Top 10 Best Greenhouse Heaters

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Botanico 2Kw Greenhouse Heater

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  • Compact and lightweight design
  • 2 heat settings controlled by thermostat
  • Frost shield
  • Protects against frost in greenhouses of up to 10 ft by 6 ft
  • Great heat levels for greenhouses of up to 6 ft by 6 ft
Lighthouse 915mm 135W

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  • Uses 25% electricity than other tube heaters
  • Protects growing plants from humidity and temperature changes
  • UK plug included
Sunhouse 40W Tubular

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  • Suitable for floor or wall mounting
  • 1.5 metre long cabling
  • Easy to adjust thermostat
  • Fitted with UK plug
Fireside Small Paraffin Heater

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  • 1.7 litres fuel tank
  • 10 days worth of use approximately on one tank
  • Protects against frost
  • Good quality steel (powder-coated) reservoir protects against rust
Simplicity 2Kw Fan Heater

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  • Suitable for greenhouses as big as 8ft by 12ft or bigger if you only need to protect against frost
  • Adjustable thermostat included
  • Robust Stainless steel heating element

Gardening is a great pastime, and many people find that spending time tending plants is a therapeutic activity. It keeps the mind active, and helps to keep you moving on a regular basis. Plants are a joy to watch unfold; whether you are growing flowers for the garden – or to use indoors – or vegetables, there is plenty of variety and scope for enjoyment. You only need a small space, so even if you have not got a large garden, you can fit a small polytunnel or greenhouse in a corner and tend your plants under cover.

The beauty of a greenhouse is that you get extra heat radiated by the sun’s rays through the glass. This means you can cultivate plants that would not normally thrive in the UK; plants like peppers and other exotics can be brought to grow in greenhouses, along with oranges, grape vines and many other plants can grow very well in a greenhouse – especially if you have additional heating.

Don’t miss: Hydroponic Lights

We’ll talk more about greenhouse heaters in a moment, but we should say that these are not expensive items we are talking about, and they don’t cost a lot to run either. If you are reminiscing about your grandad’s paraffin heater don’t worry – we’re not talking about those in general; we’re talking more modern, sophisticated models, and some that serve a purpose that goes beyond mere heating.

So, for the gardeners among you – and those that may be thinking about getting involved – let’s have a look at some of the best greenhouse heaters available on the market today.

Best Greenhouse Heaters

1: Botanico 2Kw Greenhouse Heater


This is a good model to start with as it is typical of the popular type of electric, portable and very compact greenhouse heaters that are cheap and easy to use. It’s a 2Kw model so quite powerful, and works via a mains power source. The maker’s say it will heat a greenhouse up to 6’x6’ so it’s clearly designed as a small greenhouse heater, and it is very compact and easy to move around.

This one comes with two heat settings that are thermostatically controlled; the heater will keep the greenhouse space at a constant level as chosen by you, whether for heating or otherwise. It also has a frost protection setting; user reviews have stated that this model of heater is effective at protecting against frost in a 6×10’polytunnel, which is exactly what it is made for. Not the most sophisticated heater you will see on the list, and far from the most powerful or versatile, but if you want a simple heater for frost prevention, at this price you really cannot go wrong.

Key Features
  • 2kw
  • Frost feature
  • Up to 6’x6’ heat
  • Electric

2: Lighthouse 915mm 135W


The above model is typical of its design in that it is a floor-standing heater; this we chose as it is typical of another type, the tube heater – akin to a strip light that we would use in the house. It is designed to be mounted on the side or roof of the greenhouse or polytunnel, and is a powerful 135w model that measures 915mm in length. It’s easy to use, surprisingly affordable and will happily heat a good-sized greenhouse.

Like most of these, there is no temperature control; you simply switch it on and it heats to the required level, and switches on and off by thermostatic control for an even heat. It can be set to deal with frost, and is very efficient. This is the more powerful model in the range – there are two others – and is suitable for standard to medium-sized greenhouses and polytunnels, and the makers claim that it is a very efficient model in terms of energy use. For an average size space this one would suffice, but for bigger you may need more than one.

Key Features
  • Tube heater
  • 915mm long
  • 135W
  • Easy to use

3: Sunhouse 40W Tubular

This is another tubular model, in the style of that above, and one that is designed for smaller spaces. It is a 40W model, that’s about as low as you will go for an effective greenhouse heater, and it works from the mains so you need a convenient plug (this can be a problem with these items, so make sure you have a suitable power outlet nearby). 40watts is not going to heat a great area – so this one is perhaps best for very small areas – but what it will do is act as a frost heater at night.

You can set the thermostat at any point on the dial and it will heat constantly to that temperature, and it is cheap to run thanks to low wattage and energy usage. This one is designed to be either mounted on the wall or floor-standing – the fittings are all in the package – and is a neat little heater that does a decent job. Perhaps useful for heating a large cold frame, but if you have a greenhouse of any sensible size you need something other than this.

