, complete model number, and BTU/h input rating. Take a clear photo of the label in case you need help confirming compatibility.
If your current furnace has been heating your RV adequately, the same BTU class is usually the most practical place to start. For example, if you currently have a 30,000 BTU furnace, compare 30K replacement options before considering a higher rating. If you want to change heating capacity, have the installation and airflow requirements reviewed before purchasing.
2. Check the Installation Fit
Installation space. Compare the replacement furnace’s dimensions with both the available cabinet space and the existing installation opening. Even with the same BTU rating, a different cabinet size or layout may require changes to the opening or surrounding framing.
Ducting and return air. Check how your current furnace connects to the RV’s warm-air system. Compare the number, size, and location of ducts and the available return-air opening area with the replacement’s requirements. Physical fit alone does not guarantee compatibility. The existing ductwork and return-air setup also need to meet the replacement furnace’s requirements.
Gas, electrical, and vent connections. Check the LP gas connection and location, 12V DC power, thermostat and control connections, and combustion-air intake and exhaust arrangement against the replacement’s requirements. The gas inlet is where the propane line connects to the furnace, not one of the round warm-air duct outlets. Its location matters because the existing gas line may need modification if the replacement connection is positioned differently.
3. FOGATTI RV Furnace Replacement Compatibility Chart
Replacing a Suburban, Furrion, Atwood, or Dometic RV furnace? Check your existing series below and confirm the complete model number and BTU/h input rating on its label. In the series names below, “xx” is a placeholder for model digits.
The two tables below apply only when a corresponding FOGATTI BTU option is available. If your existing furnace’s BTU/h input rating does not match an available option, contact our support team before choosing a different capacity. Models explicitly listed as incompatible are not supported by this guide.
Direct Replacement
| Existing Furnace Series | FOGATTI Replacement |
|---|---|
| Suburban SF-xxFQ | Matching-BTU FOGATTI furnace (front gas inlet) |
| Furrion FFG xx FA | Matching-BTU FOGATTI furnace (front gas inlet) |
With the corresponding BTU rating and front gas inlet configuration, these combinations can be replaced without changes to the existing installation opening, ductwork, or gas connection. For example, a Suburban SF-30FQ can be replaced with a FOGATTI 30K RV Furnace (front gas inlet).
When Installation Changes Are Needed
Some existing furnace series can still be replaced with a FOGATTI furnace, but the installation will need to be adjusted. Have a qualified installer review the required changes before ordering.
| Existing Furnace Series | What Needs to Change |
|---|---|
| Suburban SF-xxQ | Gas connection |
| Furrion FFG xx RA | Gas connection |
| Atwood 85xx-IV | Installation opening/framing and gas connection |
| Dometic DFMD Medium 25K / 30K / 35K | Installation opening/framing and gas connection |
Some furnace series are not currently compatible with our FOGATTI replacement options, including Suburban SH-xx; Atwood 85xxDCLP, 89xxDCLP, and 89xxACLP; and Dometic DFLD Large 40K and DFLA Series. Matching the BTU rating alone does not make these models compatible. If your furnace is not listed, contact our support team with a clear photo of its identification label so we can help confirm your options.
Before You Buy
Before ordering, confirm your current model number, BTU rating, and whether the replacement can be installed directly or requires modifications. If anything is unclear, send our support team a clear photo of the old furnace label. Photos of the installation and gas connection can also help, provided these areas are safely accessible. All replacements should be installed by a qualified installer following the selected model’s installation instructions.
Upgrade Your RV Comfort With FOGATTI
Once you’ve confirmed compatibility, FOGATTI InstaHeat furnaces offer 25K, 30K, and 35K BTU options for different RV heating needs. Our furnace range includes safety and reliability features such as electronic air-pressure sensing and proportional gas control to support more reliable startup and steadier combustion. The InstaHeat 35K combines four selectable heating levels of 17K, 25K, 30K, and 35K BTU with modes for quick warm-up, everyday heating, and sleep. Its smart wired controller includes fault monitoring, helping you stay informed of heating-system faults, while a rated 40 dB Sleep mode provides a quieter setting for overnight comfort.
