The best diesel heaters for boats have seen some great improvements over the past few years. They’re the most common form of heating onboard sail boats and motorboats. Duncan Kent talks through the options and what to avoid. Best diesel heaters for boats \u2013 This article was first published 7 July 2021 \u2013 it was revised and updated 14 Jan 2025<\/p>\n
I live on my boat all year round, come rain, hale, snow and heat wave. The climate I live in lends itself to having some reliable heating fitted. It can be very tempting to try one of the very low priced copies of the real deal heaters from Webasto or Eberspacher.
\nA good number of the low-cost, often cloned diesel forced air heaters available online do not conform to UK or EU laws and regulations.
\nMost budget diesel forced air heaters were originally designed for trucks or motorhomes, which have different requirements and are not subjected to such a vigorous environment as that found in a sea-going yacht.
\nI bought a second hand Taylors Paraffin heater for one of my boats, after paying for it to be professionally serviced and important bits replaced, it was still slightly less expensive than new, but not by much.
\nI chose the Taylors heater because it requires no electricity at all.\u00a0 But it\u2019s a faff compared to pressing an igniter button and having hot air pumped around the place which is what you get with a blown air heater. The downside is that they need some electricity to keep working and they\u2019re noisy, especially for the neighbours who have to put up with the exhaust noise.
\nThere\u2019s a few second hand heaters on the market. Make sure if you do buy something second hand, that you get it professioanlly serviced and also when running any kind of combustible burner inside your boat ensure you have a good quality carbon monoxide detector fitted to your boat.
\nBuyer beware. We recommend trusted heater manufacturers with certified warranties and customer service backup. Buying a diesel heater intended for use in road vehicles rather than boats, or a diesel heater that does not meet UK safety standards, could pose a risk to life.
\nIf you want heating you can trust then here\u2019s our guide to the best diesel heaters for boats
\nWe\u2019ve divided this guide into two sections, with the best boat heaters for boats up to 38 foot and the best diesel heaters for boats over 40 foot.
\nThe best Diesel heaters for boats up to 38 foot
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Eberspacher Espar Airtronic S2 D2 L 12V 2.2kW (7500BTU) with EasyStart PRO 7 Day Timer
\nOne of the most popular manufactures of best diesel heaters for boats , Eberspacher, has recently upgraded its Airtronic heaters, giving them a power boost mode for fast initial heating plus continuously variable temperature settings.
\nThey also now have a fresh air mode to improve air circulation through the boat on warm days.
\nYears of continual development has made these heaters more economical, quieter and more importantly, reliable.
\nThe wide range of controls on offer includes various panels with switches and LCDs, or there\u2019s the latest, EasyStart Call, which allows you to operate your heater using the proprietary smartphone app.
\nThe app turns your phone screen into a simulated control panel and transmits your selected settings to a GSM module installed in the heater.
\nModels include the Airtronic D2 and S2 D2L (<32ft LOA), D4+ and M2 D4L (26-39ft), D5 (36-49ft) and the D8LC (49-62ft).
\nBuy it now from Amazon<\/p>\n
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Note: We may earn a commission when you buy through links on our site, at no extra cost to you. This doesn\u2019t affect our editorial independence.<\/p>\n
Webasto Air Top 2000 STC 12v Marine diesel boat heater kit
\nWebasto\u2019s steplessly modulated heating systems are renowned for their high build quality, performance and reliability.
\nThe range features numerous safety devices and procedures, including flame detection and exhaust heat sensing, to ensure safe operation.
\nThe smaller and less sophisticated model is its Airtop 2000STC, a 2kW heater that offers up to two outlets, thermostatic controls, external temperature sensor, air intake silencer and low-noise fuel pump.
\nThe new MultiControl digital timer\/temp controller offers instant access to functions plus a quick start button and is sealed against water ingress.
\nWebasto are known as one of the leading manufacturers of best diesel heaters for boats and appear much the same as Eberspacher heaters\u2026 but they are different and have small differences.
\nFor larger yachts there\u2019s the high-output, multi-mode Airtop Evo 3900 (<40ft) or 50 (<50ft).
\nBoth are powerful, yet quiet and economical and can be controlled using a MultiControl, a TeleStart wireless remote pad or via a mobile phone app using its ThermoCall system.
\nThe temperature is regulated using intelligent blower control whereby the heater output and fan controls are separately sensed to reduce power and fuel consumption.
