Campervan Heating, Cooling & Ventilation: Complete Guide
Climate control is not a luxury in a campervan — it is the difference between comfortable sleep and a miserable night. In the UK, Germany, and the Netherlands, temperatures range from well below freezing in January to the mid-30s°C in a summer heatwave. A well-chosen combination of heating, ventilation, and cooling lets you travel comfortably year-round without relying on campsite hook-ups. This guide covers every option: diesel and gas heaters, roof air conditioners, ventilation fans, and the insulation foundation that makes all of them more effective.
Why Campervan Climate Control Differs from Home
A van is a metal box with a very high surface area to volume ratio. It heats up in the sun far faster than a house and loses heat overnight far faster than an insulated brick building. The mass of metal around you conducts heat freely until you interrupt that process with insulation and manage the air inside with heating or cooling.
The good news is that the small interior volume means relatively modest equipment can make a significant difference. A 2kW diesel heater will warm a Sprinter-sized van in 15 minutes, even in −10°C conditions. A 1,500W roof air conditioner will cool the same space to a comfortable temperature in under 20 minutes on a hot afternoon. Knowing which device to use, and when, is the core skill of year-round vanlife in northern Europe.
Diesel Heaters: The Off-Grid Standard
Diesel heaters are the default choice for serious vanlifers in the UK and northern Europe, and for good reason. They use a small amount of fuel from your van's own tank (or a separate diesel jerry can), consume modest 12V power — typically 10–25W at cruise output — and require no gas supply. They heat quickly, run quietly at low output, and can be programmed to turn on before you wake up.
Eberspächer Airtronic
Eberspächer is a German company and one of the two dominant names in diesel air heaters for vehicles. The Airtronic D2 (2kW) and D4 (4kW) are OEM fitments in many premium motorhomes and campervans. They are reliable, well-supported, and backed by a substantial dealer network across Europe. The D2 is appropriate for vans up to about 6 metres; the D4 suits larger motorhomes or particularly cold climates. Current Airtronic models include Bluetooth control via the EasyStart Pro controller.
Webasto Air Top
Webasto is the other market leader, also German, with an equally strong reputation in the marine and automotive sectors. The Air Top Evo 3500 and 5500 are popular van fitments, with stepless power control (not just on/off switching at fixed levels) making them very responsive and quiet at low settings. Webasto units are particularly common as factory options on high-spec campervans and motorhomes across Germany and the Netherlands.
Budget Diesel Heaters
A wave of Chinese-manufactured diesel heaters — sold under names such as Vevor, Autoterm, and various rebadged versions — has made diesel heating accessible at a fraction of Eberspächer and Webasto prices. These units (typically 2kW or 5kW) can perform reliably, but quality control varies between batches and after-sales support is limited. For occasional users or those comfortable with self-diagnosis and repair, they represent reasonable value. For full-time living in remote locations, investing in a European-branded unit is the lower-risk choice.
Browse our full range of heaters for campervans and motorhomes.
Installation Considerations
Diesel heaters draw air from inside the van, burn it with diesel, and expel combustion gases through a sealed exhaust pipe to the outside. Correct installation of both the fuel intake and exhaust is critical: the exhaust must exit away from any openings through which combustion gases could re-enter the vehicle. The fuel pickup should be from the lowest accessible point in the fuel line, or from a separate small tank if the main tank is not easily accessible.
Route the warm air outlet strategically — typically under the bed or towards the floor, so warm air rises and distributes evenly. A Y-duct with two outlets helps in longer vans.
Gas Heaters: Truma and Propex
Gas-fired space heaters are an alternative to diesel units, particularly for users who already carry LPG for cooking or water heating. The Truma Combi system is the market-leading choice for motorhomes and upmarket van conversions: a single unit provides both space heating and hot water, running on LPG. It is compact, quiet, and the standard equipment in many Hymer, Bürstner, and Knaus motorhomes sold in Germany and the Netherlands.
