{"product_id":"dometic-dfld40121-40-000-btu-lp-gas-rv-furnace","title":"Dometic DFLD40121 40,000 BTU LP Gas RV Furnace","description":"\u003cp class=\"nvn-hero\"\u003eThe Dometic DFLD40121 is a 40,000 BTU single-stage LP gas RV furnace that runs on 12-volt forced air. Its doorless, low-profile design installs horizontally or vertically, so it fits tight furnace bays while delivering strong, even heat for larger coaches and trailers.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eThe Dometic DFLD40121 is a 40,000 BTU LP gas furnace built to heat larger RVs when the temperature drops. It's a single-stage forced-air unit, so it fires at full output the moment the thermostat calls for heat and shuts off once the space is warm. That simplicity is a feature, not a shortcut. A furnace that has to work every night on the road benefits from straightforward, dependable operation, and at 40,000 BTU this one has the capacity to keep a big coach or a long trailer comfortable through cold nights and shoulder-season trips.\u003c\/p\u003e\n\u003cp\u003eWhat sets this model apart is its doorless, low-profile design. Instead of a bulky external access door, the DFLD40121 is engineered to fit compact furnace bays, and it can be installed horizontally or vertically depending on how your rig is laid out. That flexibility is a real advantage when you're replacing an older furnace or working within a tight mechanical space, because you're not forced into a single mounting orientation. The warm air discharges from the bottom into floor ducting, which is the arrangement most RV heating systems are designed around.\u003c\/p\u003e\n\u003cp\u003ePower comes from your RV's 12-volt DC system, and the furnace burns LP gas from your existing propane supply. The rear gas manifold keeps the plumbing tidy and helps the unit tuck into shallow bays. Because it's a forced-air furnace, a blower moves heated air through the duct runs whenever the burner is firing, so warmth reaches the far corners of the coach rather than pooling near the furnace. For anyone who has lived with weak or uneven heat, the difference a properly sized 40,000 BTU furnace makes on a cold morning is easy to feel.\u003c\/p\u003e\n\u003cp\u003eThe DFLD40121 measures roughly 16-1\/2 inches wide and 20 inches deep, with a low height of about 7 to 9 inches depending on the configuration, and it weighs around 40 pounds. Those dimensions let it slide into the furnace compartments used across many recreational vehicles, and the modest height is what earns the low-profile label. The wall thermostat and any access hardware are ordered separately, so you can match the control to your rig and your preferences rather than paying for parts you may already have.\u003c\/p\u003e\n\u003cp\u003eInstalling a furnace of this size deserves a careful, methodical approach. Size the 12-volt feed so the blower always has the current it needs, confirm the LP connection and the venting meet the furnace's requirements, and set the mounting orientation, horizontal or vertical, that suits your bay before you fasten anything down. Pair it with a compatible thermostat mounted where it reads the cabin temperature accurately, and you'll get steady, even heat with predictable cycles. It's the kind of job that rewards doing it right the first time, because a furnace you can trust is one you stop thinking about.\u003c\/p\u003e\n\u003cp\u003eDometic has built RV and marine climate equipment for decades, and that experience shows in a furnace engineered to fit real rigs and hold up to real use. If you're upgrading from a unit that's grown loud, weak, or unreliable, or you simply need more heating capacity for a larger coach, the DFLD40121 pairs strong 40,000 BTU output with an install-friendly, low-profile shape. Whether you're boondocking in the mountains, extending your camping season into late fall, or riding out a cold front at the marina, it's a solid, well-thought-out choice for keeping the whole rig warm. Plan the install properly and it'll deliver dependable heat for years of trips.\u003c\/p\u003e\n\u003cp\u003eThere's a lot to be said for heating capacity you don't have to think about. On the coldest morning of a trip, a furnace that comes up to temperature quickly and holds it evenly is the difference between a comfortable cabin and everyone huddling under blankets waiting for the chill to lift. The 40,000 BTU rating gives you that headroom, and the forced-air delivery makes sure the warmth actually reaches the bedroom at the back of the coach instead of stalling near the unit. Match it with clean ducting and a well-placed thermostat and it simply does its job.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003e40,000 BTU single-stage LP gas RV furnace for larger coaches and trailers\u003c\/li\u003e\n  \u003cli\u003eDoorless, low-profile design fits compact furnace bays\u003c\/li\u003e\n  \u003cli\u003eInstalls horizontally or vertically for layout flexibility\u003c\/li\u003e\n  \u003cli\u003eBottom-discharge forced air suits common RV floor ducting\u003c\/li\u003e\n  \u003cli\u003eRear gas manifold keeps plumbing tidy in shallow bays\u003c\/li\u003e\n  \u003cli\u003eRuns on 12-volt DC power and burns LP gas from your existing supply\u003c\/li\u003e\n  \u003cli\u003eBlower drives even heat to the far corners of the coach\u003c\/li\u003e\n  \u003cli\u003eCompact footprint at roughly 16.5 by 20 inches and about 40 pounds\u003c\/li\u003e\n  \u003cli\u003eWall thermostat ordered separately to match your rig\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 much heat does the DFLD40121 produce?\u003c\/summary\u003e\n    \u003cp\u003eIt's rated at 40,000 BTU, which gives it the capacity to heat larger coaches and long trailers through cold nights and shoulder-season trips.\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 a single-stage furnace. It fires at full output when the thermostat calls for heat and shuts off once the space is warm, which keeps operation simple and dependable.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan it be installed in different orientations?