{"product_id":"dometic-dfmdh30121-30-000-btu-lp-furnace","title":"Dometic DFMDH30121 30,000 BTU LP Gas Furnace","description":"\u003cp class=\"nvn-hero\"\u003eThe Dometic DFMDH30121 is a 30,000 BTU LP gas furnace built for larger RVs, fifth wheels, and coaches. Single-stage operation and a fan-forced blower push warm, ducted air out the bottom discharge, so even a big floor plan heats up fast on a cold night.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eBig rigs need big heat. The Dometic DFMDH30121 is a 30,000 BTU LP gas furnace built for exactly that job. It's the higher-output member of Dometic's DFMD furnace family, and it's designed to warm larger RVs, fifth wheels, toy haulers, and full-size coaches where a smaller unit would struggle to keep up. If your rig has a long floor plan or you camp where winters bite, this is the furnace that keeps every corner comfortable.\u003c\/p\u003e\n\u003cp\u003eThe 30,000 BTU input rating is the headline here. That extra output over the 25,000 BTU models in the same line gives you faster recovery on a frigid morning and more capacity to fight heat loss through big slide-outs and large windows. It's single-stage, so the burner fires at one consistent output and your thermostat cycles it to hold your set temperature. That approach keeps the design simple and dependable, which is exactly what you want from a heat source when you're parked somewhere remote and the temperature is dropping.\u003c\/p\u003e\n\u003cp\u003eAir delivery is bottom discharge with a fan-forced blower. The warm air exits the lower portion of the unit and feeds into your rig's ductwork, so heat travels down and out to the registers instead of pooling near the furnace. That's how you get even warmth from front to back rather than one hot spot and a cold bedroom. In a larger coach, that even distribution really matters, and the DFMDH30121 has the airflow to back it up.\u003c\/p\u003e\n\u003cp\u003eLike the rest of the DFMD line, this furnace uses a sealed combustion chamber. It pulls the air it burns from outside and sends exhaust back outside, keeping combustion completely separate from your living space. The air you feel indoors is clean, forced heat. Direct spark ignition lights the burner automatically every time the thermostat calls for heat, so there's no standing pilot to babysit and no fuel wasted between cycles. It's the kind of modern, hands-off operation you don't have to think about.\u003c\/p\u003e\n\u003cp\u003eSafety is layered in. A sail switch verifies the blower is moving air before the burner ever lights, and a high-limit switch cuts the burner if temperatures rise past the safe range. The furnace runs on 12V DC and works with standard 12-volt RV thermostats, so in many installations you can keep the controls you already have. That makes it a straightforward upgrade path if you're replacing a tired unit and stepping up to more heating capacity at the same time.\u003c\/p\u003e\n\u003cp\u003eThis is the DFMDH30121, the doorless configuration, which is a clean choice when your sidewall vent already has a finished trim kit or you're matching an existing opening. Physically it shares the compact, drop-in friendly footprint of the family, so it fits common furnace bays and a single installer can handle placement. If you're comparing options, the 25,000 BTU DFMDH25111 and DFMDH25121 cover smaller and mid-size rigs, while this 30,000 BTU model is the pick when you need maximum ducted output.\u003c\/p\u003e\n\u003cp\u003eDometic has spent decades building comfort systems for life on the road, and it shows in how this furnace is engineered and assembled. It's a component you install once and rely on for years, which is exactly what you're after when reliable heat is the difference between a great trip and a miserable one. For big coaches, cold-weather camping, and full-time living, the DFMDH30121 delivers the steady, powerful propane heat you can count on. Connect it to your LP supply and ductwork, set your thermostat, and let it do the work while you enjoy the season. It's built to run quietly in the background, morning after morning, so the only thing you'll notice is that your rig is warm when you wake up, no matter how hard the wind is blowing outside.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003e30,000 BTU input rating for larger RVs, fifth wheels, and full-size coaches\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\u003eHigher output than the 25,000 BTU models for faster cold-morning recovery\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 compatible with standard 12-volt RV thermostats\u003c\/li\u003e\n  \u003cli\u003eDoorless configuration for clean matching of existing sidewall openings\u003c\/li\u003e\n  \u003cli\u003eCompact, drop-in friendly body for common furnace bays\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 DFMDH30121 put out?\u003c\/summary\u003e\n    \u003cp\u003eIt's rated at 30,000 BTU input, the highest output in Dometic's DFMD furnace family. That extra capacity makes it a strong match for larger RVs, fifth wheels, toy haulers, and full-size coaches with long floor plans.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat fuel does this furnace use?\u003c\/summary\u003e\n    \u003cp\u003eThe DFMDH30121 runs on LP gas, also known as propane. It pulls 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 your thermostat cycles it on and off to hold the set temperature. Fewer moving parts means dependable, no-drama performance.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhy choose the 30,000 BTU model over a 25,000 BTU one?\u003c\/summary\u003e\n    \u003cp\u003eThe higher output gives you faster recovery on cold mornings and more capacity to overcome heat loss through large slide-outs and windows. It's the right pick for bigger coaches or camping in genuinely cold weather.\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\u003eWhat power does it need and what thermostat works with it?\u003c\/summary\u003e\n    \u003cp\u003eThe furnace runs on 12V DC and works with standard 12-volt RV thermostats. In many installations you can keep the controls you already have, which makes it a straightforward upgrade.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow does the DFMDH30121 differ from the 25,000 BTU models?\u003c\/summary\u003e\n    \u003cp\u003eThis is the 30,000 BTU, doorless configuration for maximum ducted output. The DFMDH25111 and DFMDH25121 are 25,000 BTU single-stage bottom-discharge units for smaller and mid-size rigs.\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 DFMDH30121 30,000 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\u003eDFMDH30121\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e0713814220471\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\u003e30,000 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\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  \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 DFMDH30121 put out?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's rated at 30,000 BTU input, the highest output in Dometic's DFMD furnace family. That extra capacity makes it a strong match for larger RVs, fifth wheels, toy haulers, and full-size coaches with long floor plans.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What fuel does this furnace use?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The DFMDH30121 runs on LP gas, also known as propane. It pulls 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 your thermostat cycles it on and off to hold the set temperature. Fewer moving parts means dependable, no-drama performance.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Why choose the 30,000 BTU model over a 25,000 BTU one?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The higher output gives you faster recovery on cold mornings and more capacity to overcome heat loss through large slide-outs and windows. It's the right pick for bigger coaches or camping in genuinely cold weather.\"\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\": \"What power does it need and what thermostat works with it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The furnace runs on 12V DC and works with standard 12-volt RV thermostats. In many installations you can keep the controls you already have, which makes it a straightforward upgrade.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How does the DFMDH30121 differ from the 25,000 BTU models?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"This is the 30,000 BTU, doorless configuration for maximum ducted output. The DFMDH25111 and DFMDH25121 are 25,000 BTU single-stage bottom-discharge units for smaller and mid-size rigs.\"\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. 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