The BEST way to heat a garage gym or workshop

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Deep in the British winter I am now in full blown “must heat the garage” mode. Every time I step in to my garage gym I am reminded just how cold it can get in the UK… Global warming obviously not materialising in my postcode at the moment.

There are a few easy and cheap solutions to heat your garage gym, and even more complicated and expensive ones! Let’s run through all the options you can pick from when trying to heat your garage.

The best way to heat a garage gym or workshop

At a glance…

  • For most people insulating your garage gym or wearing more clothes will be enough to keep them warm
  • For the rest of us a simple electric heater will be sufficient
  • The Castle Heater NR15 is the best balance of power, cost and appearance for MOST people.
  • Plug-in electric space heaters are the cheapest and easiest way to heat a garage
  • In particularly cold climates, large or awkward spaces or where there is no mains electricity there are a vast array of alternatives available

Why do you need your garage heated?

What do you use your garage for?

This probably seems like a stupid question – but what all do you actually DO in your garage? And how does this impact your heating requirements?

Personally, I use my garage as a home gym as well as an occasional workshop space for miscellaneous car, garden and sport projects (rebuilding bicycles and such like). 

This means I need to be wary of open flames as I use various products when working on a car or bike that are flammable. I also need to avoid drying the air out too much as when exercising I don’t want to dry out my throat or skin.

Use a full blown garage gym? Then we need to make sure we know how best to heat it!
Use a full blown garage gym? Then we need to make sure we know how best to heat it!

How quickly do you need to heat your garage gym?

I also think the best way to heat a garage gym should be quick to warm up AND cool down – heading in to the home gym I’m often very cold initially but heat up pretty quickly once the weights start moving (or cardio starts flowing!) Often I will find myself wondering how the heck I would get through a workout as it’s so darn cold, then 10 minutes later I’m stripping off layers of clothing!

When do you use your garage?

When you use your garage should also be factored in. A summer user looking to take the edge off in a hot climate will have a MUCH different requirement to someone who works out year-round at night time in Alaska, USA!

What shape and size is your garage?

Garage gym heaters come in all shapes and sizes these days – the same as garages themselves. The shape of your space will impact what type of heater you need (e.g. L-shaped spaces have walls blocking the flow of heat), but not as much as overall size will. When thinking about this don’t forget HEIGHT! A high, pitched ceiling will draw heat away from your floor space as hot air naturally rises.

The size of the area you’re heating is one of the KEY pieces of the puzzle to work out what size of heater you need for your garage.

Other considerations

These are just a few examples I considered. If you are woodworking or anything like that in your space then you would need to think about the sawdust or other debris and whether that poses a fire hazard or could choke up any filtration systems.

Insulating your garage gym – probably enough for most

Before we look at trying to heat your garage gym UP, let’s take a look at what is cooling your space DOWN.

Most detached garages are glorified sheds – simple brick buildings, concrete floors with a thin, metal door. Even integral garages are often a basic brick design. This means any heat generated inside the garage is being conducted fairly quickly through the simple structure and radiating to the atmosphere outside.

Why should we pay to heat the outside world, and why would we want to?!

Luckily we don’t HAVE to do this. The (second) easiest way to heat your garage is by insulating it and keeping the hot air IN. Simply fitting a heat-containing layer of material to the inside walls and roof will work WONDERSat trapping heat and making your garage temperature more habitable.

How to insulate your garage door

Usually a thin, single-ply metal skin is all that sits between you and the cold, possibly wet outside world. Not to mention that metal is heat conductive meaning any heat disparity between your nice and hot garage gym will flow readily through the metal divider and disperse into the atmosphere.

Luckily insulating a garage door is a piece of cake. Simply pick up a roll of insulating material – or even easier a pre-cut kit – and stick on to your door. The material is metallic silver in colour, usually with a thin foam core. It’s light weight so sticking to a door is fine with no structural issues. Each product will attach differently but they all involve SOME kind of adhesive.

You may find the tape ultimately gives way and sags a little – simply reattach, or refresh the tape and you will be good to go for another few months.

In my honest opinion this is a fantastic heat saving technique, but it can look sloppy if you don’t take care when installing the insulation.

Foil garage door insulation - thin, lightweight and effective
Foil garage door insulation – thin, lightweight and effective

Insulating your garage walls

Each building will have its own nuances and – often, particularly if an older build – will be lacking insulation. How you insulate will depending on the construction itself.

For example if you have a timber frame with exposed struts you will likely want to buy rolls of fibreglass (or equivalent) insulation and pack this between the struts before tacking plasterboard or wood panelling across the struts. This will lock in the insulation and add a huge amount of heat retention to your space. The downside is the walls have closed in a little and it takes a bit of time to do!