Propex HS2000 and HS2211 heaters are a popular standalone gas option in UK van conversions, drawing on LPG or propane and requiring no 230V power (12V control only). They are a good choice for those who primarily stay at UK campsites with gas supplies.
The practical disadvantage of gas heaters for off-grid travel is the need to carry and manage gas cylinders. Gas usage is also harder to monitor than diesel, which comes from a tank with a gauge. For cross-European travel, gas cylinder compatibility is a recurring inconvenience (UK Calor-fittings differ from European DIN regulators).
Roof Air Conditioners
Air conditioning in a campervan was once the preserve of large motorhomes permanently connected to hook-up. Increasingly, 12V and low-voltage roof air conditioners make it viable in self-built vans with substantial battery banks.
230V Rooftop Air Conditioners
Dometic's Freshwell, Truma Aventa, and the Fiamma Polar range are all 230V rooftop air conditioners designed for motorhomes and campervans. They require a continuous 230V supply — either from a campsite hook-up or from a powerful inverter. Power draw is typically 1,200–1,800W, so running from batteries alone requires at minimum 300Ah lithium and a 2,000W inverter, giving only 1–2 hours of runtime without recharging. For campsite users, these are an excellent option for European summer heat.
12V / Low-Voltage Air Conditioners
A newer category of direct-12V (or 24V) air conditioners has appeared in recent years, aimed specifically at campervans and trucks. Units from brands including Dometic, Vevor, and Alpicool draw 400–700W, making them far more compatible with off-grid battery systems. A 400W unit running from a 200Ah LiFePO4 bank can cool for 4–6 hours from a full charge — enough for overnight comfort in moderate heat.
These units are not as powerful as full 230V systems and will struggle in extreme heat (above 35°C ambient), but for UK and northern European summers where temperatures rarely exceed 30°C for extended periods, they are a practical off-grid cooling solution.
View our range of air conditioners for campervans and motorhomes.
Ventilation Fans: Maxxair and Fiamma
A powered roof vent fan is one of the most effective and energy-efficient ways to manage temperature inside a campervan. In mild weather, it often removes the need for either heating or air conditioning — fresh air circulation keeps the van comfortable across a wide range of conditions.
Maxxair MaxxFan
The MaxxFan is the benchmark ventilation fan in the van conversion world. Available in 30cm and 40cm sizes, it features variable speed control, an integrated lid that can remain open in light rain, and a reverse mode that draws air out of the van (pulling fresh air in through other openings). Power draw is modest — typically 3–8W depending on speed setting. The Deluxe model includes a remote control and thermostat.
Fiamma Turbo Vent and Heki
Fiamma's Turbo Vent series is a popular alternative in Europe, with a robust build quality and competitive pricing. The Dometic Heki rooflight combines a skylight with an integrated flyscreen and ventilation blind, and is particularly popular in German and Dutch motorhome conversions where daylighting is valued alongside ventilation.
Fan Placement Strategy
A single fan directly above the sleeping area is the standard setup for condensation control and overnight comfort. Two fans — one at each end of the van — allow a through-flow of air that is significantly more effective at cooling in warm weather: one fan draws fresh air in while the other exhausts hot air out. Always use insect screens over all open vents when parked in areas with mosquitoes — essential in southern Germany and the Netherlands in summer.
Insulation: The Foundation of Climate Control
No heating or cooling system performs well in a poorly insulated van. Insulation reduces heat loss in winter, prevents heat gain in summer, and — critically — controls condensation, which is caused by warm moist air meeting cold metal surfaces.
Materials
- Spray foam: Fills voids perfectly and adheres well to metal, but difficult to remove if you later need to access the body. Best used in cavities and around wheel arches.
- PIR board (Celotex, Kingspan): High R-value per millimetre, rigid, easy to cut. The preferred choice for flat walls and floor. 50mm PIR is equivalent to around 100mm of mineral wool in thermal resistance.
