As plant devotees you’ll know the importance of keeping your plants at an ideal temperature. However sometimes your climate just isn’t doing what you need. For your plants to thrive, or even survive these bad weather conditions, you’ll therefore need to be able to provide a stable and warm environment. The easiest way to do this is to use a greenhouse heater. Nevertheless, choosing one out of the hundreds or even thousands on the market can be an overwhelming or, frankly impossible, task without a little help. We’ve put together a list of 5 best choices of greenhouse heaters. This includes the best overall, one for people on a budget, the best electric heater and more.
For our top choice overall we’ve chosen the Big Buddy portable propane heater. It’s efficient, it’s reliable, it covers a large area and it has three different heat settings! The heater also has built in safety features including an automatic shut off if the heater is tipped over or accidentally falls. As well as an automatic low oxygen shut off system to ensure safe usage. The Big Buddy heater is a worthy investment for any greenhouse owner looking to keep their plants thriving during temperature changes, frost and winter seasons.
- Best Overall: Big Buddy Heater
- Best Affordable: Buyplus Fan Heater
- Best for Small Greenhouses: Dr.Heater DR218 Infrared Heater
- Best Electric Heater: Bio Green Palma Heater
- Best Heater for Temperate Climates: Pelonis Portable Space Heater
Product Reviews
Best Overall: Big Buddy Portable Propane Heater
Coming in at our number one pick, the Big Buddy greenhouse heater is one of the best heaters on the market. It covers a large space and in fact boasts three heating options. This is a great bonus as the high, medium and low settings allow you to customize the environment to suit any plant. The heater is marked for indoor usage and it doesn’t require any additional ventilation. It also has an automatic shut off in case of low oxygen levels or if the heater falls over for the added peace of mind and safety.
The heater in fact can run for up to 11 hours on low and 2.8 hours on a high setting. It has a heavy-duty wire guard as well as an easy-grip handle and piezo ignition. A piezo ignition system is great because they are built to last, generally for a minimum of ten years. As well, the ignition element is protected within the ignition tube, which makes it more reliable than mounted igniters.
Key Features:
- Power Source: Propane
- Heat Output: Between 4,000 and 18,000 BTU (the medium setting emits 9,000 BTU)
- Area Coverage: 450 square feet coverage for up to 11 hours with dual tanks on low setting
- Specifications: 17” x 10” x 17”
- Weight: 16lbs
| Pros | Cons |
| Quickly provides heat to the area | It doesn’t have a fan to distribute the warm air |
| Suitable for indoors and outdoor usage | No thermostat control |
| This heater can be connected to larger gas tanks or a remote supply | By far this is the most expensive of the heaters on the list, about twice the price of the next more expensive one and five times the price of the cheapest heater |
| Has safety features of auto shut off |
Best Affordable: Stanley Electric Greenhouse Heater
The Stanley heater is a small, portable and affordable option for heating greenhouses and patios. The heater has three settings, fan only and then a low/high temperature setting. The fan only setting is ideal for when you want to boost ventilation but it’s already warm enough (like throughout summer). As this heater is an energy efficient device it is more cost-effective to run compared to propane heaters. The Stanley electric heater also has an automatic shut off which is triggered when the ambient temperature reaches a certain point or if the device itself begins to overheat. It’s also extremely compact which makes it super easy to move, meaning you can utilize this device in lots of areas of your home or around your greenhouse.
Key Features:
- Power Source: Electric (Fan and forced air)
- Heat Output: 1500 Watts
- Area Coverage: 165 sq feet
- Specifications: 7″D x 10″W x 12″H
- Weight: 3.78Ibs
| Pros | Cons |
| Super affordable (compared to other heaters) | It has a smaller coverage so wouldn’t warm a larger greenhouse very effectively. |
| Very quiet to operate | No thermostat control |
| Compact and energy-efficient | |
| Effective at maintaining a set heat |
Best for Small Greenhouses: Dr. Heater DR218 – 1500W Greenhouse Heater
This heater is the perfect small greenhouse heater. Dr Heater greenhouse heater is reliable and efficient, with its fan-forced air technology you can ensure the best temperatures and environment for your vulnerable plants. This heater is a dependable tool to keep your plants from freezing, or getting frost damage (in the cold-weather seasons). The Dr. Heater greenhouse heater has precision temperature settings, which is ideal for plants with very specific needs to thrive. Additionally, this heater is super easy to keep as it requires very little maintenance. This is thanks to its heavy-duty steel casing and water-proof exterior. These features also mean the heater will last you for a long time, ensuring you get your money’s worth! It has an adjustable thermostat and automatic overheat protection built in, for that little bit of extra safety, as it will shut off if anything goes wrong, so you’re protected.