If you have bare brick walls you get pretty awesome panels now that have a hard foam insulation layer, usually around 1.5” thick, with a plasterboard-style finished layer on top. You simply stick these to the brick. Again the downside is losing space in the room as the walls are closing in!

Insulating your garage roof

When looking to insulate your garage roof again consider the structure. If you have a large roof cavity with timber joists consider a false floor to mitigate the hot air rising in to the unused space. This even has the handy side effect of giving you a loft space for storage! Once closed off you can use the fibreglass rolls of insulation to pack between the rafters as we did to our walls previously.

Fully insulated & finished artex garage roof
Fully insulated & finished artex garage roof

Insulating your garage windows

Yes you read that right – you can insulate your windows! Use thick cling film or plastic to cover the window frame. This will trap a layer of air between the standard window and the plastic which will heat up naturally and act as a damper to any heat level fluctuations. It is the same technique in double glazed windows – just a more ‘rustic’ application! By using transparent plastic you don’t interfere too much with the flow of natural light either.

The negatives to insulation

Firstly, if you live in a particularly cold climate or somewhere with harsh winters then insulation alone may not be enough to get you comfortable in your home gym.

When looking to heat up the gym there will always be a downside… In the case of insulation it is the cost to do it. Up front you will need to buy all the materials and labour. Depending on the size of your garage it could cost quite a lot!

You won’t have the ability to control temperature closely – once installed there is nothing you can do beyond removing the insulation again or opening/closing your windows and doors. No thermostats in sight. 

This means you will need to be comfortable operating in a fairly wide window of temperature depending where you live – if you have hot summers and cold winters (something like our Canadian readers experience!) then insulation can’t be turned off for the sweltering summers. For those of us in a more stable climate (consistently bad temperature crew from the UK checking in!) insulation is a great choice.

Another downside is the cost profile – insulation is 100% front loaded meaning you pay for it up front with no ongoing cost. If you don’t have the cash to play today – then unfortunately ‘stay away’ (for now).

The positives to insulation

Insulation has no ongoing cost – once you install it and pay for that, there is no additional outlay required. This is great for those looking to control their ongoing costs or who simply don’t want to have to worry about it.

It’s possible to save some money by installing your own insulation – this is time consuming but within the abilities of most competent DIY’ers, particularly with some of the ‘one piece’ insulating panels mentioned earlier.

The other great thing about insulation is that it can ‘stack’ with other heating options which is handy for people in cold climates – if you have a well insulated space and you still want more heat then you will get away with a smaller, less powerful heat source. This saves you on purchase cost of the heater and reductions in the associated runnings costs.

Or you could try this…

Another option – one I rock day in day out – is simply dressing to the occasion. I layer up with thermals in winter, and change to shorts for summer. Is it perfect? Nope, but it works, it’s cheap and it doesn’t take much time to install…

Simple but effective way to keep warm in your garage gym - stick a hat on!
Simple but effective way to keep warm in your garage gym – stick a hat on!

How many BTUs do I need to heat my garage?

Heat output is measured in British Thermal Units (BTUs) and determining how many you optimally need will allow you to ‘right size’ your garage heater to your gym space.

Of course a smaller or larger heater will still function fine and heat your space, but you may find it takes longer than you’d like to heat up if it’s comparatively underpowered compared to your space, or find the heat overwhelming if it’s overpowered.

A quick rule of thumb calculation can give you a useful benchmark to work with. It could even save you a bit of money if you need a smaller heater than you would otherwise be tempted to buy!

To work out roughly how many BTUs you should be looking use this formula:

  • Square footage of your gym (width * length)
  • Multiply by 30 and, in a separate calculation, by 55 to get a useful range between the two figures

You then have a couple of bookend calculations (one at *30, the other at *55) to roughly work out your heating requirements in BTUs. If you stay in a warmer climate use the lower figure and vice versa. Similarly if you have a well insulated space then you can use this lower figure as a guide.

Electric space heater: Probably the best way to heat your garage

Space heaters are a great way to heat a garage gym. There are a TON of designs available and they come in TON of shapes and sizes. In fact, for most, a simple electric space heater is the best way to heat a garage, full stop.

Check out the Castle Heaters range here to find something to suit your space!

As we covered above insulation is really the first port of call, but a great second line in heating your garage is to add a simple space heater. This combines with your insulation to create a really warm, habitable working space.

Size matters

Just make sure you buy a unit with the right power output as covered above. I made the mistake of buying a few space heaters ‘off the shelf’ from B&Q which looked good, but they are way too powerful for my garage. I end up with a pretty serious level of heat and having to toggle it off and on frequently. It would be much better to have a smaller unit in terms of space, heat and cost. 