- Mineral wool (Rockwool): Excellent acoustic properties, cheap, and flexible enough to fill irregular cavities. Must be kept dry — if it absorbs moisture it loses much of its thermal value.
- Sheep's wool: Natural, hygroscopic (manages moisture rather than fighting it), and increasingly popular in eco-conscious builds. Less thermal resistance per millimetre than PIR, but more forgiving in humid conditions.
- Reflective foil: Effective at blocking radiant heat from the sun (useful on the roof in summer), but adds negligible thermal resistance in isolation. Often used in conjunction with PIR board.
Condensation Control
Condensation forms when warm, moist air (from breathing, cooking, and damp clothing) contacts a cold surface. It is the most common cause of mould and rot in campervan conversions. The solution is a continuous vapour barrier on the warm side of the insulation, combined with adequate ventilation to remove moist air from the living space. Running a roof fan on low for 15 minutes before sleeping clears the bulk of moisture generated during the day. A small dehumidifier, or desiccant sachets in enclosed spaces, helps during extended periods in damp UK weather.
When to Choose What: UK, Germany and Netherlands Climate Guide
| Scenario | Best Solution |
|---|---|
| UK autumn/winter, off-grid | Diesel heater (Eberspächer or Webasto) + roof fan for ventilation |
| UK summer, wild camping | Roof fan (Maxxair or Fiamma) + 12V low-voltage AC if very hot |
| Germany winter (Bavaria, Black Forest) | Diesel heater 4kW+ with good insulation, electric blanket for nights |
| Netherlands summer (coastal) | Roof fan often sufficient; coastal breeze offsets heat effectively |
| Campsite hook-up user, summer | 230V rooftop AC (Dometic Freshwell, Truma Aventa) |
| Full-time liveaboard, year-round | Diesel heater + 12V AC + Maxxair fan — cover all bases |
Frequently Asked Questions
What is the best heater for a campervan?
For off-grid use, a diesel air heater from Eberspächer or Webasto is the most practical choice for UK and northern European travel. They use fuel from your van's tank, consume minimal 12V power, and heat the space quickly. If you already have LPG aboard for cooking, a Truma Combi provides combined heating and hot water efficiently. Budget-friendly Chinese diesel heaters can work well but carry more reliability risk for long-distance or remote travel.
Can I run air conditioning in a campervan without hook-up?
Yes, with a sufficient battery bank and a low-voltage air conditioner. A direct 12V unit drawing 400–600W can run for 4–6 hours from a 200Ah LiFePO4 battery at full depth, or longer at moderate settings. Pair with adequate solar to recharge during the day. Standard 230V rooftop units require an inverter capable of sustained 1,500W+ output, which depletes even large battery banks in 2–3 hours.
How do I stop condensation in my campervan?
Good insulation that eliminates cold metal surfaces inside the van is the primary fix — spray foam in cavities and PIR board behind cladding panels removes the surfaces on which condensation forms. Ventilate regularly, particularly after cooking and sleeping, using a roof fan on extract mode. Keep a small desiccant dehumidifier in enclosed storage spaces. Avoid drying wet clothing inside a poorly ventilated van.
Is a diesel heater safe to use while sleeping?
Yes, when correctly installed. Diesel heaters are combustion-sealed systems — the burner takes in air from outside and exhausts combustion gases outside through a dedicated exhaust pipe, so no carbon monoxide enters the living space. However, always fit a CO detector as a precaution, and inspect the exhaust and fuel lines annually. Never use an open-flame gas stove or charcoal for heating inside a van.
How much insulation do I need in a campervan?
There is no single figure, as it depends on van model, climate, and build complexity. As a practical target for year-round UK and northern European travel: 50–75mm of PIR board or equivalent in walls and ceiling, 25–50mm in the floor, and spray foam in all cavities and around the outer body ribs. This level of insulation, combined with a decent diesel heater, will keep the van comfortably warm at −10°C overnight with modest fuel use.
