How to Efficiently Heat a Greenhouse

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When installing a heating system to your greenhouse, you must follow some basic requirements. Keep in mind that a greenhouse is only as efficient as its heating system—after all, providing a warm environment to your plants is the whole purpose of a greenhouse! When planning an efficient greenhouse heating system, everything has to be properly sized to cater to extreme temperatures and, for the sake of your pocketbook and the planet, carefully planned to avoid heat loss. Here's some basic steps to take to when it comes to creating an effective heating system for your greenhouse.

Get Accurate Dimensions of the Greenhouse Itself

Knowing the correct length, width, and height of your greenhouse is fundamental to installing the proper heating system to ensure that it will always provide the correct temperature without over- or under-heating. This is necessary to provide your plants with the correct environment to support growth. Make sure you go through the process of measuring the greenhouse more than once to get accurate numbers.

Install Insulation to Keep the Heat from Escaping the Greenhouse

An insulated greenhouse.

Your greenhouse's heat loss will be amplified if you fail to include insulation measures in the structure. Insulation is available in a variety of forms and can be as simple as night shades or a polyethylene liner, or a more complex double glazing of the glass. While double glazing is efficient, it is a more costly option. For a more budget-friendly alternative, you can install bubble sheets instead. While they will have to be replaced every few years, bubble sheets are very efficient in reducing heat loss. (If your greenhouse shares a heated wall in your house, that will also provide insulation.) Be aware that some types of insulation can cut off light, so install nothing that is permanently fixed.

Choose the Right Greenhouse Heating System

Once you have accurate calculations, you have to choose the right heating system for your greenhouse requirements. Some greenhouses are sold with a heating system included, but if you have a greenhouse that requires a separate heating system, there are several options. The first are electric-powered fan heaters, which are easy to use and won’t cause pollution. These fan heaters blow hot air evenly and continuously around the greenhouse without leaving harmful damp spots within the structure. Another greenhouse heating option is a tubular heating unit that emits a soft, radiant heat. Instead of heating the air within the greenhouse, these units heat the soil and can be wired together to work in a parallel arrangement to produce more heat.

    A third option for a greenhouse heating source are propane gas heaters, which are very heat-efficient, relatively cheap to buy and install, and suitable for larger greenhouses as they produce more than enough heat. An even cheaper option uses kerosene as fuel. While a kerosene heater is the least expensive to run and produces a good amount of heat, kerosene has a distinct odor and causes atmospheric dampness, which could harm your plants. Kerosene heaters also need frequent and constant cleaning to work efficiently.

      Isolate Plants that Require High Temperatures

      A thermometer in a greenhouse.

      Another efficient way to reduce heat loss in your greenhouse is to section off within the structure areas housing plants that specifically require high temperatures. You can then plan your heating system for that area of the greenhouse only, which will greatly reduce your heating requirements overall and keep your plants as healthy as possible in their own separate ecosystems.

      Install an Alarm System in the Greenhouse that's Sensitive to Temperature

      If your budget can cover it, you can also install an alarm system which will warn you if the temperature within the greenhouse should decrease unexpectedly. This alerts you to take action in regulating the termperature of the greenhouse, as well as safeguards your plants from sudden cold shock.