Do you need a greenhouse heater?
Gardening has become the hobby of choice in this chaotic and stressful world in which we live. It is relaxing, rewarding and something where you can involve family members of all ages.
- 1 Do you need a greenhouse heater?
- 2 5 Minute Overview
- 3 Best Pick Greenhouse Heater – In Brief
- 4 Why trust us?
- 5 What is a greenhouse heater?
- 6 Who needs a greenhouse heater?
- 7 How we picked our greenhouse heaters?
- 8 Any other considerations?
- 9 Our Best Pick Greenhouse Heater
- 10 Our Best Budget Greenhouse Heater
- 11 The Best of the Rest
- 12 Frequently Asked Questions
- 13 Summary of Greenhouse Heaters
Unfortunately, we live in the UK and the weather isn’t too kind to us here. We experience high winds, lots of rain and of course freezing temperatures throughout the winter months. In order to continue to grow herbs, vegetables and other green fingered delights throughout these cold spells most of us have invested in or built a greenhouse.
Gardeners using greenhouses have a couple of common problems:
- Low temperature during winter
- Wind and water ingress
We can look at various insulation methods, we have prepared a guide on how to greenhouse insulation methods. But fundamentally the best way to keep your plants at the temperature they need throughout the winter months is greenhouse heaters.
In this guide we will go into some theory about greenhouse heaters, who needs one and suggest some of our favourites. We try to look at our overall favourite best pick (2kW Greenhouse Fan Heater) and one that is great if you are on a budget. We also show you some of the competition for you to have a browse through.
5 Minute Overview
The idea of this section is if you only have 5 minutes to spare, what do you need to know about Greenhouse Heaters in brief and what are our best budget and best pick greenhouse heaters?
If you are looking to protect your plants from the often harsh weather in the UK, keeping them in a greenhouse is a sterling idea. To regulate the temperature correctly a greenhouse heater really is a must.
Main advantages of a greenhouse heater
- Temperature regulation, keeping optimum temperatures for growing crops and plants.
- Allows for gardening all year round.
- Allows for heating and ventilation in your greenhouse.
Key considerations of a greenhouse heater
- Look for one with an IPX4 splash proof rating.
- Look for one that has an automatic thermostat to regulate temperature.
- We prefer electric as the power source for a greenhouse heater (more information below).
We have provided all of the background research on greenhouse heaters below, but if you need to know the high points, that should get you started. Below we have our best pick greenhouse heater and a best budget greenhouse heater.
Our Best Pick
Our Best Budget
Best Pick Greenhouse Heater – In Brief
Our best pick is the 2kW Greenhouse Fan Heater The price point that this model comes in at is very reasonable when you consider it comes with a digital thermostat as well! This is a 2kW model that is capable of circulating 186m3 per hour. We look more in detail at this greenhouse heater further down this article. We did also consider the Bio Green PAL greenhouse heater for the review, but the price is almost three times that of the one we chose, weighing up its features and specification we didn’t think it made the cut.
Why trust us?
The internet is full of review sites that claim they have bought and rigorously tested every product so they can give you the best buying advice, Tripadvisor has some fake reviews, who do you trust?
Let us be straight from the off, we provide the following, we get a product category or subject area, find out everything you could possibly want to know about it, find some of the best products for sale in the category and combine it all into a concise buyers guide.
If we were buying something that is exactly what we are looking for, we don’t care much for someone’s opinion, we want facts, the best products based on specification and reviews and it all
What is a greenhouse heater?
Plants need a few key elements to grow and develop;
- Water and nutrients – plants take the water and nutrients from the soil to help them grow and develop.
- Fresh air and clean soil – too many pollutants can harm your plants growth, this is why although we have covered electric greenhouse heaters in this review, if you consider paraffin greenhouse heaters you need to consider ventilation.
- Light and temperature – This is why we have greenhouses that are primarily windows, plants need light. An inherent problem with lots of windows though in the winter months is they create a cold space, that is where our greenhouse heaters add so much value.
Greenhouse heaters allow us to regulate the temperature in our greenhouses, it is important to ensure that the temperature equally isn’t too hot. Our best pick 2kW Greenhouse Fan Heater and our budget option Sunhouse SHTTH2 both have thermostats allowing for temperature regulation.