Some of the space heaters look very small and compact – but still pack a punch! As I mentioned I am guilty of buying ones that are too powerful simply as they looked beefier compared to some of the much smaller designs. But as we know – it’s not the size, it’s how you use it that counts! Make sure to use the BTU requirement formula above to guide you.

For balance, smaller heaters may be the ‘right size’, but the downside is that they could take longer to heat the garage gym space. This is not a big deal if you are fairly routine or organised and turn it on in advance of your workout – but if you want to jump in to the squat rack at short notice it might take a while to heat up with a smaller unit compared to a larger one.

Look at the size of this one: Tiny space heater!
Look at the size of this one: Tiny space heater!

Space heaters are portable – not just for the gym!

Heating a garage is handy, particularly if you spend a lot of time in there as a workshop or gym, but a benefit of space heaters is that they are very mobile – simply plug and play.

As mine are very powerful I don’t use them throughout much of the year – so I simply pack it away in storage. I recently had a boiler issue that knocked out my heating – I just pulled the heaters our and set them up in the house. Very versatile and handy to have around.

If you are lucky enough to have a large garage gym then you can even move the heater around – so warm up your squat rack area first, maybe move over to your deadlift platform after, and so on. Not jealous at all of those with that amount of space, nope…

Consider the shape of your garage as well – if you have an L shaped space or different levels or areas in there the heat may not travel well from a space heater around the full space. You might want two for this application – which obviously doubles all the costs.

Multiple designs available

One of the benefits of simple space heaters is there are a range of options available – from stand-alone radiator style flat panels (this is the style I have) through to very small units no bigger than a toaster (this is what I should have bought).

Most of these simply plug in to the mains and away you go. No installation costs and not time consuming to set up.

Radiator designs are slick

There are a lot of panel style electric heaters available – these can be free standing, wall or even ceiling mounted. They have the huge benefit of looking like a professional finish – really neat and tidy and keeping your valuable gym floor space clear. 

Radiator style electric heaters look really cool & integrate well into your garage gym
Radiator style electric heaters look really cool & integrate well into your garage gym

Downsides to electric space heaters: Power consumption

They use incremental electricity so if you run your heater a lot your bills will increase. This plays on my mind as I hate paying the electricity bill – but you may be more easy going than me 🙂

Fortunately with advances in technology modern electric heaters are energy efficient and comply with the latest standards – but they WILL use electricity (regardless of what the marketing data tells you!) Buying a heater with a thermostat control will help control bills as it will regulate the output from your device and stop it heating in a wasteful manner.

Of course they can only use electricity when they are plugged in and turned on… So if you are trying to heat a detached garage with no mains electricity they simply won’t be any use to you. Luckily there are some other choices below for you if that’s the case.

Downsides to electric space heaters: Fire hazard

By their nature these heaters look pretty friendly and unassuming, but they still get extremely hot in use. This can be a fire hazard in the wrong environment – for example could a draft in your garage blow some plastic wrapping off of a shelf on to your heater element, creating a fire?

Personally I wouldn’t leave an electric heater on in my garage when I wasn’t in there for this very reason.

Secondly if you have pets or children in the area they would need to be aware of this electric furnace quietly belching out heat! We definitely don’t want any burns as a result of trying to keep our gym a little warmer.

What other ways are there to heat your garage?

So a simple electric space heater is the best way to heat a garage gym for most people, but what about those who don’t want or simply can’t have one of these in their home gym?

Well luckily there are a load of other options, too! 

I would say these all have a sweet spot of where they work best, but generally they come with additional hassle and cost factor over a simple stand-alone, plug in electric heater and would be better suited to people in colder climates who will get the benefit of the heating regularly, or those with special circumstances or building requirements. 

Let’s take a look at all the other option to heat your gym:

Combustion or propane garage heaters

So what if you don’t have mains electricity, or simply don’t want to use an electric heater in your garage? Well there is the trust old propane heater which has been around for decades – and as such there is a huge range of models available in all shapes, sizes and importantly PRICES!

Propane heaters are a cheap, easy to use way to heat your garage. Similar to electric heaters discussed above there are a multitude of model designs available with various bells and whistles to help control and regulate your garages temperature.

Propane is quick to heat up your space, burns efficiently and is – crucially – cheap to fuel. This makes it a great option to consider if you don’t have mains power in your outhouse.

One downside to using a propane heater in your garage gym is that you need to be EXTREMELY careful to make sure your space is appropriately ventilated. Burning propane can throw off some bad smells and fumes – you will need a carbon monoxide detector to go along with your heater if you go down this route.

