A correctly installed diesel heater can make your campervan or motorhome comfortable throughout the year.

WeConvert installs diesel air heaters in campervans, motorhomes and suitable self-build conversions from our private workshop in Blackburn.

Whether you need a heater fitting for the first time, want to replace an unreliable existing unit or need help diagnosing a heater that will not start, we can assess the vehicle and recommend a suitable solution.

We serve customers across Blackburn, Darwen, Accrington, Burnley, Rossendale, Bolton, Chorley, Preston and the wider Lancashire and North West area.

Campervan Diesel Heater Installation

Diesel air heaters use fuel from the vehicle or a separate fuel tank to provide warm air inside the living area.

They are popular in campervans because they:

• Use relatively little electrical power once running
• Provide controllable dry heat
• Can operate while the vehicle is parked
• Reduce reliance on campsite hook-up
• Make winter and shoulder-season travel more practical
• Help manage condensation when used with suitable ventilation
• Can be integrated into small or large conversions

A heater installation must be properly planned around the vehicle layout, available space, fuel supply, electrical system, hot-air routing and safe positioning of the combustion intake and exhaust.

We assess these factors before agreeing the installation.

New Diesel Heater Installations

We can install suitable diesel heaters in:

• Panel-van campervans
• Factory-built campervans
• Coachbuilt motorhomes
• Day vans
• Self-build conversions
• Partially converted vans
• Commercial vehicles with suitable enclosed accommodation or work areas

A typical installation may include:

• Diesel heater unit
• Heater mounting arrangement
• Hot-air ducting
• Warm-air outlet
• Controller
• Electrical supply
• Appropriate fusing
• Fuel line
• Fuel pump
• Fuel pickup or separate fuel tank
• Combustion air intake
• Exhaust system
• Heat protection where required
• Testing and commissioning

The exact installation depends on the heater model, vehicle construction and intended use.

Diesel-Heater Brands and Options

We install diesel air heaters from established manufacturers including Webasto, Eberspächer and AUTOTERM/Planar, together with selected customer-supplied heaters where the equipment is complete, suitable and supported by clear installation instructions.

Common options include:

• Compact 2kW diesel air heaters
• Higher-output 4kW and 5kW heaters
• Single-outlet and ducted installations
• Internal and suitable external mounting arrangements
• Standard and programmable controllers
• Replacement of existing diesel air heaters
• Diagnosis and repair of suitable existing systems

The correct heater depends on the vehicle size, insulation, interior layout, available mounting position and intended use. We assess the vehicle before recommending a heater or confirming the final installation price.

Webasto currently offers compact 2kW air heaters and larger 4–5.5kW models, while AUTOTERM similarly offers 2kW and 4kW air-heater ranges. That supports mentioning output options, but avoid claiming that a particular van always needs a particular size—the full installation matters.

Diesel-Heater Installation for Popular Vans

We can assess diesel-heater installations in vehicles including:

• VW Transporter T5, T5.1, T6 and T6.1
• Ford Transit Custom
• Vauxhall Vivaro, Renault Trafic and Nissan Primastar
• Citroën Relay, Peugeot Boxer and Fiat Ducato
• Ford Transit
• Mercedes Sprinter and VW Crafter
• Factory-built campervans and suitable motorhomes
• Professionally converted and suitable self-built vans

The mounting position, fuel connection, electrical supply and warm-air routing differ between vehicles, so every installation is checked before a fixed quotation is provided

Choosing the Right Heater Size

A larger heater is not automatically better.

An oversized heater may spend too much time running at its lowest setting, which can lead to inefficient operation and increased carbon buildup in some systems.

An undersized heater may struggle to warm a larger or poorly insulated vehicle.

The appropriate heater output depends on:

• Vehicle size
• Roof height
• Insulation quality
• Number and size of windows
• Expected outside temperatures
• Intended travel season
• Internal layout
• Number of warm-air outlets
• Whether heat needs to reach separate areas
• How quickly you expect the vehicle to warm up

Smaller vans commonly use compact heaters, while larger panel vans and motorhomes may require greater output or a more carefully designed ducting system.

