Home / Heat, air, shore power and propane
Heat, air, shore power and propane
A first comparison for the 16 ft × 8 ft draft trailer. These are separate systems. Do not buy or cut holes until the structure and floor plan are settled.
Words used here
- BTU/h
- British thermal units per hour (BTU/h) measure heating or cooling output.
- LP gas
- Liquefied petroleum (LP) gas is propane stored as liquid in a cylinder.
- CO alarm
- A carbon monoxide (CO) alarm warns of a poisonous, odorless combustion gas.
- TT-30
- Travel-trailer 30 amp (TT-30) is the common three-prong, 120 V campground connection.
- Converter/charger
- A converter/charger makes 12 V direct current (DC) and charges the battery from 120 V alternating current (AC).
Indoor heat
| Option | Size, 12 V draw and weight | Cutout / fuel / exhaust | Current listing, 2026-10-11 |
|---|---|---|---|
| Dometic / former Atwood DF12 | 12,000 BTU/h; 12 V; 20.8 lb spec | 20 × 12 × 7 in body. The exact wall opening and the sealed intake/exhaust fitting come from its installation manual. manual | $1,297.99 Dometic listing store |
| Suburban SF-FQ | 20,000 BTU/h; 5.1 A at 12 V; 29 lb spec | 7.5 × 17 × 20 in body. It is a forced-air, sealed-combustion furnace: mount the specified exterior intake/exhaust door and keep its clearances. manual | Price: no current listing source found. |
| Propex HS2000 | About 6,500 BTU/h; 12 V fan; protect with its specified 5 A fuse. Weight: no source found. manual | Small propane heater with separate combustion intake and exhaust through the floor. Follow the maker's hose, exhaust and clearance instructions. manual | Price: no current listing source found. |
| Webasto Air Top 2000 STC diesel | 3,100–7,000 BTU/h; 1.25–2.45 A at 12 V; 5.73 lb spec | Needs a separate diesel tank, fuel line, combustion-air intake and hot exhaust outside. It burns 0.03–0.06 gal/h. spec | Price: no current listing source found. |
| VEVOR-type 2 kW diesel import | 2 kW (about 6,800 BTU/h); 12 V. Weight and running amps: no reliable maker source found. listing | Usually includes a 10 L / 2.6 gal tank. It still needs an outside exhaust, intake and a leak-free fuel route. listing | $103.99 listing store |
Starting comparison: A propane forced-air furnace is the familiar RV answer and can heat the whole cabin through ducts. It is heavy and needs an exterior wall opening. The Webasto is light and economical but adds a second fuel and a hot exhaust. The cheap diesel option saves money but has weak documentation. Claude's starting pick: compare the smaller sealed-combustion propane furnace first; it uses the same propane system as the water heater.
There is no sourced heat-loss rule of thumb found for this exact 16 ft × 8 ft insulated trailer at 20 °F. Do not turn the furnace BTU rating into a promise of comfort. Insulation, air leaks, windows, wind and desired indoor temperature control the real load.
Mr. Heater's Buddy manual says “do not operate the heater while sleeping” and requires at least 9 sq in of ventilation. It puts combustion products and moisture into the room. That makes it an attended, temporary heater, not the trailer's night heat. owner's manual
Air conditioning
| Option | Weight, roof opening and running load | Start / generator | Current listing, 2026-10-11 |
|---|---|---|---|
| Dometic Brisk II 13,500 BTU/h | 72 lb net / 74 lb installed; standard 14 × 14 in roof opening; compressor 13.2 A plus fan 2.7 A. spec | Starting amps: check the unit nameplate; no start-surge source found. With a soft starter, use at least a 2,000 W continuous generator for a 13,500 BTU unit. sizing guide | $908.99 upper unit store |
| Coleman Mach 15, 15,000 BTU/h | About 79.5 lb upper unit; 15.4 A full-load cooling in the published specification. Roof opening: verify the exact install manual; no source found in the product page. spec sheet | 63 locked-rotor amps in the published specification. With a soft starter, use at least 2,500 W continuous; 15,000 BTU units can draw 16.2 A on a hot day. sizing guide | Price: no current listing source found. |
| Furrion Chill 15,000 BTU/h | 15.8 A / 1,730 W; current Furrion units fit a 14 × 14 in roof cutout. Weight: no source found. maker FAQ | Furrion told a retailer 30 A and 2,500 starting W. Treat that as a starting point, then use the exact nameplate. retailer report | Price: no current listing source found. |
| 120 V mini-split | Some 9,000 BTU models are 8–12 A; weight and price vary by paired indoor/outdoor unit. range | Needs a wall penetration, refrigerant lines, outdoor condenser mount and proper electrical circuit. No roof hole, but more fabrication and service work. | Price: no current listing source found. |
| 5,000 BTU window unit | About 400–550 running W; exact weight and amps are model-specific. efficiency guide | Needs a framed, weather-sealed wall opening and a way to remove or protect it in travel. It is cheap and light compared with a rooftop unit. | Price: no current listing source found. |
A Micro-Air EasyStart Breeze is $345 current listing and claims up to 75% lower startup current. It helps a generator start an air conditioner; it does not lower the air conditioner's running power. listing
Battery answer: no. A 100 Ah, 12.8 V battery stores 1,280 Wh. A 1,000 W inverter cannot supply a 1,536–1,944 W rooftop running load (13.5k: 15 A × 120 V; 15k: 16.2 A × 120 V). load math Even a 500 W window unit would use 500 Wh per hour before inverter loss: only about 2.6 hours from 1,280 Wh, before protecting battery reserve. A soft starter cannot change either limit.