Key Features
  • 40w
  • Tubular
  • Choice of mountings
  • Thermostat

4: Fireside Small Paraffin Heater

In the introduction we mentioned paraffin heaters as an aside; believe it or not they are still available, and this is one of them. The upside is that a paraffin heater such as this – it has a 3 pint tank – can run for as long as 10 days on one fill. The downside is that paraffin is messy, not as easy to find as it once was, and burning it does cause a smell. Nevertheless, some greenhouse users love paraffin heaters, and this one is designed to be safe, easy to use and effective, and is very cheap.

The major benefit of a heater such as this is that there is no need for electricity. It can be used anywhere, not matter the distance from a power source. It is, however, very small and designed for the smallest greenhouses – 6’x 4’ for example – and cold frames, or perhaps for providing heat in a shed. It will do the job of frost prevention in a smaller space, and if you want a paraffin heater – or have no option but to use this or gas thanks to no available electrics – it’s worth looking at as one of the best parrafin heaters for your greenhouse.

Key Features
  • Paraffin
  • Small
  • 10 days running
  • Frost prevention

5: Simplicity 2Kw Fan Heater

This model is another electrically powered design, and it is rugged, strong and clearly intended for outdoor and garden use. It’s a compact device – it measures just 320x230x198mm – and comes with a neat carry handle on top for ease of movement. It’s easy to use – plug the cable in and you’re away – and it has both a heating element and a fan that can be regulated for temperature.

The heating element is thermostatically controlled so you get even heat – you can choose the temperature on a simple dial – and the fan can be used or otherwise if you wish, by way of a separate selector dial. It’s effective and efficient, and with 2Kw of power is claimed to be able to heat a greenhouse of up to 8’x12’ to a sensible temperature. For frost purposes it will easily deal with a space bigger than that, so is well worth looking at even if it is a little more costly than some.

Key Features
  • Fan heater
  • 2Kw
  • Up to 8×12
  • Electric

6: Sunhouse Tubular 80W

This is another tubular model, in the style of that those already reviewed, and one that is designed for standard to medium-sized greenhouses. It is an 80W model, see a few reviews above for the smaller 40W version of the same design, and it works from the mains so you need a convenient plug (this can be a problem with these items, so make sure you have a suitable power outlet nearby). 80watts is sufficient to heat, say, an 8’x10’ greenhouse to a suitable temperature, and this one will happily keep frost at bay in a polytunnel of such a size of slightly larger.

You can set the thermostat at any point on the dial and it will heat constantly to that temperature, and it is cheap to run thanks to low wattage and energy usage. This one is designed to be either mounted on the wall or floor-standing – the fittings are all in the package – and is a neat little heater that does a decent job. This one comes recommended for anyone who wants a sensible size of heater that is not expensive to run and buy, to heat or keep frost at bay in a normal sized greenhouse.

Key Features
  • Tubular
  • 80W
  • All mounting
  • Thermostat

7: Apollo Single Paraffin Heater

We must admit that, when we began researching for these reviews, we were not expecting to see such a choice of paraffin heaters still available. However, on second thoughts it makes sense; many people, for example, have greenhouses on allotments, which may not be party to an electricity supply, or in larger gardens a long way from power. In these situations, the option is for a heater with its own energy source – which limits you to paraffin or to gas, with little other options.

This is a standard type of paraffin heater that you may have seen in greenhouses in the past, but it has been brought up to date in terms of safety standards. It’s perfectly safe for use in greenhouses, has a 4.5litre capacity and will burn for 7-days continuously, and will easily heat a small to standard size of greenhouse or shed effectively. The usual downsides are getting hold of the paraffin, and the smell, but this is a quality model made to a high standard, so worth a look.

Key Features
  • Paraffin
  • 4.5ltr
  • 7-day burn
  • Safety features

8: Parasene Superwarm 4

We’re sticking with paraffin for this entry, too, as we feel we need to cater for people who don’t have an electricity supply close to their greenhouse or polytunnel. This one is another modern update of the old-fashioned type of paraffin heater – for the record, we don’t recommend you using an older one as they can be very dangerous – and is safe and easy to use. It’s a very compact design, so one that is not intended for use in larger spaces.

Indeed, the maker reckons that this will be useful for heating a 6’x6’ greenhouse; that’s not going to be sufficient for most of our readers – we reckon 6’x8’ is about the minimum you will be using if you are into your gardening – but it should be good for a large cold-frame. It will also be useful for frost prevention in a standard size of greenhouse. If a small paraffin heater is what you need, perhaps for your potting shed, then this is worth looking at.