Extra bonus, as the fan blows warm air for longer periods of time instead of hot air for less time, it prevents your plants from overheating, going crisp or drying out. If your plants start to look wilted or dry it might be worth using a humidifier in conjunction with your heater.
Key Features:
- Power Source: Electric (Fan and forced air)
- Heat Output: 10,230 BTU
- Area Coverage: 240 square feet
- Specifications: 15” x 10” x 10”
- Weight: 13lbs
| Pros | Cons |
| Effective at keeping small greenhouses warm | Smaller area coverage makes it less suitable for larger greenhouses |
| Super portable as it is small, lightweight and easy to move around | The thermostat only has a temperature dial, and you can’t set it to a specific temperature |
| It has a good quality fan, enabling its heavy heating abilities | Only one setting of power (1500W) |
| Durable all-metal casing |
Best Electric Heater: Bio Green Palma Greenhouse Heater
The Bio Green Palma Greenhouse Heater is a durable, energy efficient electric heater which is perfect for heating small greenhouses, sheds, garages etc. The main body of the heater is stainless steel, which makes it robust and long-lasting. Additionally it has a floor-standing design, keeping the body of the heater elevated from the ground, preventing cosmetic damage. It has a digital thermostat, allowing for precise temperature control, as well as an external sensor cable to ensure accurate and consistent temperatures. On top of that, the Bio Green heater is compact and portable, plus it has a non-slip rubber base so that it is easy to adjust and position where you want it.
The best thing about this particular heater is that the technology behind the Bio Green maintains a consistent temperature throughout the greenhouse. Rather than simply heating for a set time, it monitors the temperature and adjusts in order to avoid energy wasting temperature peaks and troughs. This subsequently guarantees frost protection. The heater has various fan settings which can circulate hot or cold air effectively, so it is useful year-round to protect your plants from extreme temperature changes.
All in all, the Bio Green Palma Greenhouse Heater is one of the best electric heaters on the market. It is also a great choice for anyone with a small greenhouse who is in search of a reliable and energy-efficient heating solution.
Key Features:
- Power Source: Electric (Fan and forced air)
- Heat Output: 5,118 BTU
- Area Coverage: 120 square feet
- Specifications: 12.5” x 8” x 11”
- Weight: 10.8lbs
| Pros | Cons |
| It is super effective at keeping a small greenhouse warm during winter or cool during the warmer weather | The thermostat accuracy will never be 100% and may require manual adjustments |
| It has a thermostat which helps to ensure constant temperatures and less fluctuations | It has a smaller area coverage won’t effectively heat larger greenhouses |
| It is super easy to put together | It is on the pricier side at $150 |
| It has a sturdy base and generally durable materials |
Best Greenhouse Heater for Mild Climates: Pelonis Oil Heater
Whilst oil-filled heaters are primarily used in indoor spaces for heating, they are actually the perfect greenhouse heater if you live in a mild climate with more temperate conditions. Even though you might not have extreme warm or cold conditions across the seasons, your plants may sometimes need a little extra ambient heat to keep them happy. The Pelonis oil heater provides enough ambient heat to protect plants from frost damage for when the temperature takes a dip below 32ºF.
The Pelonis portable oil heater has three power settings and runs on electricity to heat the oil inside of the heater. The heater turns off automatically when the oil inside of the heater has become hot enough to radiate heat to the surrounding area. This setting is perfect if you aren’t going to be constantly around to monitor temperatures and manually turn your heaters on or off. It also allows for a little extra security as there is a much smaller risk of fires from overheating, thanks to its automatic shutoff. The Pelonis oil heater is particularly perfect for the job of greenhouse heater, compared to many other oil heaters, because it also has a fan built in to circulate the warmth and hot air around the space.