We will recommend a heater based on the vehicle rather than simply fitting the highest-output unit available.

• Read our complete 2kW vs 4kW diesel heater comparison here.

Heater Location

A diesel heater may be installed internally or externally, depending on the vehicle and the heater manufacturer’s requirements.

Possible locations can include:

• Beneath a front seat
• Inside a suitable seat box
• Within a garage or storage area
• Beneath a raised bed
• Inside purpose-built furniture
• Under the vehicle using a suitable mounting enclosure
• Within an existing heater compartment

The selected location must allow for:

• Safe heater mounting
• Appropriate exhaust routing
• Combustion air intake
• Fuel-line routing
• Electrical access
• Hot-air ducting
• Service access
• Ventilation requirements
• Protection from water, road debris and stored items
• Sufficient clearance from heat-sensitive materials

We will not install a heater in a location that does not provide suitable access or safe routing for the associated components.

Fuel Supply Options

A diesel heater may take fuel from the vehicle’s main diesel tank or from a dedicated auxiliary tank.

Vehicle fuel tank connection

Where suitable, the heater can be supplied from the vehicle’s main tank using an appropriate fuel pickup arrangement.

This avoids the need to refill a separate heater tank.

The installation method depends on the vehicle, fuel tank design and access available.

Separate fuel tank

A dedicated heater tank may be appropriate where:

• The vehicle is not diesel powered
• Access to the main fuel tank is impractical
• The owner prefers a separate supply
• The heater uses a different fuel
• The vehicle layout makes a separate tank more suitable

Any auxiliary tank must be securely mounted and positioned so that it can be filled and inspected safely.

Fuel containers should not be loosely placed inside living or storage areas.

Hot-Air Ducting and Outlets

The warm-air outlet should be positioned where heat can circulate through the living area without creating an obstruction or directing excessive heat onto sensitive materials.

We consider:

• Heater outlet location
• Length of ducting
• Number of bends
• Duct diameter
• Airflow restrictions
• Furniture layout
• Bed and seating positions
• Access doors
• Stored equipment
• Heat-sensitive surfaces
• Whether more than one outlet is practical

Long, heavily restricted or poorly routed ducting can reduce heater performance.

In smaller campervans, a single well-positioned outlet may be more effective than several restricted branches.

Larger vehicles may benefit from multiple outlets where the heater and ducting arrangement are suitable.

Electrical Requirements

A diesel heater needs a stable 12V electrical supply for starting, operation and shutdown.

The heater may fail to start or display error codes if:

• The leisure battery voltage is too low
• The supply cable is undersized
• The cable run is too long
• Electrical connections are loose
• A poor earth connection is present
• The fuse or fuse holder is unsuitable
• The battery is worn or undercharged
• The electrical system cannot support the heater during startup

We assess the available electrical supply before installation.

Where required, the work may include:

• A dedicated fused supply
• Correctly sized cabling
• Suitable isolation
• Controller wiring
• Battery-system assessment
• Improvement of existing connections
• Integration with the campervan electrical system

A heater should not be connected to an unsuitable circuit simply because a convenient power supply is nearby.

Exhaust and Combustion Air

The combustion side of a diesel heater is separate from the warm air delivered into the vehicle.

The heater requires:

• A combustion air intake
• An exhaust outlet
• Secure mounting
• Appropriate heat protection
• Suitable clearance
• Correct routing beneath or outside the vehicle

The exhaust must be positioned to reduce the risk of fumes entering the living space through doors, windows, vents or floor openings.

It must also be protected from contact with combustible materials, wiring, fuel lines and vulnerable vehicle components.

The combustion intake and exhaust are installed in accordance with the heater manufacturer’s instructions and the practical limitations of the vehicle.

We will not route an exhaust into an enclosed compartment or beneath an unsuitable opening.

