Are your greenhouse plants failing to thrive, despite your best efforts? This is a complete guide on picking the right heater for your greenhouse. Below we have a quick table linking you to the individual review type on this page, as well as a link to it on where to buy.
No matter how green-thumbed you are, your plants won’t reach their full potential if they don’t have the light and heat they need. Considering our dreary British weather, this can be quite the problem for hobbyist and professional gardeners alike!
Luckily, there’s a simple solution: greenhouse space heaters. This simple, unassuming appliance can make a huge difference in your gardening efforts by preventing frost damage, improving air circulation, keeping your greenhouse at a steady temperature and ensuring you’re feeling nice and toasty when tending to your plants. Best of all, they shouldn’t cost the earth to run, even with the current cost of living crisis.
In this helpful guide, I’m going to introduce you to the four main types of greenhouse heaters (electric, paraffin, propane and solar) and walk you through the best options I’ve found in each of these categories. Then, I’ll give you some extra tips and tricks on how to insulate your greenhouse so you can get the most out of your greenhouse heaters.
Let’s get to it!
Greenhouse Heater Buying Guide for Beginners
Sometimes, too much choice can be a bad thing, especially if you have no idea where to start. There are so many greenhouse heaters on the market, making it difficult for beginners to find the right product for them.
If you’ve never bought a greenhouse heater before, then you’ve come to the right place. Below, I’ll highlight the four main types of greenhouse heaters and let you know the pros and cons of each one. All you’ll have to do is pick your favourite!
For most gardeners, choosing an electric space heater is a bit of a no-brainer.
This is because electric heaters have superior heating capabilities and are extremely easy to use. Many electric heaters come with different heating modes, easy-to-use thermostats and timers, making it super simple to set a consistent temperature in your greenhouse and not have to constantly fiddle with the settings. However, please be aware that you can’t leave your greenhouse heater completely unattended – this can be a huge fire risk!
Not only are these settings and built-in thermostats extremely convenient for busy gardeners, but they’re also vital if you need to keep your plants at a particular temperature. You won’t find this level of customisation with other greenhouse heaters, so as long as you have an accessible (and waterproof) power outlet near your greenhouse, you can’t really go wrong with the right electric greenhouse heater in UK weather.
Higher-end greenhouse electric heaters will easily go up to 2kW, which means they can heat larger greenhouses with ease, or make your small greenhouse very toasty indeed! Electric heaters also don’t produce any nasty fumes, which is a definite upgrade from older gas or petrol-based heaters.
However, one thing you’ll need to consider is heat distribution. Your greenhouse heating solution should also ensure that heat is distributed evenly throughout the space, allowing all plants to benefit from the heat and preventing temperature shock in plants exposed to fluctuating temperatures. Greenhouse electric heaters can sometimes be inferior when it comes to heat distribution, but higher-end models often have fans that boost air circulation. Or, as a quick fix, you could place two cheap heaters at either end of your greenhouse for consistent heating.
Another issue you may run into is the overall cost. There are plenty of more affordable electric heaters if you’re feeling the pinch (although they won’t have as many features), but with the current cost of electricity, the running costs could soon start to mount up.
If you’re a gardening traditionalist (or just want a bit of a bargain), a paraffin heater could be the right choice for you. Due to its low cost, longevity and smaller heating capabilities, a paraffin heater could be the best heater for greenhouse heating on a smaller scale.
As the name suggests, paraffin heaters run on paraffin fuel instead of electricity, which means you won’t have to plug this heater into a power outlet or worry about electricity costs. Instead, all you’ll need to do is refuel the tank with paraffin when needed and place the heater on a flat surface with plenty of space around it. Simple!
Another benefit of using a paraffin heater is that it produces carbon dioxide for your plants, giving them the fuel they need. Of course, you’ll need to ensure that your greenhouse is adequately ventilated if you use this type of heater – the fumes certainly aren’t as beneficial (or pleasant to smell) for humans!
Paraffin heaters are perfectly adequate for hobby gardeners with smaller greenhouses, but you may find the higher level of maintenance quite annoying. Unlike an electric heater, a paraffin heater won’t come with a built-in thermostat or easily adjustable settings. Instead, you’ll have to adjust the wick manually to provide the right temperature, and it’s unwise to leave this open flame unattended due to the potential fire risk.
Next, we have gas heaters or, more specifically, propane heaters. This is another affordable and small greenhouse heater that doesn’t rely on electricity, making it a great option for those worried about electricity costs.