\u003c\/summary\u003e\n    \u003cp\u003eYes. The doorless, low-profile design can be installed horizontally or vertically, so it fits a range of furnace bays and layouts. Choose the orientation that suits your rig before fastening it down.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhich direction does the warm air discharge?\u003c\/summary\u003e\n    \u003cp\u003eIt's a bottom-discharge furnace, so warm air leaves downward into floor ducting. That matches the ductwork used in many RV heating systems.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat power and fuel does it need?\u003c\/summary\u003e\n    \u003cp\u003eIt runs on your RV's 12-volt DC system and burns LP gas from your existing propane supply. Confirm the gas connection and venting meet the furnace's requirements during installation.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes it include a thermostat?\u003c\/summary\u003e\n    \u003cp\u003eNo. The wall thermostat and any access hardware are ordered separately, so you can match the control to your rig and your preferences. Plan for those items when you order.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill it fit my furnace bay?\u003c\/summary\u003e\n    \u003cp\u003eIt measures roughly 16-1\/2 inches wide and 20 inches deep with a low height of about 7 to 9 inches depending on configuration, and weighs around 40 pounds. Always confirm your bay dimensions and ducting before installing.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhy is it called a low-profile furnace?\u003c\/summary\u003e\n    \u003cp\u003eIts doorless design and modest height let it tuck into shallow, compact furnace compartments where a taller, doored unit might not fit. The rear gas manifold also helps it sit in tight spaces.\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 DFLD40121 40,000 BTU LP Gas RV 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\u003eModel\u003c\/th\u003e\n\u003ctd\u003eDFLD40121\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e38355\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e713814220945\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eRV Furnace\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eHeat Input\u003c\/th\u003e\n\u003ctd\u003e40,000 BTU\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFuel\u003c\/th\u003e\n\u003ctd\u003eLP gas\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\u003eDischarge\u003c\/th\u003e\n\u003ctd\u003eBottom discharge\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eInstallation\u003c\/th\u003e\n\u003ctd\u003eHorizontal or vertical\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eAir Delivery\u003c\/th\u003e\n\u003ctd\u003eForced air\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eDesign\u003c\/th\u003e\n\u003ctd\u003eDoorless, low profile with rear gas manifold\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eOperating Voltage\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\u003eExternal, sold separately\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eDimensions (W x H x D)\u003c\/th\u003e\n\u003ctd\u003e16.5 in x 7 to 9 in x 20 in\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eWeight\u003c\/th\u003e\n\u003ctd\u003eApproximately 40.4 lb\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 much heat does the DFLD40121 produce?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's rated at 40,000 BTU, which gives it the capacity to heat larger coaches and long trailers through cold nights and shoulder-season trips.\"\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 a single-stage furnace. It fires at full output when the thermostat calls for heat and shuts off once the space is warm, which keeps operation simple and dependable.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Can it be installed in different orientations?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes. The doorless, low-profile design can be installed horizontally or vertically, so it fits a range of furnace bays and layouts. Choose the orientation that suits your rig before fastening it down.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Which direction does the warm air discharge?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's a bottom-discharge furnace, so warm air leaves downward into floor ducting. That matches the ductwork used in many RV heating systems.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What power and fuel does it need?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It runs on your RV's 12-volt DC system and burns LP gas from your existing propane supply. Confirm the gas connection and venting meet the furnace's requirements during installation.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does it include a thermostat?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"No. The wall thermostat and any access hardware are ordered separately, so you can match the control to your rig and your preferences. Plan for those items when you order.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Will it fit my furnace bay?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It measures roughly 16-1\/2 inches wide and 20 inches deep with a low height of about 7 to 9 inches depending on configuration, and weighs around 40 pounds. Always confirm your bay dimensions and ducting before installing.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Why is it called a low-profile furnace?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Its doorless design and modest height let it tuck into shallow, compact furnace compartments where a taller, doored unit might not fit. The rear gas manifold also helps it sit in tight spaces.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Dometic","offers":[{"title":"Default Title","offer_id":44784512794717,"sku":"2006808","price":1199.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_9f327226-f10f-4534-ba8e-58b0e9315114.png?v=1784897454","url":"https:\/\/nvnmarine.com\/products\/dometic-dfld40121-40-000-btu-lp-gas-rv-furnace","provider":"NVN Marine","version":"1.0","type":"link"}