Gardening is a year-round hobby and passion that can be enjoyed in any weather, especially if you have a heated greenhouse.
Greenhouses help keep delicate plants and brand new buds safe from winter weather, but sometimes even a greenhouse needs a helping hand. Glass can only do so much when the temperature drops.
If you live somewhere like the United Kingdom, for the most part, you may just need a little heater to keep away the frost or help you stay comfortable when you are pruning and sorting.
If you have a larger greenhouse or live somewhere a little colder, cold frosty nights could be a killer for your plants, and you may have to invest in a larger electric greenhouse heater to help get you through the winter.
What’s the right greenhouse heater for me?
You’ll have to consider multiple factors, and we take a look at each one when we look at all the different types of heaters:
- Square footage: Is the greenhouse heater powerful enough to heat the space? Always look at the square footage the garden heater can heat, especially when considering gas VS Electric greenhouse heaters.
- Power source: Do you have an electric plug nearby? No? A Propane or Paraffin Greenhouse heater may be for you.
- Cost of running: The cost will be a factor depending on how long you plan on using it. Do you need it for the occasional frost, or will it stay on for days? If the latter, it may be worth investing in solar greenhouse heaters.
- Safety and Thermostats: Check whatever you buy is safe for the space, and if you can, make sure you buy a Thermostatic greenhouse heater that will automatically turn on or off as needed.
We take a look at the different garden heaters for greenhouses and whether they are suitable for your needs.
Electric Greenhouse Heaters
These are the most versatile, but they require an electric plug. These are not always easy to find in a garden, especially if your greenhouse is far away from the main home.
If you are lucky enough to have electricity running to your glasshouse, then you are in luck. You have a lot of options available for all sizes and needs.
Home Away From Home: Electric Oil-filled radiators
If your greenhouse is closer to a conservatory, or you plan to spend a lot of time there, an oil-filled radiator is for you.
Electric radiators are expensive to run, especially if you plan on having them on all of the time. But that’s why we recommend oil-filled greenhouse radiators as a more economical alternative.
The oil warms up faster and stays warmer for longer, even once you’ve reached optimum temperature, giving you more value for money.
- Warms rooms of up to 26m2
- Multiple heat settings with a built-in thermostat allow you to pick the perfect temperature for your plants or you
- Built-in safety feature which makes it automatically turn off when it tips over
- A 24-hour timer allows you to choose when the heater will turn on or off. This will improve energy efficiency and lower your energy bills in the long run.
- 2500W, 1300W and 1200W
- Portable if you need to use it elsewhere
- At the higher wattage, this will turn a small greenhouse into a tropical paradise. Do you need this high heat? Especially as the higher the wattage the more electricity it consumes and the higher your running costs.
- More expensive to buy than many of the electric garden heating options. A bigger first-time investment, but it will last you for years and it’s a flexible option.
The all-rounder Greenhouse Heating: Electric fan heater
These are the most popular electric greenhouse heaters online. Mostly because they do two things well: they come in various sizes, and the fan distributes the heat quickly and effectively around your greenhouse.
What it’s not great at doing is keeping the heat. Once it’s off, it’s off, and your glasshouse will turn cold almost instantly. But, to keep away frost or to bring with you to keep you warm when working outside, these are great options.
- Low wattage means they are cheap to run
- Can heat up to 20m2
- Thermostats help keep your greenhouse at a steady 7C or 42F degrees without you having to do fiddle with knobs, buttons, or wiring.
- Safety features avoid overheating
- 3 different fan and heat settings make it easy to use
- Great as year-round frost guard
- Only greenhouse heater with digital thermostat
- They’re not pretty. These are functional machines that will sense when it gets too cold and blast just enough hot air to keep your plants comfortable.
- They will not keep a human warm, you’ll need some extra layers when you head to your glasshouse to keep an eye on your plants.
- Keep away from condensation. They are not waterproof, so keep away from any automatic sprinklers or tuck it away when you go in to water the plants.
Eco-Friendly Greenhouse Heating: Electric Tube Heaters
If you’ve glanced down at our greenhouse solar heater and your eyes popped at the cost, come back here and find the best environmentally friendly heater alternatives.
We conclusively worked out that electric patio heaters are more eco-friendly than gas, but they can be more expensive to run and more difficult to plug into the mains.
If you want the complete package, and have that all-important plug – cheap to run, keeps the frost away, and eco-friendly, electric tube heaters are for you.
- Built-in thermostats to regulate the room temperature
- Water resistance and manufactured in high-quality seamless tube – perfect for wet environments like a greenhouse.
- A cost-effective way to heat your room as wattage is low but the output is even.
- Perfect for preventing condensation, freezing, and damp
- These compact heaters use less electricity than fan heaters and are cleaner than paraffin heaters
- Horizontal and vertical mounting. Or you can simply leave it on the floor and move it around as you need it.
- Overheat safety cut out
- A relatively cheap option to keep the frost away.
- These are perfect for low-level background heating. They will not heat your greenhouse for tropical plants or for human comfort. Think a max amount of 10C or 52F degrees.
- Better for smaller greenhouse spaces of 10m2. If a bigger space, invest in an electric fan heater or buy multiples.
Gas Greenhouse Heaters
There is only one type of safe gas greenhouse heater, Paraffin heaters. And that’s fine. We are not all lucky enough to be close to an electricity source.