Propane space heaters: Not ideal for a garage gym
Propane space heaters: Not ideal for a garage gym

Personally I am not confident in household ventilation requirements so I gave the propane heaters a miss – you may be more experienced however and may be able to benefit from this cheap, plentiful heating source.

If using propane you will need to ensure you replenish your supplies of the gas from time to time via gas canisters. Electricity is much easier as you plug and play while with gas you will need to ensure you know where to get your propane canisters refilled locally and work out when to do this.

While propane heaters are plentiful and, putting the safety angle to one side, quite easy to set up they can be loud in use. They also add moisture into the air via their gas combustion process. Both of these points are key to garage gym users as you will likely not want a constant noise while you’re working out for an hour or two, and additional moisture will condense on your cold, metal equipment leading to rust. Those expensive squat racks and barbells might take a beating in a humid garage.

On balance I personally do not feel propane is a good way to heat a garage gym based in a standard UK sized space. It may be more useful in places like America where they tend to have more expansive house styles and plots with bigger gyms!

Ductless mini-split systems

Also known as a split system, or split-ductless system, ductless heating & cooling systems provide heating and cooling from a single unit. They are energy efficient and generally the most environmentally friendly heating option.

A ductless system is a pretty serious bit of kit with an air handling unit installed in your garage with a separate compressor mounted externally. The system is powered by electricity and the two parts are connected by a conduit which has various power cables, tunes and drainage connections needed which runs through your wall.

One of the great things about these is that the location for installation is flexible – it can be installed anywhere in your garage as long as it is on an external wall. These ductless systems are designed for these applications – heating different zones in or around your property in a controlled manner.

Let’s not beat around the bush – a mini-ductless system is a highly sophisticated solution with the costs to boot. 

Is it worth it? 

Possibly. This would be ideal in garage conversions or where you want your garage to feel like an extension of the house. Think remote control, accurate temperature control, thermostats, cooling options, the works. For those of us slanging some iron a few times a week this may be overkill. As these systems are designed as an extension of your living space they can take some time to heat up a garage from cold as they are designed with thermostatic control in mind.

Further, they are energy efficient and they do tend to look the best when installed properly. 

The negatives are that these systems are quite complex to install and as a result can cost quite a bit. There is also some maintenance required to keep filters clean and refreshed. They are also quite complicated beasts – so will need a specialist to help spec and fit. This could be an issue if you don’t have a specialist in your local area.

If your home varies in temperature that you would like to heat AND cool it, this may be worth further investigation.

So to conclude, a mini-ductless system is probably the best solution to heat a garage gym – but there are significant hurdles in the way! 

Infrared radiant heating options

Like radiators these radiant heating options are panels that warm up and then radiate their heat in to the wider environment. Technically pretty much any heater is a radiant one as they all spew out heat… But let’s focus on ones that are different to traditional space heaters covered above.

Infrared heater: Great choice
Infrared heater: Great choice

Infrared heater – step right up! Infrared heaters heat up objects before they heat flesh and blood. This is pretty amazing for garage gyms where the people tend to get hot and sweaty, but the apparatus like squat racks and barbells tends to keep a chill. This contributes to a very stable ambient temperature when working out.

Plus as they radiate the heat out they neither add excessive moisture nor dry the air out. 

They are an awesome alternative to a traditional air circulating heat system as the infrared bar simply emanates the heat out and in near silence. Similar to traditional options they can be powered by electricity, gas, propane – you name it. 

With the tendency to heat objects infrared heaters are the best way to heat a drafty garage as the ambient temperature loss is less severe than traditional space heating options.

The downside is that these heaters can burn if you rub against the heat tube, but this can be mitigated with some models available with a more aesthetic, hidden tube design. They cool down quickly when switched off which can be a good or a bad thing depending on how you use your space and heater. 

They are also harder to source and install compared to traditional space heaters, but once they’re in they are quite cheap to keep running.

Check out some of the best infrared heaters for the UK market here.

Ceiling mounted heaters

Ceiling panels are pretty rare, but have the massive benefit of being tucked up agains the roof properly out of your way. The downside is eating in to your headroom – this could be an issue if you are tall and like to do standing overhead pressing with full size Olympic plates on your barbell, or if you want to be able to chin-up in the space under the heater.

It is quite a specialised product and requires a finished ceiling to install on – so this is unlikely to be too popular in an average garage workshop or home gym.

Wall mounted heaters

A quick word on wall mounted heating options. In a garage gym space is at a premium – and often we are moving around with barbells or other weird, wonderful and oddly shaped objects!