Diesel Heater Replacement

An existing heater may be worth replacing where:

• It is unreliable
• Replacement parts are unavailable
• The heater is incorrectly sized
• The installation is unsafe or unsuitable
• The controller has failed
• The unit is heavily carbonised
• The heater repeatedly locks out
• The existing system is poorly positioned
• A previous low-cost unit has reached the end of its useful life
• The vehicle owner wants a supported branded heater

A replacement does not always mean that every part of the original installation can be reused.

We assess:

• Mounting position
• Fuel line
• Fuel pump
• Exhaust
• Combustion intake
• Hot-air ducting
• Electrical supply
• Controller wiring
• Existing apertures
• Condition of surrounding materials

Where suitable, some components may be retained. Where the original installation does not meet the new heater’s requirements, additional work may be necessary.

Diesel Heater Fault Finding

A heater that will not start does not always need replacing.

Common causes can include:

• Low battery voltage
• Poor cable connections
• Blown fuse
• Air in the fuel line
• Empty or restricted fuel supply
• Incorrectly positioned fuel pump
• Blocked intake or exhaust
• Damaged ducting
• Controller fault
• Overheat shutdown
• Repeated failed-start lockout
• Carbon buildup
• Installation errors
• Faulty sensors or internal components

We can inspect the installation and determine whether the problem is likely to relate to:

• Electrical supply
• Fuel delivery
• Controller
• Ducting
• Intake or exhaust routing
• Installation quality
• The heater unit itself

Fault finding normally begins with a chargeable diagnostic assessment.

Where a repair is practical, we will explain the work required. Where the heater needs manufacturer-specific internal servicing, specialist parts or replacement, we will advise accordingly.

Common Heater Problems

The heater will not start

This may be caused by low voltage, lack of fuel, air in the fuel line, a blown fuse, controller problems or an internal heater fault.

The heater starts and then stops

Possible causes include poor fuel delivery, voltage drop, restricted airflow, overheating or an error condition.

The heater produces smoke

Some smoke during initial startup can occur, but persistent or excessive smoke may indicate poor combustion, fuel-delivery issues, carbon buildup or an installation problem.

The fuel pump is very noisy

The pump normally produces an audible ticking sound.

Excessive noise can sometimes be reduced through improved positioning, suitable mounting or isolation from furniture panels.

The heater does not warm the van

The heater may be undersized, the ducting may be restricted, warm air may be poorly positioned or the vehicle may have insufficient insulation.

The heater drains the battery

Diesel heaters need increased power during startup and shutdown.

Frequent failed starts, poor battery condition or insufficient charging can lead to battery problems.

Repositioning Existing Diesel Heaters

An existing heater may work but be poorly located.

We can consider repositioning a heater where:

• The warm-air outlet is ineffective
• The heater blocks useful storage
• Service access is inadequate
• Fuel-pump noise is excessive
• Exhaust routing is unsuitable
• The heater is exposed to damage
• Furniture modifications require the heater to be moved
• The installation needs improving as part of a wider conversion

Repositioning may require changes to:

• Floor apertures
• Mounting plate
• Exhaust
• Intake
• Fuel line
• Pump location
• Electrical wiring
• Hot-air ducting
• Furniture
• Heat protection

The existing apertures may also need to be safely sealed where they are no longer required.

Diesel Heaters for Self-Build Campervans

We can install diesel heaters as a standalone stage within a self-build campervan project.

This can be useful where the owner is completing the furniture and finishing work but wants the heater fitted professionally before the interior is closed in.

Ideally, the heater should be planned before permanent furniture is installed.

Early planning allows space to be reserved for:

• The heater
• Mounting plate
• Ducting
• Controller
• Fuel pump
• Electrical connections
• Service access
• Exhaust and intake routes
• Safe clearance from stored items

We can work with an incomplete van, provided the floor, insulation and surrounding structure allow a suitable installation.

Diesel Heaters in Motorhomes

We can install or replace selected diesel heaters in motorhomes where the vehicle construction and available space allow.