Shore power
A 30 A TT-30 service is 120 V × 30 A = 3,600 W, not 240 V. TT-30 listing Put a weatherproof 30 A inlet on the exterior. Run it to a main breaker panel with a 30 A main. Add a listed converter/charger, such as WFCO 8735, or an inverter/charger. If an inverter can feed the AC panel, add a listed transfer switch so shore and inverter power can never meet. transfer-switch guide
| Breaker / source | Loads | Use from a 15/20 A household adapter |
|---|---|---|
| 30 A main | Inlet, panel and transfer switch. | The adapter limits the whole trailer to the house outlet breaker. Do not treat it as 30 A. adapter |
| 15 A branch | General receptacles, battery charger and small loads. | Usually battery charging, lights, fridge and one small appliance can run if their combined nameplate load stays below the outlet breaker. |
| 20 A dedicated branch | Rooftop air conditioner. | Do not run the rooftop air conditioner plus other large loads on a 15/20 A household outlet. Its running draw alone is about 15–16.2 A. load guide |
Propane system and alarms
Use two DOT (U.S. Department of Transportation) cylinders on a tongue tray: either two 20 lb cylinders to save weight, or two 30 lb cylinders for longer stays. Use a two-stage automatic-changeover regulator. Its low-pressure outlet feeds the furnace and water heater through approved LP piping. Add a separate exterior low-pressure quick-connect only for the portable outside stove. Cylinder, regulator, hose and appliance instructions control the exact fittings and pressure.
After every cylinder, regulator or appliance connection change, close appliance valves, pressurize the system, and leak-test every joint with an approved leak-test liquid. Never use a flame. Propane Education & Research Council safety guide
| Required protection | What to install | Why |
|---|---|---|
| LP gas alarm | Listed RV propane alarm, mounted and powered exactly as its instructions say. | NFPA 1192 is the RV fire and life-safety standard used by RVIA; an RV build should follow its LP-gas detector provisions. Exact edition text: no free primary source found. RVIA standards |
| CO alarm | Listed RV-suitable CO alarm near sleeping areas. | NFPA 1192 calls for a listed CO alarm. NFPA CO safety |
| Smoke alarm | Listed smoke alarm, high on wall or ceiling and away from cooking false alarms. | NFPA advises at least 10 ft from cooking appliances. NFPA placement |
One 20 lb cylinder runtime: propane has about 91,500 BTU per gallon. source A 20 lb cylinder holds about 4.7 gallons when filled to its normal limit. source 4.7 × 91,500 = 430,050 BTU. At a 12,000 BTU/h furnace input, 430,050 ÷ 12,000 = about 35.8 hours of continuous full fire. At 20,000 BTU/h, it is about 21.5 hours. Real runtime is longer when the thermostat cycles and shorter if other propane appliances run.
Design numbers for my trailer
| Item | Number | Source |
|---|---|---|
| Draft cabin | 16 ft × 8 ft | Working brief; heat-loss rule at 20 °F: no source found. |
| Furnace comparison | 12,000 / 20,000 BTU/h propane; 7,000 BTU/h diesel | Dometic; Suburban; Webasto |
| Rooftop opening | 14 × 14 in class | Dometic |
| Rooftop weight | 74 lb Brisk II; about 79.5 lb Mach 15 upper unit | Dometic; Coleman sheet |
| Rooftop running load | About 1,800 W for 13.5k; 1,944 W for 15k | Micro-Air |
| Smallest generator with soft starter | 2,000 W continuous for 13.5k; 2,500 W continuous for 15k | Micro-Air |
| Existing battery / inverter | 1,280 Wh battery; 1,000 W inverter; cannot run rooftop AC | 100 Ah × 12.8 V arithmetic; rooftop load source |
| Shore service | TT-30, 120 V, 30 A, 3,600 W | WEN |
| Propane storage | Two 20 lb or two 30 lb DOT cylinders on tongue | Design choice; size and restraint details must follow the cylinder and RV standard instructions. |
| 20 lb cylinder furnace runtime | About 35.8 h at 12,000 BTU/h; 21.5 h at 20,000 BTU/h | 91,500 BTU/gal; 4.7 gal |