Will your new RV furnace fit—or bring a list of changes you didn’t plan for?
The same BTU rating does not guarantee the same fit. When winter temperatures drop, unexpected installation changes can mean more time without heat. Checking compatibility before you order helps you choose the right RV furnace replacement and know what installation will involve.
Have your furnace model handy? Check your replacement options below, or read on to learn 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 your furnace label specifies a 30,000 BTU/h input rating, start by comparing replacements with the same input 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 and required installation clearances with the available cabinet space and 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. The replacement must meet both the space and airflow 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.
Find Your Furnace Replacement
Enter your current furnace model to check replacement options.
3. FOGATTI RV Furnace Replacement Compatibility Chart
The compatibility information below applies to our front-gas-inlet InstaHeat 25K, 30K and 35K furnaces.
“xx” represents model digits. Match the BTU/h input rating on your furnace label to an available replacement; the series alone does not determine capacity.
Direct Replacement
| Existing furnace series | FOGATTI replacement |
|---|---|
| Suburban SF-xxFQ | FOGATTI furnace with the same BTU/h input rating and a front gas inlet. Example: SF-30FQ → InstaHeat 30K |
| Furrion FFG xx FA | FOGATTI furnace with the same BTU/h input rating and a front gas inlet. |
Replacement With Modifications
| Existing furnace series | Required modifications |
|---|---|
| Suburban SF-xxQ | Gas connection requires modification |
| Furrion FFG xx RA | Gas connection requires modification |
| Atwood 85xx-IV | Undersized cutout requires framing modifications; gas connection also requires modification |
| Dometic DFMD Medium 25K / 30K / 35K | Undersized cutout requires framing modifications; gas connection also requires modification |
Not Compatible
| Existing furnace series | Compatibility |
|---|---|
| Suburban SH-xx | Not compatible |
| Atwood 85xxDCLP | Not compatible |
| Atwood 89xxDCLP | Not compatible |
| Atwood 89xxACLP | Not compatible |
| Dometic DFLD Large 40K | Not compatible |
| Dometic DFLA | Not compatible |
An unlisted model needs a separate fit check.
Not sure which furnace fits your RV?
Have a clear photo of your furnace label ready. A photo of the installation area can also help our team check compatibility.
Contact Us →Before You Buy
Have a qualified installer review your installation and follow the selected furnace’s installation instructions.
Find Your Fit. Get Back to Comfortable Camping.
Ready to replace your RV furnace? Explore our InstaHeat range and choose the model that matches your replacement needs.
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