\nThe Evo series has also been upgraded with ECO mode for reduced electrical power consumption, Boost mode for maximum output and Ventilation mode to provide fresh air to the cabins on a hot day.
\nBuy it now at Amazon<\/p>\n
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Wallas 22GB Coastal Kit
\nWallas recently updated its 2.2kW (22GB) and 3.2kW (30GB) Nautic models by changing their blower motors to brushless types.
\nThe result is more power and output capacity, allowing the boat to heat up quickly, efficiently and quietly.
\nIts new laminar flow burner offers low emissions of CO2 and NOx, and is designed to work with blended bio-diesel.
\nRenewable materials are used in its construction, although it retains high-grade aluminium components where necessary.
\nThe new control panel offers smooth PI-controlled thermostat adjustment and two-step air boost protection against accidental operation.
\nBuy from Kuranda<\/p>\n
Like most systems now, Planar heaters can be controlled via your phone
\nNew kid on the block, Russian-built Planar heaters appear to be a genuine compromise between cost and quality, although there seems to be little difference in the latter to the higher-priced brands.
\nPlanar\u2019s UK distributor is currently small, yet it holds a full range of spare parts (unlike many of the cheaper Chinese models) and the reviews on its service have so far been excellent.
\nIts Autoterm Air marine range comprises a 2kW and 4kW heater; however, larger units can be made specifically to suit.
\nThe standard kit comes with a basic rotary control panel offering stop\/start, capacity and air temp control and LED indication of heater status.
\nThe next level has an additional seven-day timer, ventilation mode and an LCD for temperature indication.
\nFinally, there\u2019s a GSM modem option with smartphone app for remote operation via the mobile phone network.
\nThis offers all the features of the more advanced LCD control panel, only on your smartphone.
\nVisit www.planarheaters.co.uk<\/p>\n
Refleks Stove Heater Refleks 11032-66M heater
\nThe Refleks stoves are popular with more traditional year round cruisers. Seen in working boats, fishing boats and a wide array of sail boats and traditional motor cruisers, the Refleks diesel heaters are king of the cold. They\u2019re sturdy drip fed units that radiate heat rather than blow it around.
\nThe larger Refleks stove heater models have additional internal pipework that allows further radiator heat or hot water heating. This small unit is the most basic and most budget friendly though and considered practically bomb proof.
\nThe advantage of the drip fed heaters is that you don\u2019t get the loud exhaust noise associated with blown air diesel heaters.
\nTotal heat output: 1.6 kW (1400 kcal\/h)
\nFuel consumption: min. 0.12 l\/h
\nFuel consumption: max. 0.30 l\/h
\nThis one is for area volume sizes of approx. 14 \u2013 23 Cu. Mtrs.
\nBuy now from Hartlepool Marine Supplies
\nfor more info on Refleks heaters go to the manufacturer site<\/p>\n
Blakes Lavac Taylors Diesel Heater Britannia 079D Stainless Steel
\nFuelled by red or clear diesel, fed from from its own gravity tank \u2013 Header tank version \u2013 or pumped direct from the boat\u2019s supply \u2013 main fuel tank version.
\nIt is a superbly simple heater for boats. Fitted to a bulkhead the heater radiates heat rather than pumps hot air around ducting.
\nAs a gravity fed unit this is virtually silent running.
\nAn excellent choice for anyone wanting to live aboard or use their boat year round. This model suits a smaller boat up to 38 foot.
\nFeatures:
\nMade of high-quality materials well bolted together
\nUp to 2.1 kilowatt output
\nFront opening door gives access for maintenance or adjustment
\nSupplied with a 1.5 gallon tank, a safety on\/off fuel control valve, in-line fuel filter, pipe work and fittings for installation
\nExternally vented and bulkhead mounted
\nThrough-deck fitting flue sections also supplied
\nAvailable in a brass or a Stainless Steel finish.
\nBuy it from Marine Store<\/p>\n
The best Diesel heaters for boats over 40 foot
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\nA digital timer offers instant access to functions
\nWebasto Air Top Evo 3900 Marine Heater
\nWebasto\u2019s steplessly modulated heating systems are renowned for their high build quality, performance and reliability.
\nThe range features numerous safety devices and procedures, including flame detection and exhaust heat sensing, to ensure safe operation.
\nThe new MultiControl digital timer\/temp controller offers instant access to functions plus a quick start button and is sealed against water ingress.
\nECO mode for reduced electric consumption, power mode PLUS for +10% more heat output (from 3,500 W to 3,900 W) and ventilation mode to supply fresh, cold air to the interior on hot days.
