This is a diesel-powered forced air heater that puts out 1.4 to 5kW (4,700 to 17,000 BTU). It suits campervans, tents, garages, workshops and greenhouses. The manufacturer says it covers 25 square metres and works in temperatures from -40°C to 40°C.
What does it cost to run? Fuel use is 0.18 to 0.53 L/h. In a manufacturer test, the Diesel air heater 5kW raised the temperature inside a tent from 0°C to 20°C in about 8 minutes. It runs from 12V or 24V and includes a 220-240V transformer for UK sockets.
The body measures 34.5 x 15.7 x 39 cm and has an LCD controller. You also get a pre-paired remote, a 24-hour timer, a 3.5 L tank and a threaded fuel cap that cuts spills. Overheat protection is built in.
Heat output and warm-up - The heater gives 1.4 to 5kW, which is 4,700 to 17,000 BTU. Why does the range matter? You can run it low to save fuel or high to warm a cold space quickly. The manufacturer's tent test took 0°C to 20°C in about 8 minutes. One garage owner saw -2°C outside and 17°C inside after an hour.
Low fuel use - It burns 0.18 to 0.53 L/h of diesel. At the top setting, a full 3.5 L tank lasts roughly 6.6 hours. On the lowest setting it lasts around 19 hours. That makes it practical for overnight use in a van or cabin without constant refuelling.
Three power options - It runs from 12V or 24V, so you can use a leisure battery or vehicle supply. A 220-240V transformer is included for mains use. Is that useful? Yes. You can use the same heater in a van on the road and in a shed or garage at home.
24-hour timer - The upgraded T3 controller lets you set heating times in advance. What does that mean in practice? The van can be warm before you wake up. A workshop can be warm before you start work. Note that the 5 L models in the same range do not have this timer.
Remote control and LCD - The pre-paired remote works from up to 30 m away. It has four buttons for on, off, plus and minus. One reviewer runs theirs from inside their house to heat a log cabin. You can set power anywhere from 1.4 to 5kW without leaving the sofa.
Compact all-in-one body - It measures 34.5 x 15.7 x 39 cm and weighs 12.4kg gross. The integrated build means fewer parts to fit. The kit has the installation components, a printed manual and QR-code guidance. The exhaust must go outdoors away from windows and air intakes. Do not use it in enclosed sleeping areas.
The N4 gives out 1,400 to 5,000 W of thermal power. That is 4,700 to 17,000 BTU. The listed heating coverage is 25 square metres.
Does that work in real use? One buyer fitted it in an uninsulated 3 x 6 metre garage (18 square metres). The outside temperature was 15°C and the empty garage was 17°C. After one hour the garage was 23°C and they had to turn the power down. Another buyer ran it in a log cabin and held 17 to 20°C in freezing weather.
In the maker's test it raised the air inside a tent from 0°C to 20°C in about 8 minutes. Test conditions are not the same as a draughty garage though. A reviewer started with -2°C outside. Their garage reached 10°C in half an hour and 17°C after an hour.
The heater itself works in outside temperatures from -40°C to 40°C. You can set the target between 10°C and 35°C.
Fuel use is 0.18 to 0.53 litres per hour. The tank holds 3.5 litres. Do the sums and you get roughly 19 hours on the lowest setting. On full power it is about 6.5 hours.
Real use will vary with the heat level you pick. One owner ran theirs up to 12 hours a day through a whole winter. They described it as reliable with no soot in the exhaust. The tank has an internally threaded cap that seals the tank and cuts down on spills when you move the unit.
It takes 12 V or 24 V DC. It also comes with a 220 to 240 V transformer for standard UK sockets. So you can use it in a campervan on a leisure battery or plug it in at home. A garage, shed or workshop with a socket is fine.
One buyer reported it drew under 70 watts while running. That is the electrical draw of the fan and pump. The heat comes from the diesel.
The kit has an LCD controller and a pre-paired remote. The remote works from up to 30 m away. It has four buttons: on, off, plus and minus. The plus and minus buttons adjust power from 1.4 to 5 kW. One owner said it worked from inside their house to reach a log cabin.
The upgraded T3 controller has a 24-hour timer. You can set a start time so the campervan is warm before you wake up. You can also pre-heat a workshop before you start work. There is no thermostat on this model though. You set the power level yourself.
The listed uses are garage, greenhouse, home, patio, tent, warehouse and workshop. It is a floor-mount unit that measures 39 x 15.7 x 34.5 cm. The gross weight is 12.4kg. The item weight on the page is 16 lb (about 7.3kg).