Who needs a greenhouse heater?
If you live in the UK and have a greenhouse, the chances are you are the person who needs this product!
There are several things that need to be considered, firstly if you have built or purchased a greenhouse purely to offer shelter from the cold winds and a basic level of frost protection, then perhaps a greenhouse heater isn’t for you. But if you are serious about gardening I feel it is probably a must.
There are things that you can do to help the heater, such as insulating your greenhouse, reducing how hard your greenhouse heater has to work and also your energy bills.
How we picked our greenhouse heaters?
When we set out on our journey to bring you an article that was comprehensive in nature, providing you with the key takeaways you needed to decide on the best greenhouse heater, we built a list. We looked at:
- Feedback rating – we wanted a feedback rating of at least ⅘ stars.
- It needed to have an automatic thermostat built in, ideally digital.
- IPX4 splash rating – safety first and it’s likely to get wet when watering plants.
- Not a deal breaker but ideally a metal casing.
- As you will see below, we weighed up electric, paraffin and propane as sources of power, we decided on electric.
We took these key deciding factors and applied a bit of a test case to them, we wanted something capable of heating adequately an average size greenhouse (around 8’ x 10’). For this we were looking for something with a power rating of around 2kW. Whilst some have smaller greenhouses and some much larger, we felt this would be most representative of our readers.
As we explain in our “Why Trust Us” section, we haven’t had hands-on with these greenhouse heaters. Instead we have put in hours of research to give you somewhere to come to find out everything you need to know about buying, owning and running a greenhouse heater. We have selected our best pick and best budget based on the criteria above, we feel this will help most of our audience. We then mention some of the competition, although this didn’t quite make either of our choices they are still worth a mention or considering for your particular case.
Any other considerations?
What things do you need to be aware of if you are thinking of buying a greenhouse heater. There are several fueling options to consider paraffin, propane and electric. I would also think it relevant to consider insulating your greenhouse before embarking on your journey.
Paraffin Greenhouse Heaters
Paraffin prevents a whole host of issues as a fuel for a greenhouse heater, including;
- Not cheap to purchase
- Flammable so storage is a consideration
- Produces moisture, so greenhouse needs good ventilation
- Produces harmful fumes
Another thing to be aware of with paraffin or other gas powered greenhouse heaters is the fact that they require topping up. Whereas an electric greenhouse heater can run continuously and self regulate through using a thermostat.
Propane Greenhouse Heaters
One of the benefits to non-electric greenhouse heaters, be it paraffin or propane powered is that it doesn’t matter where your greenhouse is located and there is no need for mains electric. Sometimes a mains supply isn’t feasible.
Propane is a much cheaper fuel than paraffin and is readily available at supermarkets, petrol stations and local DIY shops.
Propane greenhouse heaters come with the same inherent problems as paraffin greenhouse heaters, in that there is the danger of a flammable gas and a burning flame that could prove hazardous in a greenhouse. Again it would require you to ensure your greenhouse is well ventilated which will in turn lead to it being cold and requiring more heat.
For me the biggest reason to avoid propane as a source of fuel for your greenhouse heater is that it causes even more moisture in the greenhouse than a paraffin heater. We have already seen that moisture leads to mould, this isn’t healthy for our plants or us.
Electric Greenhouse Heaters
So, why have we based the crux of this article on electric greenhouse heaters? If you choose the correct one, they are the most energy efficient of the three, provide the most control when it comes to automation of temperature control and are the safest of the three greenhouse heaters.
Let us then dig a little deeper into each of these areas. Firstly, cost, whilst I appreciate the cost of electricity is only heading one way, with a well insulated greenhouse, learn how to insulate your greenhouse here you can heat yours on a fairly tight budget. The negative to the gas powered greenhouse heaters is a lack of automated temperature control, this means either you keep going and taking temperature readings and manually turning the heater on and off or you leave it running constantly. Either way this leads to large running costs and not a great climate for growing your plants in.
The electric greenhouse heaters we have selected for our best pick and best budget option both come with automatic thermostats on them. Not all electric greenhouse heaters come with automatic thermostats, but most do. These are great, you can research the optimum growing temperatures for your plants, set it and forget it, the heater will automatically startup and shut off to keep the temperature in your greenhouse consistent.