Suitable work may include:

• Adding a standalone diesel air heater
• Replacing an existing diesel heater
• Improving hot-air distribution
• Repositioning outlets
• Correcting installation issues
• Diagnosing electrical or fuel-delivery faults

Some factory-built motorhomes use integrated heating and hot-water systems.

These may require manufacturer-approved servicing or specialist diagnostic equipment.

We will explain where the work is better handled by an approved service centre.

Heater Controllers

Depending on the heater, controller options may include:

• Basic rotary controls
• Digital display controllers
• Timed operation
• Thermostatic control
• Remote controls
• Bluetooth or app-based control
• Altitude settings
• Diagnostic error displays

Controller features vary considerably between manufacturers and models.

We can explain the available operating modes and how to start, stop and adjust the heater correctly.

The heater should always be allowed to complete its shutdown cycle rather than having its electrical supply disconnected while running.

Carbon Monoxide Alarms

A suitable carbon monoxide alarm is an important safety device in a campervan or motorhome containing fuel-burning equipment.

A diesel heater’s combustion system should remain sealed from the living area, but an alarm provides additional warning if combustion gases enter the vehicle.

We recommend that customers maintain suitable:

• Carbon monoxide detection
• Smoke detection
• Ventilation
• Fire-safety equipment

Alarms must be installed, tested and replaced in accordance with the manufacturer’s instructions.

An alarm is not a substitute for correct heater installation and regular inspection.

Installation of Customer-Supplied Heaters

We may be able to install a heater supplied by the customer, subject to inspection.

Before accepting customer-supplied equipment, we consider:

• Manufacturer
• Model
• Product condition
• Installation instructions
• Completeness of the kit
• Availability of replacement parts
• Suitability for the vehicle
• Quality of supplied components
• Warranty arrangements

We may decline to install:

• Used heaters of unknown condition
• Incomplete kits
• Equipment without clear instructions
• Damaged components
• Products that appear unsuitable
• Equipment that cannot be supported or safely installed

The customer remains responsible for the warranty on customer-supplied equipment.

Our workmanship warranty does not cover failure of a product we did not supply.

Branded and Budget Diesel Heaters

There are significant differences in price, support, parts availability and warranty between heater brands.

A lower-cost heater may suit some budgets, but customers should consider:

• Product warranty
• Availability of replacement parts
• Technical support
• Controller quality
• Noise levels
• Fuel-pump quality
• Installation instructions
• Long-term reliability
• Approved service support
• Insurance requirements

We can discuss suitable options based on the vehicle, intended use and budget.

The cheapest kit is not always the lowest-cost option over the life of the vehicle.

Our Installation Process

1. Initial enquiry

Tell us about the vehicle, current conversion and how you expect to use the heater.

Include photographs of the interior, underside and any proposed installation location where possible.

2. Vehicle assessment

We inspect the available mounting locations, fuel options, electrical supply and potential exhaust and ducting routes.

3. Heater specification

We recommend an appropriate heater output and installation arrangement.

Where different options are available, we explain the advantages and limitations of each.

4. Written quotation

We provide a quotation covering the agreed heater, installation components and labour.

Any assumptions or exclusions will be clearly explained.

5. Installation

The heater, fuel supply, wiring, intake, exhaust and hot-air ducting are installed in accordance with the agreed scope.

6. Testing and handover

We run and test the heater, check the controls and explain correct startup, operation and shutdown.

You will also be shown the main components and advised on routine checks.

Why Choose WeConvert?

Installation planned around the vehicle

We consider mounting, airflow, fuel, electrical supply and service access together rather than treating the heater as an isolated component.

Campervan and motorhome knowledge

We understand how heating needs to work alongside insulation, ventilation, electrics, furniture and storage.

New installations and replacements

We can install a new heater, replace an existing unit or assess a heater that is not operating correctly.

Clear equipment options

We explain the differences between heater types and specifications without automatically recommending the most expensive system.

Suitable work on self-builds

We can install heaters in professionally converted vehicles and suitable self-build campervans.