In these scenarios a wall mounted heater pays dividends as they are as far out of the way as they possibly can be. There is nothing worse than bumping in to a loose space heater placed somewhere ‘it shouldn’t be’ when carrying a 20kg Olympic barbell. Ask me how I know…

Wall mounted options are fairly easy to hang yourself – they are very light and therefore can be hung like a picture frame in most cases. They also heat up quickly which is very helpful in a gym where you might jump in to the garage for an hour or so here and there instead of spending hours on end in the space.

Wall mounted heaters blend in to most spaces saving valuable floor space
Wall mounted heaters blend in to most spaces saving valuable floor space

The downside to wall mounted heaters is that they can struggle to fill larger spaces. This can be combatted by buying a heater with a fan built in to project the heat around the gym. 

Of course if you go for an electric wall mounted heater you will be constrained by one crucial thing… Sockets! And make sure to remember to switch it off when you’re done – like most electric heaters they can rack up electricity bills if not set up carefully.

Garage underfloor heating

Underfloor heating is one of the holy grails of household luxuries – I don’t have it, but I have experienced it and the warmth underfoot is AWESOME.

Is underfloor heating ideal for a garage gym though? In my opinion – NO. Underfloor heating involves pipe work embedded in the concrete slab, and in a gym that is subjected to heavy deadlifts I really don’t want any cavities in the slab which could reduce the structural integrity. 

The last thing I need is a cracked slab!

Forced air heating

Forced air heaters function by blowing hot air in to your garage. Their construction is fairly simple with a heating element which has air forced over it with a fan system. The heat can be provided by the ‘usual’ suspects – electricity, gas, etc. There is some ongoing maintenance required to keep filters and ducts cleared & in good condition, but it’s not overly onerous.

This has one major downside in that any circulating air can interfere with the environment – think dust circulating, messing up any paint work, etc. If you use your garage purely as a gym this is unlikely to be an issue, but for me where I often use it as a garage workshop this is a no go unfortunately.

Further the circulating fans can be noisey which may or may not annoy you if you’re in the gym for an hour or two!

The upshot is that forced air heating is FAST to deliver – it will rapidly heat your garage with delicious, warm and filtered air! 

This does come at a price though. They can be expensive to install depending on how you specify the unit and how much plumbing in will be required to get it installed in your garage.

Convection heaters

These use the natural flow of air to heat your garage – cold air is drawn in, heated up using a traditional heating coil and then the hot air naturally rises out of the top of the unit.

These can be pretty similar to the forced air heating covered above as some units use a fan to distribute air around the room quicker. This is handy in larger or oddly shaped garages where the heater might be quite far away from where you’re working out.

A stand alone convection heater - versatile option for heating a garage
A stand alone convection heater – versatile option for heating a garage

Like most electric style heaters convection devices come in all shapes and sizes – free standing, wall mounted, big, small, etc. and once set up they are quite easy to use.

The downside is that they don’t have air filters so they just recirculate any contaminants – unlikely to be a huge issue in a domestic setting, but one to watch if you also use your garage as a workshop or paint room. 

Sealed combustion heaters

One of the daddies of garage heating is sealed combustion devices. These draw air in, heat it up and pump it in to your garage space, expelling exhaust fumes created via an external exhaust.

These heaters are plumbed in to your gas line or can utilise separate propane tanks to drive them. The external venting means there are no undesirable fumes pumped in to your space like you get with traditional propane heaters (carbon monoxide = extremely dangerous.)

Sealed combustion heaters are ideal for workshops or when your space is more ‘room’ like. This works well in gym arrangements as obviously if you’re working up a sweat and getting out of breath we don’t want to be breathing in vast quantities of contaminated air!

The units themselves are mounted to a wall on the inside of the garage with the exhaust poking through the wall to the outside space. They have a combustion chamber where the gas or propane driven heating occurs and the air is circulated on the inside of the garage wall with the exhaust taking the combustion gases away

The downside is fitting is expensive and quite specialised, and they can only be used in areas that have an external wall. This makes them great for detached garages or gyms, but in most integrated spaces I would probably stick with the simpler and cheaper electric options.

Be careful with wood burning stoves!

Just a quick note to say installing a wood burning stove in your garage to heat your gym or workshop may have implications on your insurance. Be sure to check this out before doing anything!


It’s hopefully clear now that there are a TON of ways to heat your garage effectively and that the right choice will depend on your individual space, budget and needs. 

But, for most applications, I believe that a small plug-in electric space heater is the best way to heat a garage. When combined with well insulated walls, ceiling and door it will keep a good sized garage warm on a winters day in most climates.

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