Of course having a gas bottle and naked flame in any environment is dangerous, whilst being in a greenhouse it isn’t likely to get knocked or disturbed. Aside from the structure of the greenhouse there is likely little that could catch fire, it still makes me a little uneasy the thought of gas and flames. Electric greenhouse heaters are therefor in my eyes a much more safe offering.
But, what if you don’t have mains electricity in your greenhouse or indeed outside at all? What are your options? You could consider solar power, however due to the nature of running a heater being quite a thirsty electric device this may not suffice. You could also get an outdoor extension lead. These will run from a socket in your house or garage and into your greenhouse, they have cable suitable for outside and IP rated sockets on the other end to stop issues with moisture or liquid. Whilst this isn’t a permanent solution it does the job just fine through the winter months should you wish.
Your other option is running a cable from a socket at the back of your house underground to your greenhouse to provide a socket and power inside your greenhouse. This sounds complex and possibly even overkill, we have written a guide to show you just how simple wiring an external socket is.
Reducing Heating Costs
Another consideration regardless of whether you opt for an electric greenhouse heater, a paraffin greenhouse heater or a propane greenhouse heater is how can we reduce your heating costs.
There is a lot that can be done by way of insulating your greenhouse properly, we have written an article on the subject looking at all ways you can insulate your greenhouse, even though it is largely made of glass or perspex and can be fairly flimsy in nature.
There is also the consideration of when you come to choose a greenhouse heater choosing one that consumes less power or is energy efficient.
Our Best Pick Greenhouse Heater
- Measurements: 230x198x320
- 2kW Fan only: 25W IPX4 rated
- a 2kW will heat up to an 8x12 greenhouse, possibly a little bigger if you only want it frost free.
- If you are pushing the borderline with this, then take extra measures during a very cold snap (e.g -10 at night) such as adding more heat or turning the thermostat up to allow a bigger buffer during the coldest part of the night.
So after performing research into everything surrounding greenhouse heaters and what makes a good greenhouse heater, we looked at what was available on the market. If you have an unlimited budget you could throw money at the problem you may just choose the dearest. But we wanted to strike a balance of a heater that is perfectly capable of heating an average sized greenhouse, that ticked all of the boxes laid out in our “How We Picked” section and didn’t break the bank.
We finally settled on the 2kW Greenhouse Fan Heater, this unit has a small footprint and so doesn’t take up much space at all. It is something that can be placed on a table or on the floor thanks to its IPX4 splash proof rating and contains a 2kW fan.
This unit manages to circulate 186m3 per hour of air around the greenhouse, in an average sized greenhouse of around 8ft x 12ft this should be perfectly adequate to keep the temperature just right. We have seen more expensive models such as the Bio Green PAL that only actually delivers 163m3 per hour.
It comes with a seperate thermostat that once you set the temperature will automatically turn your greenhouse heater on and off as required to maintain the set temperature.
When setting up your greenhouse heater it gives you the option to choose 1KW or 2KW mode, obviously the former is more energy and cost efficient but depending on the outside temperatures and time of year that might not suffice. There is also the option to use the greenhouse heater in fan only mode, ideal in the summer months to keep the airflow circulating in your greenhouse without the requirement for heat.
Our Best Budget Greenhouse Heater
- 80W tubular heater Includng wall mounting brackets
- Built In thermostat
- Approx 2ft in Length (713mm total length)
- Designed for continuous operation
- Splashproof to IPX4 Standard
Our best budget greenhouse heater goes to the Sunhouse SHTTH2 whilst this isn’t going to heat the greenhouse to the same temperatures as our best pick, it is still something worth considering.
In my eyes this is more suited if you have a smaller greenhouse or you are looking for frost protection, even on its lowest setting it has a frost protection mode to keep your plants safe. It does also feature an automatic thermostat so that once your greenhouse gets to the required temperature it will automatically turn off.
Depending on where you are situated in the UK can also have a bearing on whether or not this is a viable solution, if you live in Scotland or the Lake District where you get extreme temperatures it may not be the model for you.
