At a Glance
- A diesel heater for a van, boat or cabin gives dry, ducted warmth from the same fuel your engine or generator already uses.
- LPG heaters are cheaper to buy and simpler to fit, but bottled gas is one more fuel to find, carry and store.
- Flueless gas heaters put water into the air. Diesel heaters and flued gas heaters send their exhaust outside.
- The right answer depends on what else on board burns fuel, how much power you have, and where you’ll spend the winter.
If you’re planning to live in a van, on a boat or in a small cabin, space heating is the decision that shapes your winter. A diesel heater for van life or boat life has quietly become the default for a lot of people, and yet LPG still has plenty going for it.
This article is about keeping the space warm, not the water. Hot water is covered in How Do I Get Hot Water Off-Grid?, so here the question is simpler: which fuel should heat the air you sit in?
There isn’t one right answer. There is a way to decide, and it starts with what you already carry.
How a Diesel Heater Works
A diesel heater is a small sealed furnace.
A pump draws diesel from a tank, a glow plug lights it in a combustion chamber, and a fan blows cabin air over the hot metal and out through ducting. The exhaust leaves through its own pipe outside.
Think of it like a hair dryer sitting on a tiny bonfire that’s been shut inside a metal box. The air you feel never touches the flame, which is why the warmth is dry and why the exhaust must go outside.
Most units run on 12V or 24V, so they suit vans, boats and cabins with a battery bank. They draw a burst of power on start-up while the glow plug heats, then settle to a few watts for the fan.
Fuel use for a 2kW diesel heater is roughly a tenth of a litre an hour on low, up to a quarter of a litre flat out, and it depends on the model and how cold it is.
Dry heat, low running draw, one fuel. That’s the appeal.
How LPG Heating Compares
LPG heaters come in two families, and they’re very different animals.
A flued gas heater, the kind fitted to caravans and many narrowboats, burns bottled gas and vents its exhaust outside. It’s quiet, needs almost no electricity, and gives the same dry warmth as diesel.
A flueless gas heater, whether a portable cabinet heater or a catalytic panel, vents into the room.
It’s cheap and instant, but burning gas produces water, so it steadily dampens the space you’re trying to keep warm. In a van or boat that already fights condensation, that matters more than the price tag.
Gas is simple to fit and cheap to buy. The cost is in the bottles you’ll be carrying for years.
One Fuel or Two
This is the question that settles it for most people.
If you cook on gas and run a gas fridge, adding a gas heater means one fuel for everything, and that’s a perfectly good set-up.
If you’ve moved to induction cooking and a compressor fridge, as many people now have, bottled gas would exist only to heat the space. At that point a diesel heater removes a fuel type from your life entirely.
Diesel is easier to find than gas in remote spots too. Every filling station sells it, and a boat or van with a diesel engine can draw the heater from the main tank.
Gas bottles vary by supplier and can be a nuisance to exchange far from a town.
Count the fuels you’d carry with each option. Fewer is nearly always better.
Power, Noise and Ducting
A diesel heater needs electricity. The start-up draw is short but real, so on a boat or in a cabin with a small battery bank, a cold week of frequent starts adds up.
If your solar is modest, look at how off-grid solar systems work before choosing, and remember that a vehicle can top the batteries up from the alternator.
Diesel units also make noise. The fuel pump ticks and the exhaust has a low roar outside, which neighbours on a mooring notice more than you will. A flued gas heater is close to silent and barely touches your batteries.
Ducting favours diesel. One heater can feed warm air to two or three outlets, so a long narrowboat or a cabin with a separate bedroom heats evenly. A gas heater warms the room it sits in.
If your electrical system is small, gas is kinder to it. If your home is long, diesel spreads the heat.
Safety and Certification
Both fuels are safe when the installation is right, and both can hurt you when it isn’t.
Every diesel or gas heater needs its exhaust outside and a carbon monoxide alarm inside. On boats in England and Wales, the Boat Safety Scheme has required a working CO alarm since April 2019 and its examiners check heater exhausts and fuel lines every four years.
The Scheme specifically warns against fitting a diesel heater with a road vehicle exhaust, because those aren’t gas tight and can leak fumes into the cabin.
Gas installations on boats are also inspected under the Scheme. In a van there’s no equivalent test, so the standard you fit to is the one you set yourself, and your insurer may ask questions.
If you’re outside the UK, check the rules for your own waterways or vehicle type, because they vary a lot.
Certification is the minimum. A CO alarm you test is the part that actually keeps you alive.
Van, Boat or Cabin
It depends on what you’re heating and how you already live. A few honest patterns:
- A campervan with induction cooking and a decent battery bank usually suits a small diesel heater, drawing from the vehicle tank.
- A narrowboat with gas cooking and a modest electrical system often runs best on a flued gas heater or a solid fuel stove, with diesel as the upgrade when the batteries can carry it.
- A cabin with a generator or diesel store suits a diesel heater, because the fuel is already on site and the ducting reaches every room.
- A summer-only or occasional space can get away with gas, because fuel handling is rarely the problem for a few weekends a year.
The best heater is the one that fits the fuels, power and space you already have, not the one your neighbour swears by.
Final Thoughts
Diesel heaters have earned their popularity. They’re dry, they duct, and for anyone who has already left gas behind they remove a whole fuel type from the winter. LPG still wins on price, silence and simplicity, especially where gas is already doing the cooking.
Write down every fuel you’d carry, add up your battery capacity, and picture the coldest week of the year. The answer usually appears before you’ve finished the list.
If you’d rather have a specialist fit either system, off-grid heating installers are listed in our Business Catalogue.
To find out more about off-grid living return to our Reading Room.