Generally don’t! I know these are cheap heat, but why do you want a smelly nasty fume and condensation generator with all the hot work risks?

Try a dehumidifier first, on a time switch or ticking over in the background you’ll likely find it keeps the workshop adequately warm and dry with no handling of noxious fluids or risk of poisoning yourself.

Caveat, this does assume a reasonable standard of draught proofing and insulation.

I have just installed this one https://ban.ggood.vip/1mkFF

It comes with all the fittings and is mains powered. Good price too. Ships from UK.

Comes with remote control with 30m range so you can heat up the workshop before you go out there.

Exhausted to outside. No smell.

Advantage:  perceived cheap heat, probably true if commercial diesel is available, and a lot is burned.  Maybe kudos for being a brave installer.

Disadvantages:

• Requires an external exhaust pipe, holes in the wall, and protecting the outside so passers-by don’t get burnt and ensuring fumes don’t get back into the house.
• Has to be fitted, and the workshop arranged, so that it cannot start a fire.
• Intended for use in vehicles, and the fitting instructions do not cover buildings
• As a fixed installation, may infringe building regulations.
• Unlikely to be covered by building insurance.
• A tankful of diesel, with pipework, is a spill and fire hazard inside the workshop
• Ideally requires ducts to distribute hot air around the workshop
• More work than I like, and some of it iffy.
• Does the installer know what he’s doing, or is he taking unbounded risks?   (ie risks he doesn’t know exist, or doesn’t know how likely they are to occur, or what the consequences will be?)
• May not be cheap when the installation time and cost are added.

Are you an optimist or a pessimist!  I was trained to cover specified requirements by thinking them through more-or-less formally, and to defer choosing the answer until the important pros and cons have been identified.  All options are considered, even apparently bonkers ones!  Training has made me a pessimist unsympathetic to cheerful bodging, even though JFDI is delightfully quick!   Unfortunately, JFDI also tends to produce solutions that are out-dated, high maintenance and inefficient, costing a fortune in the long run, and snuffing out innovation.  Bodgers are rarely self-critical.

Defining requirements is particularly valuable when tackling anything new because experience may be completely irrelevant.

So what exactly is the requirement?  Is it to simply keep the operator comfy or is rusting a problem?  Is the workshop a poorly insulated shed, or part of the house?   Does cost matter?

I’m not suggesting anything complicated, 30 minutes thought, resulting in a short prioritised list of needs.  When I analysed my requirement for sharp milling cutters, I found the answer isn’t a Quorn! A lot of cutters have to be sharpened to justify one. My modest requirements mean a Quorn is a complete waste of time and money, even though it’s an excellent bit of kit.

Diesel heating is just one of several options.  Have any other options been considered, and why were they rejected?  Diesel heating wouldn’t be a bad mistake in my workshop, but it’s not right for me because I have a well-insulated workshop attached to the house and some of the disadvantages above are too salty!   Instead I “do nothing” and wait for the lights and motors to take the chill off, or, I give the workshop a quick blast with a fan heater.  Also wear warm clothes.     Works for me, might not be good enough for you!  Your requirement is different, therefore look at alternatives.

Dave

I’ll double up on Robert’s comments.

Most (well, nearly all) youtube “installers/users” are plain idiots.  Most demonstrate just how/why they should not be installed!  CO is a killer. Chinese exhaust materials are poor.   Many get away with it but if there was ever a mishap they would bear all the fault themselves.

Most people only die once and you are a long time dead.  If one is fitted inside a house and there was a fire, one’s insurance company would likely invalidate the fire insurance even if the cause was not the heater!  Be warned.

They are safe if properly installed – as a <u>parking</u> heater.  Otherwise unsafe.

There is one sensible guy, on youtube, who warms his house by siting the heater outside and venting the warm air through the wall.  Obviously a little less efficient but safer.

I’ve been running one for a few years now in my workshop, the heater is mounted on an external wall inside ‘leanto’ shed. It drawers air in from high level through the wall into heater and blows it back in at lower level in a couple of places.

I run it on kero (heating oil as we have that anyway for house heating) and after running it constantly for 3 – 4 months each winter on it’s lowest setting with occasional high setting to help keep burner clean I stripped it to clean combustion chamber and service it but other than coloured inside the chamber, cleaning was not needed.

The exhaust pipe is about 2.5m long through a stainless marine exhaust fitting (ebay cheap) through the shed wall, the exhaust is very thin but is stainless and fits really well on to the heater outlet so with a bit of exhaust assembly paste there are no leaks – tested with a CO monitoring ‘wand’. The bonus is the high level of wasted heat form the exhaust heats the shed nicely!

I have a CO monitor above the outlet in the workshop and it’s never read anything other than 0.

My workshop is single skin block built wit traditional ridge roof. it is relatively draft free and I have insulated the roof with 2″ celotex which made a huge difference, the heater keeps the temperature reasonably comfortable for about 2.6L of heating oil for 24 hours running so not that cheap (60 odd pence per litre). I have a few fixed automatic powder extinguishers in there, 2 6KG in the main workshop and 1 directly over the heater installation as well as portable stuff.