\nIt is supplied with a universal marine kit which includes copper fuel piping and appropriate connections, fittings for installation and rotary controller. Ducting or Outlets are sold separately as an added extra.
\nFuel Consumption Control Range: 0,17 \u2013 0,42 l\/h -Nominal power consumption control range: 15-36W \u2013
\nWeight: 5.9kg -L x W x H: 425 x 148 x 148 mm
\nBuy from Gael Force Marine<\/p>\n
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Webasto Air Top EVO 40 4kW 12v Marine Heater Kit with MultiControl HD 7-Day Timer
\nThe Webasto Air Top EVO 40 is compact, quiet, and economical heater requiring from 0.18 to 0.43 litres of diesel per hour.
\nSuitable and trusted for many types of marine installations and certified for installation in passenger areas and in proximity to dangerous substances.
\nThis Webasto Air Top EVO 40 heater comes with a complete installation kit to install into your boat. This components option can also be viewed perhaps as a starter kit, supplied with basic electronic temperature control. This kit does not include ducting or air outlets \u2013 please see our range of additional ducting outlets and digital controllers to enable a truly bespoke and cost-effective Marine solution.
\nMarine 12volt 4.0kw kit Contents:
\n\u2022 Webasto Air Top EVO40 self regulating 12 volt air heater with
\n\u2022 MultiControl HD 7-Day Timer with On-board diagnostics
\n\u2022 All electrical harnesses and connections
\n\u2022 1.8m Stainless steel exhaust silencer supplied with lagging insulation (measured lengths of 24mm stainless steel exhaust pipe are available if required)
\n\u2022 Copper Fuel pipe system, complete with fuel metering pump
\n\u2022 1 x Fuel Stand Pipe
\n\u2022 All necessary clips and screws for this installation included
\n\u2022 Comprehensive installation manual
\n\u2022 Stainless steel Heater mount bracket
\n\u2022 Stainless steel exhaust hull skin fitting
\n\u2022 Webasto Air Top EVO40 24 months warranty
\nBuy now from Butler Technik<\/p>\n
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Eberspacher Airtronic M2 D4 L 4KW 12v Diesel 2 Outlet Marine inc Easy Start PRO
\nOne of the best known makes of marine heaters, Eberspacher, has recently upgraded its Airtronic heaters, giving them a power boost mode for fast initial heating plus continuously variable temperature settings.
\nThey also now have a fresh air mode to improve air circulation through the boat on warm days.
\nYears of continual development has made these heaters more economical, quieter and more importantly, reliable.
\nThe wide range of controls on offer includes various panels with switches and LCDs, or there\u2019s the latest, EasyStart Call, which allows you to operate your heater using the proprietary smartphone app.
\nThe app turns your phone screen into a simulated control panel and transmits your selected settings to a GSM module installed in the heater.
\nModels include the Airtronic D2 and S2 D2L (<32ft LOA), D4+ and M2 D4L (26-39ft), D5 (36-49ft) and the D8LC (49-62ft).
\nBuy it now from heater parts direct<\/p>\n
Eberspacher Hydronic S3 HS3 Universal 5kW 17000BTU Vehicle Water Heating Kit including Easy Start PRO 12v
\nDiesel fired water heater with 5 kW heating power, for cabin interior saloon heating and engine pre-heating.
\nThe Hydronic can\u00a0 heat domestic hot water if coupled with a plate heat exchanger, hydroplate or calorifier.
\nThe kit includes
\nEberspacher Espar Hydronic S3 D5E CS
\nWater pump and fuel pump
\nEasy Start Pro Controller with 7-day timing and altitude switching
\nHeater wiring harness and electrical accessories
\nMounting bracket and fixing bolts
\nFeatures:
\nStepless modulated heating from 1.3kW up to 5kW depending on requirement.
\ndimensions: 215 x 91 x 144 mm.
\nSilent running fuel pump
\nThe Hydronic S3 Economy has a service life of 3000 hours. That\u2019s just over 8 hours a day for 365 days of the year!
\nBuy upgrade kit from Butler Tecknik
\nBuy complete kit from Butler Tecknik<\/p>\n
Note: We may earn a commission when you buy through links on our site, at no extra cost to you. This doesn\u2019t affect our editorial independence.<\/p>\n
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\nCommon issues are incorrectly designed exhausts, corrosive steel clips, screws and brackets, plastic fuel lines and filters, and non-watertight casings.