One big plus for this unit is its energy efficiency, it is very cheap to run and would be a model that maybe a contender for solar power. We have discussed that some maybe in a situation where they don’t have outdoor power as a source for their greenhouse heater. With its lower power consumption, a well positioned solar panel could be just the ticket.
The Best of the Rest
Not a fan of our best pick or best budget buy greenhouse heaters? Or maybe you just want to be aware of the competition out there. Below we have listed a selection of other alternatives, we have included some electric and some gas powered greenhouse heaters.
- Garden & Outdoors
The Bio Green greenhouse heater packs a punch, whilst being one of the most expensive models in our review. Its air circulation is slightly less than our best pick at 163m3 per hour but it’s heat output is huge, at 2000W. It’s thermostat ranges from -50C – +99C. This really is a high end greenhouse heater, but in most cases may be a little overkill.
- 40 % longer burning time
- Energy saving
- Promotes healthy growth
- Easy to use
- Traditional design
Another product from the Bio Green stable, this time a paraffin variant. This is a smaller greenhouse heater than the rest and is only really suitable for greenhouses up to 10’ x 6’. Once the fuel tank is full of paraffin you are looking at a run time of around 110 hours with both burners lit, so about four and a half days. We have discussed the positives and negatives of paraffin greenhouse heaters above.
- Select from 3 heating options at: 1kW, 1,8 kW, 2,8 kW, with an adjustable thermostat from 0 - 26° for more control over the heat. Not only does it act as a fan heater but cooler also, keeping you well wentilated!
- Safety Feature: The heater will automatically switch off temporarily should it overheat. To restart, switch off the device for 5-10 minutes to allow for cooldown. Blockages in the air inlet or exhaust apertures may also cause automatic shut-off. In such cases check the air intake vent is not blocked or obstructed.
- Very quiet smooth running fan | On/Off Indicator Light | Comes with hanging chains and floor mounting brackets included!
- Stainless steel drum, black heat resistant plastic. Warning: Hot to the touch when powered on!
- IP44 Rated - Water resistant design. Length - 37.5cm | Width: 22cm | Height 30cm (inc. floor brackets) | 3 pin standard UK plug (lead length approx 130cm)
Whilst this greenhouse heater is capable of heating small greenhouses right up to greenhouses of around 10’ x 20’, it is possibly a little overkill for the average greenhouse. This unit has three different heat settings, 1000w, 1800w and 2800w. It is also useful as a fan in the summer months to provide
Frequently Asked Questions
In the main yes, an electric greenhouse heater even more so. But as with anything safety precautions need to be taken. If you are using gas powered heaters, I would recommend a carbon monoxide detector in your greenhouse, as the excess gasses that can be given off can be deadly.
It depends on what you deem as expensive. It is also dependent on your electricity tariff but as a rule of thumb you are likely to be looking at around £4 per day to run a standard electric greenhouse heater.
Depending on the size of your greenhouse and I am talking more about what would be considered a desktop sized greenhouse, something you would see more propped against a wall in a garden with a few vegetables in, yes. You can get the same sorts of bulbs you would use in a vivarium to heat a cold blooded animal and that would suffice.
If you want to go natural and not use a greenhouse heater, there are several options. You can use black wood mulch for any walkways you have, insulate your glass with plastic or add heat absorbing barrels.
Unfortunately, in the UK, yes. Whilst there maybe some heat in the sun, thanks to the glass windows, it isn’t enough to keep your plants at the required temperature.
An ideal temperature for your greenhouse is around 26 degrees. This is the optimum temperature for your plants to grow to their full potential.
Whilst some vegetables are pretty hardy and Winter-proof such as shallots, garlic and spring onions, others are much better growing in your greenhouse. Examples of these would be, Winter salads, carrots and pak choi.
Summary of Greenhouse Heaters
In summary, as you can see growing and cultivating plants in a greenhouse is a pretty involved subject. A greenhouse heater goes a long way in helping you achieve the results you are looking for. Hopefully in our buyers guide you have managed to collect enough nuggets of information to help you decide the best greenhouse heater for your budget and situation.
If you have any feedback on our buyers guides or would like to see a guide on a particular group of products please get in touch, we love feedback and helping our readers is our primary goal.
Greenhouse Heater - Buyers Guide
Last update on 2019-03-25 / Affiliate links / Images from Amazon Product Advertising API