Like paraffin heaters, propane greenhouse heaters simply need to be refuelled when necessary and kept on a level surface. Your propane heater will get very hot throughout the day, so give it a bit of space to prevent accidents.
Again, make sure you ventilate your greenhouse properly if you use this type of gas heater. You can get some nasty fumes from a propane heater, so you shouldn’t be breathing them in! Let the plants have some CO2 and ventilate the rest.
A new and exciting technology that’s on the rise is the solar greenhouse heater. If you want to reduce your carbon footprint and lower your energy bills too, then a solar heating system could be the perfect solution.
Unfortunately, I haven’t yet found an all-in-one solar-powered portable heater, although this technology could be with us soon. Instead, if you want to use solar power for your greenhouse heater, you’ll probably have to buy a solar panel kit that you can connect to a regular electric greenhouse heater to run it with solar power.
Setting up this heating system might be a bit more difficult at first, but then you can benefit from free and clean energy for your greenhouse. To get started, you’ll need a kit with a photovoltaic (PV) solar panel (usually a monocrystalline one because these are more space-efficient and energy-efficient), a charge controller and a 12V lead acid battery. The battery will store solar power from the solar panel so it can be used at any time, not just when the sun is shining. The charge controller will connect to the battery and solar panel to prevent the components from becoming damaged.
Finally, you’ll need to connect your set-up to an electric heater to create a solar heating solution. To keep things simple, you can use a 12V DC (direct current) electric heater and connect it straight to the solar system. Or, if you have a generic 250W AC (alternating current) heater, you’ll need to connect it to a DC/AC inverter to convert the power to AC for your greenhouse electric heater.
Don’t worry – this sounds more complicated than it actually is! Once you have the initial set-up sorted, your greenhouse solar heater will provide clean and free heat energy for your plants, without any dangerous fumes, open flames or eye-wateringly high running costs. The only downside is that your solar panels won’t create and store energy at night or on very cloudy days. This could be a potential problem during winter months (or even summer months) in the UK!
Tried and Tested: The Best Greenhouse Heaters for UK Gardeners
So, now you know the basics, you’ll be wanting to know more about where you can buy the best electric heaters, paraffin heaters, propane heaters and solar heaters for your greenhouse.
Well, you’re in luck! I’ve compiled a list of the best greenhouse heaters for all situations, including heaters for small greenhouses, large greenhouses, busy gardeners and hobbyists.
Keep reading to discover the best of the best!
Best Electric Greenhouse Heater Heaters
Best Paraffin Greenhouse Heaters
Don’t fancy an electric heater? If you’ve just got a small greenhouse and you’re hoping to keep the frost at bay, a small paraffin heater could be all you need.
Best Gas Greenhouse Heaters
Best Solar Greenhouse Heaters
Finally, let’s have a look at solar heating for greenhouse plants.
As mentioned before, it’s currently difficult to find a standalone solar-powered greenhouse heater, although this technology is likely to develop quickly in the coming years. In the meantime, you’ll have to set up your own solar heating system with a solar panel kit if you want to heat your greenhouse with solar energy.
Is Running a Greenhouse Heater Time-Consuming?
Unfortunately, running a heater can be time-consuming. However, this will all depend on the size of your greenhouse, your plants, the type of heater you have and how many heaters you have, so don’t fret – you can make this process as easy as possible!
Paraffin and propane heaters can require more maintenance due to the need to refuel, and paraffin heaters need to have their wicks adjusted manually to control the temperature. With solar greenhouse heaters, the initial set-up can be quite time-consuming as technological limitations mean that you need to install a full solar panel kit with a battery. As a result, all of these heaters can be fairly time-consuming to run.
However, after the initial set-up, solar heaters will run well without too much oversight. Similarly, traditional electric greenhouse heaters require little maintenance, although both of these options are usually more expensive.
Ultimately, you need to balance cost and convenience. Electric heaters can be more expensive to buy and run, but since they’re more powerful and much less time-consuming, they may be worth the investment, especially if you have a larger greenhouse to manage. Hobbyist gardeners with small greenhouses may prefer to cut costs and go for a little paraffin heater that can keep the frost at bay – do what seems best for you!
How Noisy Are Greenhouse Heaters?
It may not be the first thing on your mind, but noise is definitely a factor you should consider when buying a greenhouse heater, particularly if you have neighbours close by.
Generally, hobbyist gardeners with small greenhouses don’t have to worry too much about this, as paraffin heaters tend to not produce much noise at all. On the other hand, gas and electric greenhouse heaters do produce a bit of a humming noise when switched on, which can be amplified if they have a built-in fan for air circulation.