Since fitting I have had to do no rust prevention on any of my kit, it’s reasonably comfortable to work in there when it’s minus 2 outside.

There are some pics of it in a thread about these heaters on here somewhere.

Would I fit one inside my workshop? I doubt it.. fit it in a box outside.

Is it worth fitting without any other measures to draft proof & retain the heat? Not unless you have access to a free fuel source!

I love mine though and the whole installation cost me about £100 with the power supply but I did get the heater cheap as after complaining they sent me the wrong controller with it, not as advertised, so had about 40% discount. You could probably do it with power supply for not much more now that the heaters are even cheaper and don’t fall for the ‘8KW’ versions etc, they are identical in every way to the 4 – 5KW versions – as David McLuckie has shown on his youtube channel.

They are so basic there isn’t much to go wrong with them and parts are plentiful. If your switched on enough to understand the risks and treat them with the respect they deserve then I don’t see a problem.

On 2 October 2025 at 17:37 not done it yet Said:

On 2 October 2025 at 08:01 Tony Pratt 1 Said:

What’s wrong with an electric heater?

Tony

Taf says he uses about 2.6 litres of oil per day.  That is roughly 26kWh.  Taking 70% efficiency gives 18kWh which could cost taf over £4.50 each day, if on the current energy price cap rate.

That’s why it’s not viable for taf to heat with grid electricity!  YMMV.

Good to get figures and context, so thanks to Taf and NDIY both!

Taf has oil heating already, so he probably buys oil by the ton at 5% VAT, the cheapest way of buying it legally.   If he powered his heater with DIY store paraffin, it costs nearly £3 per litre, which is more expensive than electricity.

For my heavily insulated and almost totally draught-proofed 35 m^2 workshop, I run a small desiccant dehumidifier for a couple hours per night.  It runs on a 8.5p/kWh tariff so costs around 6 1/2p per night.  That is sufficient to avoid condensation for most of the UK winter.  I run it longer, or on higher power, when 2 hours is insufficient.

I don’t even need a dehumidifier, luck not judgement.  Could be the difference is due to the way our workshops face.  South side of my home is much warmer than the North.   Taf mentioned in another thread that his workshop is exposed on the Welsh coast, and it’s a thin walled lean-to.  It will take a lot of heating.  Best to upgrade the insulation if possible; it works out much cheaper than oil, gas or electric heating in the long run.

I generally only use extra heat before and while in the workshop.

Me too, only to take the edge off on very cold days.

Taf also mentioned installation cost, £100 in his case.  That also has to be factored in.   An electric fan heater can be had for £10.   Electric offers more choice: a fan heater warms and churns the air, and is good for breaking the ice.  A radiant heater warms what the radiation bumps into, which helps reduce condensation.  A convention heater warms the air gently, which is good for long term heating, slowly warmed damp air being less likely to condense on metal.

Bottom line, diesel heaters aren’t necessarily the right answer, even if oil is cheap.

Oh, and watch out for faulty logic resulting from chaps saying Carbon Monoxide isn’t a problem in their experience!  Their experience doesn’t pass the “so what test”.  A sample of one, context unknown, is meaningless and CO only kills a small proportion of users.  26.1 deaths per year in the UK, though the figure is believed to be “the tip of the iceberg”.  Usually due to incorrect fitting, poor maintenance and faulty materials.    Third-party experience is low value in this example: it’s your installation that will get you, not his!  Ditto the fire hazard.  You are responsible for getting safety right, not the internet!

Dave

Oops! My workshop is ~35m^3, not m^2.

It’s the heat as well as the dehumidification that keeps it well above dew point.

Most say use a cheap chinese power supply but I strongly disagree and consider it poor advice.

I always recommend a battery + float charger as the power supply.  If the mains goes off while the heater is running (so no cool-down cycle) the motherboard in front of the now stationary fan will be subjected to heat from the burn chamber and could fail the first time it happens.  Also once stopped, due to a power outage, it ain’t going to restart.  Depends on what risk you wish to take.

When I go away, say for a week, I leave two dehumidifiers running on shorter times.  Likely only one would fail (both are cheap second hand (repaired) Meaco dehumidifiers which were not the most reliable) and twice the water volume (if no drain is installed).  I usually only collect about a litre and a half weekly, if that, I think.  Depends on run time, weather, temperature changes and whether the floor is totally damp proof, etc.

Rusty tools/machines are never quite the same and/or need a lot of input to rectify. Belt and braces is better!

Unfortunately the people who are killed by carbon monoxide arn’t here to tell us when it went from “no problems what so ever ” to death.
Even with the heater outside a crack in the heat exchanger or other leak can still put CO into the occupied space.
If using any kind combustion heater in the workshop you MUST HAVE A CO ALARM.

I’m pretty hard over on this one for a number or reasons. Two are awareness of the number of deaths caused by similar heaters on aircraft and becase a relative of mine was killed by CO from a gas heater.

Robert.