{"product_id":"dometic-dfmdh25121-25-000-btu-lp-furnace","title":"Dometic DFMDH25121 25,000 BTU LP Gas Furnace","description":"\u003cp class=\"nvn-hero\"\u003eThe Dometic DFMDH25121 is a 25,000 BTU LP gas furnace for RVs, trailers, and small cabins. This doorless, single-stage unit uses a fan-forced blower and bottom discharge to push warm, ducted air, turning cold mornings comfortable fast.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eReliable heat is the difference between a great trip and a long, cold night. The Dometic DFMDH25121 is a 25,000 BTU LP gas furnace built to keep your rig warm without any drama. It's a single-stage, fan-forced unit that burns propane and moves heated air through your ductwork, making it a solid choice for RVs, travel trailers, fifth wheels, and compact cabins that need dependable warmth. This is the doorless configuration in Dometic's DFMD furnace family, a clean option when your sidewall vent already has a finished trim kit or you're matching an existing opening.\u003c\/p\u003e\n\u003cp\u003eThe 25,000 BTU input rating hits a practical sweet spot for mid-size coaches and trailers. It's got enough output to warm a living space quickly on a frosty morning, but it isn't so oversized that it short-cycles in a smaller floor plan. Single-stage operation keeps everything simple. The burner fires at one consistent output, the blower distributes the heat, and your thermostat handles the cycling. Fewer moving parts mean fewer things to go wrong, and that reliability is exactly what you want when you're parked somewhere far from a service center.\u003c\/p\u003e\n\u003cp\u003eAir delivery is bottom discharge driven by a fan-forced blower. The warm air exits the lower portion of the unit and feeds into your rig's ducting, so heat travels down and out to the registers instead of collecting near the furnace. That even spread keeps the far end of your coach comfortable rather than roasting the space right in front of the vent. It's a layout that works well in the floor-mounted furnace bays common to RVs and trailers.\u003c\/p\u003e\n\u003cp\u003eThis furnace uses a sealed combustion chamber, so the air it burns comes from outside and the exhaust goes back outside. That separation keeps combustion completely isolated from your living space, and the air you feel indoors stays clean, forced heat. Direct spark ignition lights the burner automatically each time the thermostat calls for heat, which means there's no standing pilot to relight and no fuel wasted between cycles. You just set the temperature and forget about it.\u003c\/p\u003e\n\u003cp\u003eSafety features are layered into the design. A sail switch confirms the blower is actually moving air before the burner fires, and a high-limit switch shuts the burner down if temperatures ever climb past the safe range. The unit runs on 12V DC and draws roughly 7.5 amps while operating, so it's easy on your house battery. It's also compatible with standard 12-volt RV thermostats, which means in many installations you can keep the controls you already have and drop this furnace right in.\u003c\/p\u003e\n\u003cp\u003ePhysically, the DFMDH25121 is built for common furnace bays. It measures about 16.5 inches wide, 7 inches tall, and 20 inches deep, and weighs around 34 pounds, so a single installer can maneuver it into place. If you're replacing an aging unit, that compact footprint and ducted, bottom-discharge design make it a natural fit for a lot of existing setups. And because it's the doorless version, you won't be paying for an exterior door you don't need.\u003c\/p\u003e\n\u003cp\u003eDometic has spent decades building comfort and climate equipment for the mobile lifestyle, and that experience shows in how this furnace is engineered. It's a component you install once and stop thinking about. If you want the same 25,000 BTU output with an exterior access door, the DFMDH25111 covers that, and the DFMDH30121 steps up to 30,000 BTU for larger coaches. But for a lot of RVers matching an existing opening, this doorless 25,000 BTU model is the practical, no-fuss pick. Connect it to your LP supply and ductwork, set your thermostat, and enjoy steady propane heat trip after trip. Whether you're chasing shoulder-season camping, living in your rig full-time, or just want dependable warmth on the occasional cold snap, this furnace is ready to deliver.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003e25,000 BTU input rating for mid-size RVs, trailers, and compact cabins\u003c\/li\u003e\n  \u003cli\u003eDoorless configuration for clean matching of existing sidewall openings\u003c\/li\u003e\n  \u003cli\u003eSingle-stage LP gas operation for simple, reliable heating\u003c\/li\u003e\n  \u003cli\u003eFan-forced blower with bottom discharge for even, ducted air distribution\u003c\/li\u003e\n  \u003cli\u003eSealed combustion chamber keeps burn air and exhaust separate from living space\u003c\/li\u003e\n  \u003cli\u003eDirect spark ignition, no standing pilot to relight\u003c\/li\u003e\n  \u003cli\u003eSail switch and high-limit switch for layered safety\u003c\/li\u003e\n  \u003cli\u003e12V DC operation drawing about 7.5 amps, easy on the house battery\u003c\/li\u003e\n  \u003cli\u003eCompatible with standard 12-volt RV thermostats\u003c\/li\u003e\n  \u003cli\u003eCompact 16.5 x 7 x 20 inch body weighing roughly 34 pounds\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Dometic reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow many BTUs does the DFMDH25121 put out?\u003c\/summary\u003e\n    \u003cp\u003eIt's rated at 25,000 BTU input, a strong match for mid-size RVs, travel trailers, fifth wheels, and small cabins. That's enough to warm a space quickly without being oversized for a smaller floor plan.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat's the difference between the DFMDH25121 and the DFMDH25111?\u003c\/summary\u003e\n    \u003cp\u003eBoth are 25,000 BTU single-stage bottom-discharge furnaces. The DFMDH25121 is the doorless configuration, while the DFMDH25111 includes an exterior access door. Choose the doorless version when you're matching an existing opening or trim kit.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat fuel does this furnace use?\u003c\/summary\u003e\n    \u003cp\u003eThe DFMDH25121 runs on LP gas, also known as propane. It draws combustion air from outside through its sealed chamber and vents exhaust back outside, so the heated air circulating indoors stays clean forced air.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this a single-stage or two-stage furnace?