Greenhouse Heating 101: The Basics

When installing a greenhouse heating system to your greenhouse, you must follow some basic requirements. A greenhouse is as efficient as its heating system; it has to be properly sized to cater to extreme temperatures, and for the sake of your pocket and the planet, carefully planned to avoid heat loss.

Step 1 - Measuring

Knowing the correct length, breadth and height of your greenhouse is fundamental to installing your heating system to assure 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.

Step 2 - Calculating Heat Loss

As mentioned above, heat loss can lead to exorbitant energy bills, depletion of the planet’s resources and unwanted carbon footprints. Heat loss can be calculated by the appropriate formula: A x D x 1.1= BTU’s. Simply explained, A is the sum of the total area of your greenhouse, D is the difference between the coldest night temperature your location can experience, and the required night temperature you want to attain. This formula will give you the required heat or BTU’s. Subtract about 30 to 60 percent if you will be having some form of insulation installed.

Step 3 - Insulation

Heat loss and the units of heat needed will be amplified if you fail to include insulation measures. Insulation can be simple night shades, double glazing, or a polyethylene liner. If your greenhouse shares a heated wall in your house, that also provides insulation.

Double glazing is costly but you can install bubble sheets instead. While they will have to be replaced every few years, they are very efficient in reducing heat loss. Be aware that some types of insulation can cut off light, so install nothing that is permanently fixed.

Step 4 - Sectioning Off

Another efficient way to reduce heat loss is sectioning off areas that house only plants that require high temperatures. Thus you can plan your heating system for that area only, which will greatly reduce your heating requirements.

Step 5 - Choosing the Right System

After all your calculations and planning, you have to choose the right heating system for your greenhouse requirements. Some greenhouses are sold with a heating system included, but if you already have a greenhouse that you have to heat yourself you might consider installing 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 leaving no harmful damp places anywhere.

Another type of heater is the tubular heating unit which emits a soft radiant heat. These units heat the soil not the air and can be wired together to work in a parallel arrangement to produce more heat.

Propane gas heaters are very heat efficient, relatively cheap to buy and install and are suitable for larger greenhouses as they produce more than enough heat.

There is also the type of heater which uses kerosene as fuel. This might be the least expensive heater to run and although it produces a good amount of heat, kerosene is smelly and brings out dampness in the atmosphere which could harm your plants; it also needs frequent and constant cleaning to work efficiently.

Step 6 - Alarm System

If your budget can cover it, you can install an alarm system which warns if the temperature should go down unexpectedly and thus safeguards your plants from sudden cold shock.

As you potter around in your greenhouse and every plant and seed is flourishing, give yourself a pat on the back: you have got your basics right, your heating system is efficient and everything is all right with the world.