Propane greenhouse heaters are not safe for glasshouses, conservatories, or indoor spaces.
Propane requires a well-ventilated area, and if you are going to use something like it, it’s really only to use when you have the door open and you are inside; keeping an eye out on the propane patio heater.
Paraffin greenhouse heaters
The good news is that Paraffin heaters are a great alternative and (if used correctly) burn smoke-free. It’s probably one of the most economical glasshouse heaters because Paraffin is cheap, and one tank can run for days.
What it’s not is high tech – rarely will you find a thermostat. You just have to trust that the constant heat will keep the frost away or test it by standing in your greenhouse and seeing if it takes the edge off.
You’ll want to keep it away from direct contact with your plants because these have flames, but they burn with a clear blue flame that is smoke and gas-free.
Ultimately these are great for amateur gardeners with small glasshouses where temperatures outside rarely go below -6C or 20F. They are easy to use, set up, and quick to warm up.
- Can last for 40 to 80 hours depending on the number of burners
- Attacked straight to a Paraffin can as and when you need it.
- Easy to set up and plugin
- Paraffin is cheap to buy and replace
- Burn smokeless and gasless
- Safe for indoor use
- It will generally only warm a small glasshouse of up to 5m2. If you get a Twin burner you can get a higher heat, but you’ll need to replace the paraffin tank quicker (think every 40 hours).
- No thermostat or timer – you have to manually turn it on at night and then turn it off in the morning
When talking about gas garden heaters, you are usually looking at either propane or paraffin, but there’s also Kerosene which (unlike propane) can be used in indoor spaces.
Why are we just mentioning it? Because it’s not a good long-term solution. Kerosene greenhouse heaters don’t technically exist, but you can get plenty of camping heaters running off Kerosene which you can buy and use.
But not only can Kerosene be more expensive than Paraffin, but it burns at a higher heat, making it better as a heater than a frost guard.
In other words, if you want a gas heater to keep the chill away while you garden, in combination with a frost guard glasshouse heater, this is a good solution. If you want to leave it overnight, you’ll get maybe one night out of it if you are lucky.
- Can heat up to 20 meters square
- Easy to hang up in the middle of a glasshouse for maximum heat coverage
- The maximum heat generation is 9000 BTU/H (equivalent to 3000W), which is more powerful than if using the greenhouse heaters’ electric.
- Smokeless, tasteless, and safe for indoor use
- Can also be used as an outdoor camping stove
- A 6L. tank will give you a fuel time of 18/24 hours. This isn’t a long time if you are looking to cover multiple days in a row and will require back-up tanks if you have a long frost ahead.
- Not as economical as the Parrafin heaters.
Solar greenhouse heaters
What’s the cheapest greenhouse heater to run? Solar greenhouse heaters, of course. Why? Because solar energy costs you nothing.
But unfortunately, while solar heaters are the cheapest to run, they are not the cheapest to buy. A heater needs a lot of power, far more than any solar-powered lights to border your plants.
However, if you want to be eco-friendly, you don’t have a plug to get an electric heater, and you don’t mind splashing out on a device that will (in the long run) pay for itself, then these are great options.
Portable Power Station with Solar Panels
Currently, no solar greenhouse heater is powerful enough to get a glasshouse warm enough to keep the frost at bay. What you can get is a power station that collects solar rays and turns them into energy.
This power station has multiple output outlets, so you can use it to charge your phone, plug in your stereo, or pretty much anything that uses electricity.
See where we are going here? You get yourself a solar power station and one of the best electric greenhouse heaters for your space, and you are sorted. Or maybe you have a rechargeable greenhouse heater but want a more energy-efficient way to charge the battery.
Either way, this multi-use power station has a million uses beyond the greenhouse, and it’s as clean energy as you can get.
- You can use it to charge up anything electric – including an electric glasshouse heater.
- You can buy additional solar panels for a quicker charge
- You can plug it straight into the mains to charge if cloud cover is making things difficult
- One 120W solar panel can quickly charge the power station in 5-6 hours
- Noise-free, zero emissions, completely eco-friendly
- The most economical way to run a greenhouse heater – literally no cost
- Easy to use and carry for any electrical needs
- 500wh of portable power on the go and supports devices up to 300W
- Solar panels fold into a compact carry case
- EXPENSIVE. It’s expensive to buy. There’s no upside, no way around it, these cost a lot of money upfront.
- Won’t work for a high output oil base radiator, but will provide ample electricity for any of the other electric heaters, and certainly will charge up several phones and laptops.
What’s the best overall glasshouse heater?
Look, we wish there were only one choice. It would make this list much easier to write.
Ultimately, if you have access to an electrical plug, we recommend you use one of the electric greenhouse heaters.
- They provide the widest range of heat output
- They are the cheapest to run
- Thermostat gives you the most eco-friendly way to ensure you don’t use more heat than you need
If you don’t have a plug, you are left with gas heaters, which are cheap to buy and cheap to run, but you need to do more hard work to ensure the gas doesn’t run out. But they are best for smaller spaces.
And, of course, if you want to go all out, and invest in a neat little gadget that will help you lower all your electrical costs (including charging the kids’ iPad), then a solar-powered power station is a great investment.
We hope you find the perfect glasshouse heater for you and keep your fingers green and warm.