Local workshop service

Our Darwen workshop serves customers from Blackburn, Accrington, Burnley, Rossendale, Bolton, Chorley, Preston and across Lancashire.

Vehicles We Work On

We can install diesel heaters in many campervans and motorhomes based on:

• Citroën Relay
• Peugeot Boxer
• Fiat Ducato
• Ford Transit
• Ford Transit Custom
• Volkswagen Transporter
• Volkswagen Crafter
• MAN TGE
• Mercedes-Benz Sprinter
• Renault Master
• Vauxhall Movano
• Factory-built campervans
• Coachbuilt motorhomes
• Suitable self-build conversions

The feasibility of an installation depends on the vehicle, available space, fuel arrangement and existing conversion.

What We Do Not Cover

Our diesel heater service does not normally include:

• Engine or mechanical repairs
• Vehicle fuel-system repairs unrelated to the heater
• LPG heater repairs
• General motorhome appliance servicing
• Manufacturer warranty work without prior agreement
• Installation in unsuitable or unsafe locations
• Repairs where approved parts are unavailable
• Work on severely damaged or contaminated heaters
• Use of unsuitable temporary fuel containers
• Installations that cannot meet the heater manufacturer’s requirements

Where specialist internal heater repair or manufacturer diagnostics are required, we may recommend an approved service provider.

Frequently Asked Questions

How much does a diesel heater installation cost?

The cost depends on the heater brand, heater output, mounting location, fuel supply, electrical work and the amount of ducting required.

We will normally need vehicle details and photographs before providing an estimate.

What size diesel heater do I need?

The correct size depends on the vehicle volume, insulation, window area and expected weather conditions.

A compact campervan may need a smaller heater than a long-wheelbase, high-roof van or coachbuilt motorhome.

Can you fit a diesel heater under a seat?

Possibly.

The seat base must provide sufficient space, safe routing and access for installation and maintenance.

Some vehicles and seat bases are more suitable than others.

Can the heater use fuel from the vehicle’s tank?

Often yes, subject to the vehicle design and a suitable fuel pickup arrangement.

Where this is not practical, a properly installed separate tank may be considered.

Can you install a heater I have already bought?

Potentially, provided it is suitable, complete and supplied with clear installation instructions.

We reserve the right to decline unsuitable or poor-quality equipment.

Do diesel heaters use much battery power?

They use more electrical power during startup and shutdown, then normally use less once running steadily.

The exact demand depends on the heater and operating level.

A healthy leisure battery and suitable charging system are important.

Why is my diesel heater smoking?

Possible causes include failed starts, air in the fuel line, poor combustion, restricted intake or exhaust, incorrect installation or carbon buildup.

Persistent smoke should be investigated.

Can you repair a diesel heater fitted by someone else?

Yes, subject to inspecting the installation and heater.

We may be able to correct external installation issues, but some internal repairs require manufacturer-specific parts or specialist support.

Does a diesel heater produce carbon monoxide?

Combustion produces exhaust gases, which should remain outside the living area through the sealed combustion system and correctly installed exhaust.

A carbon monoxide alarm should still be fitted and maintained as an additional precaution.

Can I use the heater while sleeping?

Many diesel heaters are designed for extended operation when correctly installed and maintained.

Customers must follow the heater manufacturer’s operating instructions and maintain working carbon monoxide and smoke alarms.

How long does installation take?

A straightforward installation may be completed within one workshop day.

More complex installations, replacements or work requiring furniture alterations can take longer.

Request a Diesel Heater Quote

To help us assess the installation, please provide:

• Vehicle make, model and year
• Campervan or motorhome type
• Wheelbase and roof height
• Whether the vehicle is diesel powered
• Existing leisure battery details
• Current interior layout
• Proposed heater location, if known
• Whether a heater is already installed
• Heater brand and model, if already purchased
• Photographs of the interior and underside
• Your postcode
• Preferred timeframe
• Approximate budget

Whether you need a first-time installation, a replacement heater or help diagnosing an existing system, we can assess the vehicle and recommend a practical heating solution.