The exhaust carries combustion gases. So the outlet must go outdoors and away from windows and air intakes. Fit the muffler horizontally with the small hole facing down. Do not use it in enclosed sleeping areas. The exhaust pipe gets very hot. Keep it away from anything that burns and shield it from people. One buyer stood the legs on blocks of wood to lift the exhaust off the surface. Another suggested not extending the exhaust pipe far or routing it upwards. Both can upset combustion.
Opinions on noise are mixed. Of 12 mentions in reviews, 8 were positive and 4 negative. The pump ticks while it primes. After that, several owners called it quiet. One said it was a little noisy but manageable. The maker says upgraded internal parts reduce operating noise.
Some faults appear in reviews. One buyer had an E1 error code and fixed it after contacting customer service. Another got an E03 code after 11 months and could not restart it. A third found the fuel line between the pump and the chamber began to drip slightly after a year. That owner replaced it. Another buyer saw an error at first start. A restart cleared it. They put it down to air in the fuel line. The heater has a 1 year warranty and Amazon allows 30-day returns on many products.
The N4 is the slim model. It has a 3.5 L tank and a timer. The N2 is wider with a 5 L tank but has no timer. A reviewer pointed this out. You need to decide which matters more to you.
The N4 is rated to 1,500 m altitude. The N2E, N3 and N2pro are plateau models rated to 5,200 m. They also use a Japanese-branded glow plug. The N3 and N2pro add a thermostat and a silent oil pump. The N4 has a standard glow plug and oil pump. For most UK campsites and garages 1,500 m is plenty.
The kit includes the essential installation parts and a printed manual. There is also QR-code guidance and an assembly video. The all-in-one body has fewer parts to join than a split heater. A buyer said you fit the hoses and add diesel. Then you press the remote to start.
Some buyers did buy extra bits. One needed extra tubing and connectors (22 mm male and 24 mm female) plus wrap-around insulation to route the exhaust away from a door. Another said the hardest job was drilling the exhaust hole through the wall. A German buyer found the manual lacked some warnings and fitted an air filter on the intake to keep workshop dust out. The components include a multi-pulse oil pump and a high quality glow plug.
The LF Bros N4 is a diesel air heater in a single white housing. It is sold as an all-in-one parking heater and runs on 12V or 24V DC. It also comes with a transformer for 220-240V UK sockets. It has a thermal power range of 1,400-5,000 W and a heat output of 4,700-17,000 BTU. Fuel consumption is 0.18-0.53 L/h. The brand lists it for campervans, tents, garages, workshops, warehouses, greenhouses, patios and homes. It is rated to heat an area of 25 square metres.
Under test conditions the heater raised the temperature inside a tent from 0°C to 20°C in about 8 minutes. The working temperature range is -40°C to 40°C. The temperature setting runs from 10°C to 35°C. The N4 has no thermostat. Power can be changed between 1.4 kW and 5 kW with the plus and minus buttons on the remote.
Reviewers give some real-world figures. One reviewer fitted it in an uninsulated garage measuring 3 x 6 metres. The outside temperature was 15°C and the empty garage was 17°C. After one hour the garage was 23°C. Another reviewer started it with -2°C outside. The garage reached 10°C within half an hour and 17°C after an hour. A third reviewer heats a log cabin to 17-20°C in freezing weather and usually runs it at 2 kW. A German reviewer warmed a room from 1°C to 13°C in about 30 minutes on the highest setting. Later that reviewer used it for at least 3 hours a day in a workshop for 4 weeks and had no starting problems.
The heater accepts 12V and 24V DC. The included transformer allows mains use at 220-240V AC. The amperage is listed as 15 A. The page lists the voltage as 12 V in one place and 12V/24V/230V in the model comparison. One reviewer said it draws less than 70 watts. The N4 has a 24-hour programmable timer through its upgraded T3 controller. You can set heating times ahead. For example you can warm a campervan before you wake or pre-heat a workspace before work. The LCD controller and the pre-paired remote both control the heater. The remote works from up to 30 m away and has four buttons (On/Off/+/-). One reviewer said it works from inside their house.
The heater measures 39 cm deep by 15.7 cm wide by 34.5 cm high. It is tall and narrow. The page gives the item weight as 16 pounds, which is about 7.26kg. The gross weight is 12.4kg. The gross figure probably includes packaging and accessories. The heater stands on legs and mounts on the floor. One reviewer screwed the legs onto blocks of wood to keep the hot exhaust away from the surface below. That reviewer said longer legs would help.