Key Features:
- Power Source: Electricity
- Heat Output: Three modes available, high, low or eco, with maximum usage being 1500 watts
- Area Coverage: 230 square feet
- Specifications: 14.17” x 11.02” x 25.20”
- Weight: 19.75lbs
| Pros | Cons |
| This heater has multiple safety features including a tip-over switch and an overheat auto shutoff so you can leave it running unattended without needing to worry about fire hazards. | Some reviews suggest the heater is a little slow to heat up and then it puts out a lot of heat |
| Cost-effective, it doesn’t have a massive impact on electricity bills and is affordable to run | This heater beeps loudly once when turned on |
| Super quiet to run (the listing states that it is completely noiseless but some of the reviews suggest it tends to make some noise but not a disruptive amount | This heaters emits a slight odor at first, however this is totally normal |
| The whole heater is made of or encased in fire-resistant materials |
Buying Guide and What You Should Know
A greenhouse is obviously intended to provide shelter from the cold, rain, snow and wind during bad weather seasons. However, when the temperatures drop far enough, even the best greenhouses need a little help. A heater for your greenhouse can help keep your plants alive through the winter, preventing the damage done by frost and rapid temperature fluctuations. Even if the cold doesn’t kill your plants it can slow their growth, damage their foliage, reduce flowering and affect your yield. It’s important to choose the right heater for your space and plants. You run the risk of getting more heating power than you need, and paying extortionately for high energy bills, or getting a heater that’s not powerful enough to fill your space. Overheat and your plants will pay, underheat and you’re wasting money without the benefits!
To make such a complex decision it’s important to consider many factors.
Size of the Greenhouse and Heat Output
You’ll need to consider the size of your greenhouse, how much space you are trying to heat and how effectively that space can keep in the heat. Ideally, you’ll need to know the size of your greenhouse (the surface area of the greenhouse inside that is) and the heat loss value of the covering materials. A material that insulates well will have a lower heat loss value, which means your required heat output for a heater will be lower. There are plenty of sites on the internet where you can find the heat loss values of regularly used covering materials. Usually you can find a size calculator which can work out your required heat output. This number will normally be shown in BTU/h which is British thermal units per hour, and it is the standardized way to present the heat output.
Fuel Source
Your main options for fuel source are propane, natural gas, paraffin and electricity. You can, if you have the facilities, power an electric heater with solar powered batteries that you have charged, but obviously most people don’t have solar panels. If you are wanting to use natural gas or electricity then your greenhouse has to be equipped for it with plug sockets for example. If you can’t use natural gas or electricity then you’ll be choosing between propane or paraffin. Paraffin was very commonly utilised in the past and was the more popular choice for a while, but now it is a lot harder to get your hands on and therefore paraffin heaters aren’t manufactured as much anymore.
Electric Greenhouse Heaters
Electric greenhouse heaters are a great choice due to their ease of use. They’re simple to set up and run, plus they require very minimal maintenance, if any at all. They tend to be smaller and more portable too, which is convenient for moving or for smaller greenhouses with less space. Additionally, electric greenhouse heaters don’t produce harmful gasses, which is important in an enclosed space like a greenhouse. The main downside of an electric greenhouse heater is that they can be expensive to run, particularly if you are trying to heat a larger space.
Propane Greenhouse Heaters
Propane greenhouse heaters are also a good option for heating your greenhouse since they tend to be portable and budget-friendly. They’re convenient if your greenhouse is not equipped with a power supply from which you could run an electric heater. The primary disadvantage of a propane powered greenhouse heater is that they can produce harmful gasses like carbon monoxide. Most propane heaters will therefore have an automatic shut-off safety system in place, but not all, and it’s not always going to be reliable. You must have proper ventilation and safety precautions in place if you are using a propane heater in an enclosed space.
Natural Gas Greenhouse Heaters
Natural gas greenhouse heaters are more suited to people who are growing larger amounts of crops or plants, perhaps for people who grow their own food or have a business involving growing plants. If you’re a hobbyist then an electric heater or propane greenhouse heater is most likely more suitable for you. Natural gas greenhouse heaters are usually more powerful, allowing them to heat larger areas more efficiently.
They also tend to be much cheaper to run when compared to electric heaters. The problem with natural gas as a power source for your greenhouse heater is that these heaters produce harmful gasses so you must ensure you have proper ventilation in place for your safety. Natural gas heaters are sometimes much more bulky and less portable too. These heaters also are harder to maintain because they need more regular maintenance and also because you need a lot of knowledge in order to do the maintenance. These heaters need fuel refills and regular cleanings.