Key Features
  • Paraffin
  • Safety features
  • Easy to use

9: Biogreen Phoenix Electric Heater

So far we’ve looked at a selection of very cheap, usable heaters of various designs, that are intended primarily for smaller spaces. This model is a fan heater of a different ilk; it has three power settings – covering 1.0 to 2.8kw – and is designed to heat up to 100ft². That means your 8’x12’ greenhouse – a large one for a standard garden – will easily be heated by this one. Also, if you want frost protection, it can handle an even bigger space than that – up to 180ft², and we can’t see many garden greenhouses covering that area.

This one is electric, it’s a small tubular heater that is floor mounted – it also comes with chains that mean it can be hung from the roof if needed, which leaves more floor space for plants – and it is easy to use. It comes with various settings – it can also be used in cool mode for ventilation – and it is designed with a very quiet fan. All in all, it’s a very good greenhouse heater that should service any garden installation – including conservatories – but be aware it is considerably more expensive than the rest on this list.

Key Features
  • Very powerful
  • Up to 8×12’
  • Three settings
  • Can hang

10: Dimplex Ecot 1ft 40W

While the model reviewed just above is designed for larger spaces, this one is clearly intended for the smallest possible installations. It is a tubular heater, measuring just one foot in length, and has a heat output of 40watts. Clearly, that’s not going to heat even your 6’x8’ greenhouse, although it will provide adequate frost protection for such a size, and perhaps for one slightly larger.

This heater is intended for very small greenhouses and polytunnels, and perhaps larger cold frames. It could also be used if you are growing plants indoors – on a windowsill perhaps – and need some extra heat at times. It has a thermostat so will heat to a constant level, is easy to use and comes with a lengthy cord, and is very cheap, so if you have a limited space needing extra heat, have a look at it. For the record, it’s also available in some larger sizes, so check out the range for more options.

Key Features
  • 40W
  • Only for smaller spaces
  • Tubular design

That’s our selection of the top 10 greenhouse heaters – some of which will be sufficient for you, others which may be lacking – so is there one here that will do the job? Before we talk about the verdict, let’s remind ourselves of some of the key features.

Important Features

If you are in the market for a greenhouse heater there are certain factors that you will be taking into account. Let’s have a recap:

  • Electric or Paraffin – if your greenhouse is close to the house, or near a convenient power socket, then the electric heaters on the list will do the job. If not – perhaps yours is tucked away down the garden or in an allotment with no power – then you should look at the paraffin heaters we have listed.
  • Power – this goes hand in hand with the size of the greenhouse you want to heat; most garden greenhouses will be around 8’x8’ to 8’x12’ – the latter being large – and not all of the above heaters will manage that space, so you need to check with the manufacturer specifications to ensure that the heater you choose will do the job.
  • Type - with electric heaters, the type of heater is important; do you want one that is floor standing, or would you prefer that it could be mounted on the side or above? This is a choice with most of these. Also, you may want to differentiate between the tubular and fan-type heaters.

So, that’s our selection of the factors to look for when searching for the best greenhouse heater, which of the above is for you? Let’s see if we can come to a verdict.

How It Works

Like heaters that you use in the house, greenhouse heaters come in a variety of forms, and also offer various different levels of power. This gives you great choice when you want to buy one, but also means that you need to know what you are looking for. The standard size of greenhouse found in UK gardens and yards is around 6x8ft; that’s a decent space in which to cultivate plants of many kinds, and doesn’t take much heating. Many of the heaters on our list will do the job, so you should be able to find one if you have a greenhouse of around this size.

For bigger spaces, you can of course find more powerful heaters – or use more than one – but there is another purpose for which heaters are used in greenhouses and, we should say, also in conservatories. One of the biggest problems with plants in the UK is that of frost; it can strike even in the summer – on clear nights especially – when the temperature drops, and it can be a major problem for the more sensitive plants.

Many of the heaters we have featured have a frost function; it’s designed to keep the space heated to a sensible night-time temperature, and to keep the frost at bay. This is a very useful function, as it means the plants get the correct difference between daylight and night time temperature without the risk of damage from frost.

A greenhouse heater is a sensible option if you want to make sure your plants have the best environment to grow in – and especially if you are thinking of growing from seed – so let’s take a look at the top 10 greenhouse heaters on the market right now, and see if we can help you find the one for you.

Let’s Wrap It Up!

So, you want the best greenhouse heater, and you don’t know which to buy. Let us help you choose!

First, if you don’t have available electricity, you need a paraffin heater, and the best of the bunch here is clearly the Apollo model, which will heat a small greenhouse with ease. It will also provide more than adequate frost protection.

If electric is good for you and you prefer the tubular style, then there are several to choose from, yet we recommend you look at the Sunhouse range, as it comes in various different power levels.

For a floor standing heater, and indeed as the pick of the bunch, we can’t get away from the Biogreen model, at number nine. It’s powerful, efficient and will heat a bigger greenhouse, and although it is more expensive than the rest, we feel the sheer ability will be worth the money.

So, get your heater on and give those seedlings a better chance, and enjoy your gardening to the full.

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