The fuel tank holds 3.5 L. The fuel cap is internally threaded. LF Bros says this seals the tank better and reduces spills during transport. At the highest consumption of 0.53 L/h a full tank would last about 6.6 hours. At the lowest consumption of 0.18 L/h it would last about 19 hours. These run times are worked out from the stated figures and are not LF Bros claims. One reviewer ran the heater for up to 12 hours a day through a winter. That reviewer later found a very slight diesel drip from the fuel line between the pump and the combustion chamber and replaced the line.
The kit includes the main installation parts and a printed manual. It also has QR-code guidance and an assembly video. Reviewers found it easy to fit. Steps include fitting the hoses and adding diesel. Then you press the remote to start. The hardest job for one reviewer was drilling a hole for the exhaust. Another reviewer bought extra tubing and connectors (22 mm male and 24 mm female) plus wrap-around insulation to route the exhaust away from an outside door. The pump ticks while it primes at the start. One reviewer got an error on first start. They restarted it and it ran normally. The reviewer thought air was still in the fuel line.
The exhaust gas contains combustion gases. The exhaust outlet must be outdoors and placed so the gases disperse safely. The muffler must be fitted horizontally with its small hole facing down. Route the exhaust away from windows and air intakes. Do not use the heater in an enclosed sleeping area. A German reviewer added these points that the manual lacks:
That reviewer also fitted an air filter on the combustion air intake to keep out dust from woodworking. One reviewer built a wooden box and put the heater outside for safety. Another fitted it in a custom enclosure with air in and hot air out through a log cabin wall.
LF Bros says upgraded internal components reduce noise. Reviewers disagree. Some call the heater and fuel pump quiet. Others call it a little noisy. A French reviewer said the flame noise is fairly loud and the pump is noisy at first while it is empty. One reviewer found it quiet enough without fitting the muffler.
Two reviewers reported error codes. One saw E1 after a few days and LF Bros customer service helped to get it running again. Another reviewer saw what they thought was E03 after 11 months and could not start the heater. Another reviewer had a unit stolen and received a replacement the next day after calling customer service. The warranty is 1 year.
The N4 is one of five sizes listed on the page. The N4 costs £219.98 and has a 3.5 L tank and a timer. It is not a plateau model and its altitude limit is 1,500 m. The N2 costs £205.98 and has a 5 L tank but no timer. The N2E costs £305.98 and has a 5 L tank and a timer. It has a Japanese branded glow plug and an altitude limit of 5,200 m. The N3 costs £379.98 and the N2pro costs £499.98. Both have a 5 L tank and a timer. They also have a thermostat and a silent oil pump. The N2E, N2pro and N3 run on 12V and 230V only. All five models share the same 1,400-5,000 W power range. A reviewer noted that the wider model has a 5 L tank but no timer.
The page shows a £30 voucher on the N4 valid until 31 October 2026 or while stocks last. It is sold by LF Bros Official Store and fulfilled by Amazon. The page says the heater has an energy efficiency label range of A++ to G. Parts often bought with it are a 200 cm stainless steel exhaust pipe at £12.99 and a 10 m titanium fibre exhaust wrap at £12.99.
LF Bros says it has been making heaters since 2003 and sells in more than 20 countries. It is based in the coldest part of China. It makes all-in-one and split diesel heaters. The name stands for Loyalty and Fortitude with Bros for Brotherhood. The N4 is made in China. It uses a multi-pulse oil pump and motor control with a glow plug.
| Brand | LF Bros |
| Model number | N4 |
| ASIN | B0C7BS72QG |
| Colour | White |
| Fuel type | Diesel |
| Heating method | Forced air |
| Form factor | Pedestal |
| Mounting type | Floor mount |
| Dimensions (D x W x H) | 39 x 15.7 x 34.5 cm |
| Item weight | Approx. 7.26kg |
| Gross weight | 12.4kg |
| Thermal power | 1,400-5,000 W |
| Heat output | 4,700-17,000 BTU |
| Fuel consumption | 0.18-0.53 L/h |
| Fuel tank capacity | 3.5 L |
| Power supply | 12 V / 24 V DC / 220-240 V AC |
| Amperage | 15 A |
| Operating temperature | -40°C to 40°C |
| Temperature setting range | 10°C to 35°C |
| Heating coverage | 25 square metres |
| Altitude limit | 1,500 m |
| Timer | 24-hour programmable |
| Controller | LCD controller (upgraded T3) |
| Remote control range | Up to 30 m |
| Number of speeds | 1 |
| Fuel cap | Internally threaded |
| Special features | Energy efficient / fast heating / on-off timer / overheat protection / remote control |
| Recommended uses | Garage / greenhouse / home / patio / tent / warehouse / workshop |
| Country of origin | China |
| Warranty | 1 year |