Solar-Powered Greenhouse Heaters
Solar-power refers to any device that uses the sun’s energy, in this case, uses the sun’s energy to heat the greenhouse. This is great because we have an infinite amount of this energy source so it is sustainable and environmentally friendly since they don’t produce harmful gas. Solar powered heaters are also super low maintenance once they’ve been installed. However, solar powered heaters are only suitable for some places in the world, if you don’t get much sun where you live then your heater won’t run well. Additionally, if you live in an area of the world where the winter has super short days with limited sunlight then you won’t really be able to use your heater over the winter, when you actually need it. Unless you need additional warmth during summer months, solar-powered greenhouse heaters aren’t suitable, which is why there are none on our list of recommended heaters.
Ventilation
Electric heaters also don’t require any extra ventilation to be installed as they do not produce emissions in the way that propane and natural gas heaters do. Some, but not all, propane and natural gas heaters will require really good ventilation. To be safe if you are using propane or natural gasses, it’s always wise to install a carbon-monoxide detector just in case. Most heaters using propane or natural gas burn efficiently, and therefore ventilation isn’t a problem, but some of them don’t and it’s much better safe than sorry as there is a small possibility of carbon monoxide off-gassing.
Static or Forced-Air
Static heaters distribute heat by using convection, this is usually adequate for smaller greenhouses. Sometimes, larger greenhouses, situated in colder climates will need more power than this, in the form of a forced-air heater.
Thermostat
If you want to be able to leave your greenhouse for long periods of time of time, knowing it can sustain and care for itself, then a thermostat is really important, and I would recommend getting a heater with one included. A heater with a built-in thermostat can adjust its heating output in order to only use the energy that is necessary to maintain a stable, set temperature. If you make a lot of visits to your greenhouse then it’s not essential as you can manually measure the temperature and adjust these settings as needed, but it is really useful to have a thermostat.
Safety Features
Safety is of course one of the most important things to consider when buying anything for your home, especially a heater which can pose a fire risk. Keep an eye out for heaters which include safety features like automatic shut-off switches, protection from overheating, fire resistant materials and splash protection or waterproofing.
You may be leaving your greenhouse heater unattended for a long period of time, so it’s crucial that you can feel at ease doing so, and that your greenhouse won’t have burnt down upon your return. Most electric heaters will have a breaker that trips when the device overheats, this will cause it to shut off and stop producing more heat. Some gas heaters will monitor oxygen levels and switch off when they fall low, but it’s important that if your heater doesn’t do this, you get a carbon monoxide alarm. Most heaters, but not all, regardless of power source tend to have an automatic switch off feature for if the unit tips over.
FAQ
What type of heater is best for a greenhouse?
Of course, it’s never a one size fits all situation, but generally most gardeners would prefer a gas heater since they are affordable, efficient and effective. However, it’s important to consider your space and needs first, as well as whether you can arrange for sufficient ventilation.
What is the most efficient way to heat a greenhouse?
Currently, with the technology available, air heaters that use natural gas or propane are the simplest way to heat your greenhouse and are usually cost-effective.
What is the safest heat for a greenhouse?
Generally the best temperature for a greenhouse is between 75ºF and 85ºF during the day in summer, and 60ºF and 76ºF during the night in summer. In the winter months your greenhouse should be around 65ºF to 70ºF during the day and 45ºF during the night. Of course, the safest heat for your greenhouse will depend on what you are growing inside so keep in mind the needs of your individual plants.
Should I put a heater in my greenhouse?
Ultimately, it’s up to you of course! Installing a greenhouse heater is brilliant as it massively extends your growing season, allowing you to produce crops most of the year round. A heated greenhouse also provides an effective way to safely over winter your vulnerable or tender plants, like young saplings and citrus plants.
You Can’t Go Wrong with Big Buddy!
All in all, figuring out the technical jargon and deciding which product is right for you is hard, even if you know all you can and have all the background knowledge there’s still so many choices, so to help you out and make life a little easier we’ve found out top five choices of greenhouse heaters. Big Buddy’s portable propane heater is coming up on top though. It has everything you want in a greenhouse heater, safety features, adjustable heat output settings, a large area coverage and more. Every greenhouse is slightly different and will need different things, but the Big Buddy heater is just such a versatile all-rounder I think I’d recommend it to anyone.
If you’re wanting to increase your yield, expand your growing season but don’t want to spend north of a hundred dollars on the Big Buddy, then get your hands on the Stanley electric heater. It covers a good amount of space, has several heating options and safety features but for only around 20% of the price of the Big Buddy!
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