Are Paraffin Heaters Safe to Use?

*In layman terms, paraffin and kerosene are considered the same with a few subtle differences, for example, kerosene has a stronger odor as compared to paraffin. However, their heat properties and mode of heating are the same. In this article, we have considered paraffin and kerosene to be the same as the answer to this question is the same for both types of fuel.

The main benefit of a greenhouse heater is that it can be used to heat up the greenhouse in the wintery cold conditions when the sun outside may not be as bright as you would want it to be.

As the greenhouse doesn’t receive enough heat from the sun and can also lose some heat, it becomes quite necessary to use a heater in the greenhouse in cold conditions.

Are paraffin heaters safe

There are various types of heaters available and one of the more popular types of heaters is the paraffin or kerosene (as it is more popularly called) heater. They can provide excellent heating and will not cost a fortune to run.

But are paraffin heaters safe to use in a greenhouse?

Paraffin or kerosene heaters are generally quite safe to use in a greenhouse. They are being used extensively. However, like any other heater that uses fuel to burn, there are some safety aspects you must consider before using them.

Safety Considerations while using Paraffin Heaters

The best option while using a paraffin or kerosene heater is to have ample ventilation in the greenhouse. Most of the modern, portable kerosene heaters that you get in the market today are unvented paraffin heaters. They are built for maximum efficiency and are less likely to have incomplete combustion.

Nevertheless, there will be some water vapor and in some cases, gases like carbon monoxide and sulfur dioxide, if the efficiency of the heater has gone down. These gases along with water vapor can be harmful to the plants. Hence, it is advisable to use an unvented paraffin heater if there is sufficient ventilation in the greenhouse.

You also have the vented heaters but they burn roughly and do not have as much efficiency as an unvented heater.

Are kerosene heaters safe

Ensure that you use only 1-K grade kerosene in your heater. If you use other grades of kerosene, it is more likely to release a higher quantity of pollutant gases in the air. Even though you may have some ventilation in the greenhouse, an increased level of pollutants may harm the plants.

Using other forms of combustible fuels inside a paraffin heater can increase the risk of an explosion. Always keep in mind that as mentioned above, you must only use K-1 kerosene and not mix it with any other fuel.

Ensure that the paraffin heater is well-maintained and is devoid of rust. If you’re using the traditional paraffin heater, keep the wick clean so that it burns efficiently. You may also want to keep the flame shorter, to prevent the accumulation of soot and risk of incomplete combustion, which releases harmful gases.

Do not refill the portable heater inside the greenhouse especially near the plants or any fabric. When the heater has cooled off, take it outside in open air and then carefully refill it without filling it up to the brim.

Choosing a Safe Paraffin Greenhouse Heater

Although those were some steps you can take to ensure that your paraffin greenhouse heater runs safely, the first step in ensuring heater safety is buying a safe and suitable heater.

First and foremost, you must know that paraffin heaters are usually of two types: The convection type and the radiant type. While radiant heat heaters are good for heating a specific area or surface, convection heaters are used for the overall heating of a big room or in our case, a greenhouse. Hence, you need to opt for a convection type paraffin heater for your greenhouse.

Next, ideally, you should use a vented heater in a greenhouse. Especially with paraffin or kerosene, a vented heater helps the exhaust gases and the odor to escape. So if there is any leakage of toxic gases like Sulfur Dioxide or Carbon Monoxide, they can escape through the vent attached to the heater.

However, vented heaters are not very efficient and can be a bit cumbersome to set up considering you have to set up a ventilation system and attach the heater. Alternatively, you can use a non-vented heater which is highly efficient and portable as well. It comes with a wick whose height can be adjusted. The kerosene is vaporized with an electric heating mechanism which then burns with a blue flame to heat the space.

Here’s a non-vented kerosene/paraffin heater, which is efficient and highly-rated, with an output of 23000 BTU which is ideal for a small home greenhouse. And here’s another example.

Non-Vented Kerosene/Paraffin Heater

For a non-vented paraffin heater, it is essential to ensure that there is provision for the combustion gases to escape and fresh air to circulate inside the greenhouse. This can be done by providing adequate ventilation in the greenhouse. You also need to maintain and clean the heater at regular intervals.

There have been some technological advances in the design of non-vented paraffin heaters. Some of them now use an electrically-operated fan which forces the hot air out. These heaters are wick-less and have an electronic or laser ignition system. They are highly efficient and are much-more environment-friendly. Considering the high emphasis on safety and automation, they are available at a higher price. Here’s an example of one such type of paraffin/kerosene heater.

Some other factors to consider while choosing a paraffin heater

We’ve already been through the different safety factors you need to consider while choosing a paraffin heater. Now let’s see some other factors you need to consider while buying a paraffin heater.

BTU rating

BTU stands for British Thermal Unit which is the non-SI unit of heat that is widely used to indicate the heat output of a heating device. The kerosene heater that you need will depend upon the area of the room or greenhouse you want to heat and the heat output of the heater.

Different heaters have different BTU output. An average non-vented paraffin greenhouse heater has a heat output of around 15000 BTUs/hour. So while heating a typical small greenhouse, you would need more than one heater.

Duration of Combustion

The duration of combustion of a heater will depend on the fuel tank capacity and the heat setting of the heater. If the fuel tank is large, the paraffin heater will keep burning for a longer duration. Ideally, if you want to keep the heater burning overnight, you need a larger fuel tank which ensures uninterrupted heating during the colder months.

If the heater has a thermostat for setting the heating level, the high or low heat setting will determine for how long the heater will keep running. If it is set at a low temperature, the heater will keep running for a longer duration and vice-versa.


While ideally, a vented heater is preferred for heating a greenhouse, for greater efficiency and ease of use, a non-vented paraffin heater makes more sense as it is more portable. It can be carried outside and refilled as it is considered safer.

Also, in case of repair or replacement, it is easier to carry the heater outside for as needed.

Even though there are some safety considerations while choosing a paraffin heater for heating the greenhouse, if they are well adhered to, a paraffin heater is just as safe as any other heater.

5 thoughts on “Are Paraffin Heaters Safe to Use?”


    • Hi,

      If you’re looking for a traditional paraffin heater with a wick, you should try this heater, which also has a variant that uses a double burner for more enhanced burning. Another option is to use this Japanese heater which is an intelligent, electronic paraffin heater that is much more economical and odorless as well as it does not use a wick. (Please note, the Japanese heater requires an electric mains supply to operate the fans and for the ignition)

  2. Interesting article, thank you.
    I would like to know how best to ventilate a greenhouse without losing most of the heat generated by the paraffin heater. Leave the door ajar? Leave the window open slightly? What would you recommend?

    Many thanks.

    • Hey Mike, thanks for reading! I would suggest you keep the windows slightly open so that there is just enough ventilation without losing the heating effect.

  3. Hi can you tell me the stuff your putting in to make it less smelly thanks


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