\u003c\/summary\u003e\n    \u003cp\u003eIt's single-stage. The burner fires at one consistent output and the thermostat cycles it on and off to hold your set temperature. That simplicity translates to fewer parts and dependable performance.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat does bottom discharge mean for installation?\u003c\/summary\u003e\n    \u003cp\u003eBottom discharge means the warm air exits the lower portion of the unit, which suits floor-mounted furnace bays where heated air feeds down into ducted runs. It's a common layout in RV and trailer installations.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow much power does it draw and what does it run on?\u003c\/summary\u003e\n    \u003cp\u003eThe furnace operates on 12V DC and pulls roughly 7.5 amps while running. It works with standard 12-volt RV thermostats, so in many cases you can keep the controls you already have installed.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat are the dimensions and weight?\u003c\/summary\u003e\n    \u003cp\u003eIt measures about 16.5 inches wide, 7 inches tall, and 20 inches deep, and weighs around 34 pounds. That compact footprint fits many existing furnace bays and lets one person handle the install.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat safety features does it include?\u003c\/summary\u003e\n    \u003cp\u003eA sail switch confirms the blower is moving air before the burner lights, and a high-limit switch shuts the burner down if temperatures climb too high. Direct spark ignition also means there's no standing pilot flame to manage.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eDometic DFMDH25121 25,000 BTU LP Gas Furnace\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eDometic\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003eDFMDH25121\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e713814220419\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eRV LP Gas Furnace\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBTU Input Rating\u003c\/th\u003e\n\u003ctd\u003e25,000 BTU\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFuel Type\u003c\/th\u003e\n\u003ctd\u003eLP Gas (Propane)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eStage\u003c\/th\u003e\n\u003ctd\u003eSingle Stage\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eAir Discharge\u003c\/th\u003e\n\u003ctd\u003eBottom Discharge\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eAir Delivery\u003c\/th\u003e\n\u003ctd\u003eFan-Forced Blower\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eIgnition\u003c\/th\u003e\n\u003ctd\u003eDirect Spark\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCombustion\u003c\/th\u003e\n\u003ctd\u003eSealed Combustion Chamber\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePower\u003c\/th\u003e\n\u003ctd\u003e12V DC, approximately 7.5 amps\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eThermostat\u003c\/th\u003e\n\u003ctd\u003eStandard 12-volt RV thermostat compatible\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSafety Controls\u003c\/th\u003e\n\u003ctd\u003eSail switch and high-limit switch\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eDoor Variant\u003c\/th\u003e\n\u003ctd\u003eDoorless configuration\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eDimensions\u003c\/th\u003e\n\u003ctd\u003e16.5 in W x 7 in H x 20 in D\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eWeight\u003c\/th\u003e\n\u003ctd\u003eApproximately 34 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How many BTUs does the DFMDH25121 put out?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's rated at 25,000 BTU input, a strong match for mid-size RVs, travel trailers, fifth wheels, and small cabins. That's enough to warm a space quickly without being oversized for a smaller floor plan.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What's the difference between the DFMDH25121 and the DFMDH25111?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Both are 25,000 BTU single-stage bottom-discharge furnaces. The DFMDH25121 is the doorless configuration, while the DFMDH25111 includes an exterior access door. Choose the doorless version when you're matching an existing opening or trim kit.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What fuel does this furnace use?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The DFMDH25121 runs on LP gas, also known as propane. It draws combustion air from outside through its sealed chamber and vents exhaust back outside, so the heated air circulating indoors stays clean forced air.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is this a single-stage or two-stage furnace?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's single-stage. The burner fires at one consistent output and the thermostat cycles it on and off to hold your set temperature. That simplicity translates to fewer parts and dependable performance.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What does bottom discharge mean for installation?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Bottom discharge means the warm air exits the lower portion of the unit, which suits floor-mounted furnace bays where heated air feeds down into ducted runs. It's a common layout in RV and trailer installations.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How much power does it draw and what does it run on?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The furnace operates on 12V DC and pulls roughly 7.5 amps while running. It works with standard 12-volt RV thermostats, so in many cases you can keep the controls you already have installed.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What are the dimensions and weight?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It measures about 16.5 inches wide, 7 inches tall, and 20 inches deep, and weighs around 34 pounds. That compact footprint fits many existing furnace bays and lets one person handle the install.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What safety features does it include?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"A sail switch confirms the blower is moving air before the burner lights, and a high-limit switch shuts the burner down if temperatures climb too high. Direct spark ignition also means there's no standing pilot flame to manage.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Dometic","offers":[{"title":"Default Title","offer_id":44782637711453,"sku":"2006770","price":1187.49,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_17a8133d-8cc5-404f-9445-37b91b5ea719.png?v=1784854106","url":"https:\/\/nvnmarine.com\/products\/dometic-dfmdh25121-25-000-btu-lp-furnace","provider":"NVN Marine","version":"1.0","type":"link"}