\nSome really cheap models lack thermal sensors, overheat alarms and shutdown modes, thereby presenting a very real risk of an onboard fire should the heat outlet accidentally be covered by a carelessly placed sail bag or drooping sleeping bag.
\nThere\u2019s also the possibility of carbon monoxide entering the boat if a fender is left dangling over the exhaust while the heater is running, or if the silencer is of poor quality with crimped, rather than welded seams.
\nAll these are very typical scenarios found on a cruising yacht and highlight the need for the appropriate, built-in safety devices listed in the regulations.
\nRecent advances in diesel forced air heaters
\nAs with most marine equipment, heating systems have been subject to gradual improvement over the past decade, both in regard to technical features and from a safety point of view.
\nMany are also now more economical on fuel and efficient on output, and the introduction of brushless fan motors has resulted in them using less electrical power and running much more quietly.
\nNew glow \u2018pins\u2019 rather than the older style glow \u2018plugs\u2019 have greatly improved fuel burn efficiency too and gone a long way towards eliminating \u2018coking up\u2019.
\nMany recent diesel heater models now have a boost function just to pre-warm the boat and an eco-setting in which it just ticks over enough to retain the temperature within a narrow range.
\nThere has also been a good deal of improvement in the controls.
\nIn the past they\u2019ve been simple electro-mechanical devices with either a rheostat or multi-way switch to select the temperature range.
\nThen along came more accurate controls with LCD displays and built-in seven-day timers.
\nNow, there are wireless remotes on offer and you can even control heaters by mobile app or online, so that you can switch the heater on when you\u2019re a few miles away and climb aboard a toasty boat whatever the weather.
\nHow much will a diesel forced air heater cost me?
\nIt\u2019s important to work out what you need for your installation before attempting to compare prices.
\nMost kits come with enough bits for a single outlet and the minimal amount of ducting. So, if you want two outlets, you\u2019ll need to measure carefully and price it in, along with a grill and a T-piece connector (\u00a360).
\nMany owners now fit silencers to the fresh air intake as well, to quieten the \u2018roar\u2019 heard with older models, plus anti- vibration rubber mounts to lessen the sound of the fuel pump are also available.
\nContinues below\u2026<\/p>\n
The cost can increase if you want a fancy controller, too.
\nThey usually come with just an analogue rotary-type knob with an LED or two to indicate operation status.
\nWhile this might suit some, others may want a remote panel with an LCD to show what\u2019s going on (\u00a3150- \u00a3200), or even control via their phone.
\nDon\u2019t be fooled by the \u2018free\u2019 app though, it\u2019ll only work if the heater is connected to the GSM network, and that involves buying a modem and a SIM card (\u00a3200-\u00a3300, plus around \u00a37.50\/ month for the SIM).
\nIf you get an advanced control box it\u2019s worth fitting a temperature sensor. Finally, check how long the standard control cable is, as an extension can sometimes mean it\u2019s cheaper and easier to opt for a wireless remote (\u00a3150).
\nMarine heater safety
\nMany of these heaters are designed for vehicles and don\u2019t always list a specific marine kit.
\nCheck the kit contains enough lagging to double-lag the exhaust and make sure the exhaust outlet is stainless or bronze and angled up to allow for a swan-neck in the pipe to eliminate back-feed of water.
\nIt is also worth double checking the kit is marine specific.
\nAutomotive heaters are designed to be fitted externally, so do not require the same standard of air-tightness on the joins around the exhaust and on the welds around the silencer.
\nSimilarly, metal fittings may be galvanised rather than stainless steel, and vulnerable to rust, and fuel lines not of the same specification.
\nThe critical safety issue is that of carbon monoxide.
\nA properly installed heating system will run without issue, but as we\u2019ve seen too often, an exhaust leak or other fault can be fatal.
\nAll boats should have a CO alarm anyway, but check yours is in date and working.<\/p>\n
FIREANGEL FA3820-EUX10 BATTERY STANDALONE CARBON MONOXIDE ALARM
\nBuy carbon monoxoide detector from Screw Fix
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\nThe post Best diesel heaters for boats \u2013 An expert buyer\u2019s guide appeared first on Yachting World.<\/p>\n","protected":false},"excerpt":{"rendered":"
The best diesel heaters for boats have seen some great improvements over the past few years. They’re the most common form of heating onboard sail boats and motorboats. Duncan Kent talks through the options and what to avoid. Best diesel … <\/p>\n