Ultimately, you won’t have to be too concerned about noise if you just have one heater in a small greenhouse, even if this is an electric or gas heater. Problems may arise if you have a large greenhouse with multiple heaters, so if you have close neighbours, make sure you bear this in mind. You don’t want your greenhouse to cause a neighbourhood dispute!
The Best Greenhouse Heater Alternatives
If you’re looking for convenience and effectiveness, you really can’t beat a high-quality electric heater, paraffin heater, propane heater or solar heater for greenhouse heating purposes.
However, if for some reason a greenhouse heater isn’t the right fit for you, there are other ways you can heat your greenhouse and keep your plants happy. A greenhouse that doesn’t need a heater is called a passive solar greenhouse.
Here are some of my favourite alternative greenhouse heating methods for passive solar greenhouses:
- Repair any cracks and gaps around your greenhouse to prevent heat loss.
- Clean all of the windows to let more sunlight in during the day, which will trap heat inside the greenhouse all day and night.
- Insulate your greenhouse with bubble wrap – the air pockets are fantastic for trapping heat in, and the clear material ensures that sunlight can still get through. Make sure you don’t cover the entirety of the greenhouse though because you do need ventilation too!
- Insulate the foundations of your greenhouse with a ‘Swedish Skirt’. Heat loss can also occur through the floor, so insulating the base of your greenhouse can actually make a huge difference. To create ‘Swedish Skirt’ insulation, you just need to dig out some of the soil around your greenhouse to create a slope, and then place rigid foam boards around this slope, extending 4 feet out from the base of your greenhouse. This traps geothermal heat under the structure to keep it warm and toasty.
- Use the quick and easy thermal mass trick with barrels of water. Thermal mass is the capacity of a material to absorb and release heat.
- If you place black containers filled with water around your greenhouse, these items will absorb heat throughout the day and then slowly release this heat at night, helping temperatures stay high enough when there isn’t any sunlight. If you have a small greenhouse, you could grab some 1-litre plastic milk bottles, paint them black, fill them with water and place them around your plants for a quick and easy DIY solution.
- Move your compost heap to the greenhouse. You can put your compost in a large black drum or dig out trenches in the floor for the compost. The chemical breakdowns occurring in the compost will release heat for your plants.
- If specific plants need more heat than others, you can invest in a couple of small heat lamps rather than heating the whole space.
- Cover your greenhouse with a large sheet or sheets at night to trap heat inside. You can also cover your plants with a blanket at night if you’re expecting very cold conditions, but be careful not to crush them!
All of these tips and tricks can help you create an effective passive solar greenhouse, as long as the weather isn’t too cold and frosty. However, it can get pretty cold in the UK at certain times of the year, so you may not always be able to rely on these heating hacks.
To ensure that your plants can thrive in this climate, it’s best to purchase a greenhouse heater that suits your needs. Then, you can use these passive solar heating tips to insulate your greenhouse as well as possible and reduce your reliance on your heater, helping you save an extra bit of cash on running costs
Final Thoughts on Finding the Best Greenhouse Heater
Greenhouses are essential for extending the growing season and allowing UK gardeners to tend to their plants no matter the weather. As long as you have a warm, well-insulated greenhouse, you can garden to your heart’s content all year long.
Although there are many passive solar heating tips to keep your greenhouse naturally warm, sometimes you need a helping hand from greenhouse heaters, especially during the winter months. Electric greenhouse heaters, gas heaters, paraffin heaters and solar greenhouse heaters are all brilliant options, but the best one for you will depend on your personal circumstances and needs.
To discover your perfect heater for greenhouse use, check out my list of recommendations earlier in this article. No matter the size of your greenhouse, your budget or the plants you’re growing, you’ll be able to find a greenhouse heater that ticks all your boxes.
For now, greenhouse electric heaters seem to be dominating the market due to their convenience, efficiency, power and safety, but it will be interesting to see how the solar-powered greenhouse heater takes over in the future. The development of this clean, eco-friendly technology could be revolutionary for the gardening world and all other industries, so let’s see what happens in a few years’ time!
I’m Chloe, the founder of this site. I was literally born with green fingers and have been into all things gardening since I was a little girl. Gardening is my passion as you can see from the TON of content I’ve published on my site. Thanks for checking out this post but please also take a look around the site to see what else might pique your interest. P.S I am *always* looking for helpful feedback, so if you have something you would like to suggest or just wanna say hi – drop me a message – firstname.lastname@example.org, don’t be shy!