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Webasto Air Top EVO 40 motorhome 4.0kW heater kit 12v twin outlet
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Webasto Air Top EVO 40 motorhome 4.0kW heater kit 12v twin outlet

Part Number: AT3900MHKIT12V
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  • Free UK Delivery when you spend £90.00 + VAT
Now $1,446.80 (ex. VAT) (FREE UK Delivery)
Was: $3,318.70 (ex. VAT)  |  You Save: $1,871.90 (ex. VAT)
( $1,736.16 (inc. VAT) inc. VAT)
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The Webasto Air Top Evo40 heater offers optimized fuel efficiency, a compact, quiet, and economical heater requiring less than 1 litre of diesel fuel for 1 hour of maximum, whisper quiet heating. Programmable independent heating (does not use heat from the engine) for many types of RV, Motorhome & Caravan installations.

Please Note -  When above timer upgrade is chosen from this listing, the standard controller pictured will be removed from the kit (if applicable). 

Product highlights

• Compact heaters with proven efficency

• New and improved technology, e.g. with respect to service life and heat up time

• Easy installation, underfloor or in the interior

• Constant ambient temperature, continuous control

• Automatic altitude function for all Air Top Evo models

• Low power consumption, quiet operation

• Intelligent Blower Control


This Webasto Air Top Evo 40 heater kit comes with a complete installation kit to install into your vehicle. Supplied with a rotary rheostat temperature control we also offer the option of the MC AirTop EVO Control or digital timer. This kit includes ducting & air outlets for additional ducting accessories, please see our range of additional ducting outlets and digital controllers to enable a truly bespoke and cost-effective heating solution.


Webasto Twin Outlet Kit contents

Everything you need to complete a professional installation

•   Webasto Air Top Evo 40 12 volt diesel heater with rotary rheostat temperature control

•   (Upgrade to 7 day Timer Programmer or MC AirTop EVO Control – please enquire if required)

•   All electrical harnesses and connections

•   Steel heater mounting plate, to protect wood or composite floors

•   Exhaust silencer included for quiet operation

•   1 x 1m & 1 x 0.5m of stainless steel exhaust pipe with clamps &

•   (Please see our section for additional lengths exhaust pipe if required) 

•   Combution Intake silencer 

•   Includes 1m x 60mm flexible ducting and 1.5m x 90mm flexible ducting

•   (Additional ducting required? Please see our ‘other items’ )

•   1 x Air entry grille

•   1 x 90mm Open vent & back nut

•   1 x 60mm closable vent & back nut

•   1 x 90x60x90mm ‘Y’ branch

•   ( Please see our ducting accessories for additional air outlets, Y Branches & vents)

•   Fuel system with 8m plastic fuel pipe, complete with fuel metering pump & anti vibration mountings

•   Kit supplied with 8mm fuel t-piece.(does NOT include fuel standpipe – please enquire if required)

•   All necessary clips and screws for standard installation included

•   Comprehensive installation manual

•   Webasto 24 months warranty.


 This is a genuine Webasto UK Warranted RV, Motorhome & Caravan heater kit

 36 months Genuine Webasto UK Warranty

 Applications also Include:

•   Vans and Small Buses

•   RV's, Caravans & Mobile Homes

•   Camper vans

•   Horse boxes

•   4 x 4 Vehicles

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Please Note: Delivery prices quoted are excluding VAT.

UK Postage Table

 * UK Mainland only

Deliveries are made from Monday to Friday excluding Bank and National  Holidays.

Next Working Day Shipping * is available in UK Mainland for all orders placed before 15:00hrs. Orders placed after 15:00hrs will be dispatched the following working day on a next day service. For Next Business Day Delivery, please use the drop down menu under Shipping Options and select Next Day.

Standard 2-day shipping * is available to Scottish Highlands and Islands orders placed before 15:00hrs on stocked items. Items are despatched promptly sameday. UK Courier services are typically 2 day delivery for remote UK postcodes

WEEKEND deliveries in the UK may be possible if required at additional cost. For WEEKEND delivery quotation please call our Sales Team prior * 

Standard carriage / Free-shipping - please allow 2-5 working days from clearance of payment for delivery. Typically however delivery is much quicker and 98% of orders are delivered to UK addresses within 24 - 48 hours after dispatch from warehouse.

Delivery Times - Deliveries are made Monday to Friday (excl. public holidays) typically 2-5 working days from date of order for in-stock items if the FREE DELIVERY option is chosen. An email will be sent to inform you of dispatch of goods and due delivery date.  Next Day UK delivery may be selected at checkout for an additional cost.

CANCELLATIONS and RETURNS - from our Online shop

(not including manufacturer warrantable items. Please speak to our Sales department or email if you believe your item has failed within warrantable circumstances)

You have the right to cancel your order within a 14 (fourteen) day "cooling off period", which starts the day after you receive your items.

If you wish to cancel under the UK Consumer Protections (Distance selling) Regulations 2000, you must inform ButlerBus Technik Ltd of your intention to cancel your order by either phone, email or post within the 14 (fourteen) day cooling off period.

You will then receive confirmation from ButlerBus Technik Ltd and given authorisation to return goods, please quote and include your original invoice number. We will only except goods back in a re-saleable condition.

Once we have received goods we will then issue you a full refund less any delivery charges. (You will be required to return goods at your cost by an insured and trackable method) If goods go missing we will only consider a

request for refund on proof of completed receipt/delivery of goods to ButlerTechnik from your nominated courier.

If you are unable to arrange a return please contact us. We can arrange collection on your behalf but a charge will be made which will be deducted from your refund total.

If a delivery charge was made on the original purchase this will not be refunded as this is a service which is concluded at the point of order. 

Orders that have already been processed and/or despatched cannot be cancelled; they must be returned to ButlerBus Technik Ltd for refund following receipt of goods by customer.

We will do our very best to assist and enable a quick refund process upon receipt of returned items.

Thank you for your continued understanding during this process

Returns address
ButlerBus Technik Ltd
Tillbridge Road Garage
United Kingdom

All costs relating to return shipping of correctly supplied goods shall be the responsibility of the purchaser.

ButlerBus Technik Ltd are not responsible for any shipping or insurance charges relating to return of goods. 

Please be aware that ButlerBus Technik Ltd may NOT be able to accept for full or partial refund/credit any items that have been prior installed by the customer before return.

Such goods/components shall be deemed 'used' and therefore unable for subsequent resale.

Specifically, but not exclusively, the return of prior installed electronic items used for purchaser diagnostic or trouble-shooting purposes shall not be considered for full refund. 

The decision to refund or partially refund prior installed items shall remain solely at the discretion of ButlerBus Technik Ltd.

The decision to refund or partially refund goods returned beyond 14 days after original date of sale shall remain solely at the discretion of ButlerBus Technik Ltd.

Your statutory rights are unaffected by the above. Consumers other than Business trade customers are further protected by

UK Consumer Protection (Distance Selling) Regulations 2000