The real value of greenhouse heating

Is Greenhouse Heating an Extra Cost or a Smart Investment?

Many growers in Southern Africa feel that heating their greenhouse is unnecessary. Our winters are mild, and energy costs are high. The common logic is “why add another expense?”

But the growers who do invest in heating are pulling ahead. They’re producing steadier yields and better quality produce. This means they’re supplying markets for longer periods, and securing better prices. 

Heating isn’t just about warmth. It’s about creating and controlling your climate and your yield.

So the real question isn’t “should you heat?”. It’s “how do you do it smartly?”

The Challenge (and Payoff) of Heating a Greenhouse

Heating is one of the most complex systems in any greenhouse. You can’t just add heaters and call it done. Without proper design, energy is wasted and costs spiral. But with the right plan, heating can be a foundation for stability, scalability and consistent crop performance.

South Africa’s reliance on coal has kept heating affordable in the past. That’s changing. As coal has become more unreliable, energy costs soar, making heating not only expensive, but uncertain. At the same time, market demands are rising: buyers expect consistent quality, tighter specifications and supply that extends beyond natural seasons - making heating or climate control a must. 

We see the difference on the ground with our clients. Growers without heating are bound to the seasons. Those with heating have a business that runs all year. But how do they balance the cost of heating, whether CAPEX or OPEX, with the opportunity cost of not heating?

Before we think of solutions to this conundrum, let’s look at what heating actually entails.

Understanding Greenhouse Heating Systems

Every greenhouse heating system is built on five key elements. Together, they decide how warm your greenhouse stays and how efficiently your money is used.

1. Heat Generation

At the centre of the heating ecosystem is a boiler, basically a giant geyser that heats water. Fuels to power the boiler can be coal, diesel, gas or oil. And renewable energies like biomass and solar are starting to enter the mix too. The right fuel choice for your greenhouse depends on local costs, availability, and your long-term sustainability goals.

2. Heat Distribution

Insulated pipes carry hot water from the boiler room into the greenhouse. A central system can feed multiple compartments, but only if it’s designed to minimise heat loss and handle future expansion.

3. Heat Transfer

• Underfloor heating warms the root zone through concrete, gravel, or soil.
• Pipe-rail systems run along the floor like train tracks, spreading heat and doubling as rails for trolleys.
• Radiators and fin pipes push heat into the air.
• Air heaters use fans and coils to make quick temperature changes.

The right mix of heating equipment depends on your crop, layout and workflow.

4. Heat Storage

Large insulated tanks store hot water, usually at around 90 °C. They act as a reserve, keeping the greenhouse at a stable temperature through cold nights or if the boiler goes offline. 

5. Heating Control

Monitoring and automation systems, like Priva's, keep everything in balance. Sensors read the internal temperature and automatically adjust valves and pumps to keep conditions stable. Think of it as a smart shower mixer, blending hot and cold water to keep every zone at the right temperature. These systems help to cut energy waste and remove the need for manual adjustment and constant human oversight.  

The Business Case for Greenhouse Heating

Breaking down the mechanics shows why heating is never one-size-fits-all. Every decision – fuel source, piping layout, transfer method, storage and control – affects crop health and operating costs.

When done right, heating gives you:

• Consistency
• Stable climate reduces stress and improves uniformity.
• Longer seasons
• Produce crops earlier and keep harvesting later.
• Pricing power
• A steady supply secures better markets.
• Resilience
• Smart storage and controls protect against outages and waste.

When done poorly, heating can eat up cash. Weak insulation, undersized boilers, or badly designed zoning can turn heating into a drain instead of an advantage.

There’s also the difference between CAPEX and OPEX costs. Higher CAPEX costs like solar installations make the OPEX cost of heating almost negligible, whereas relying on coal involves lower CAPEX costs, higher OPEX costs and the risk of unreliability. 

Right now, coal might look like the cheapest route. But relying on it is risky. Policy changes, market pressure, and sustainability commitments are reshaping the energy landscape in a way that may make coal unreliable in the long term.

Heating is becoming one of the most important tools in modern greenhouse farming. Whether powered by conventional fuels or new energy sources, it can play a big role in yield, consistency, and quality. The key is to design systems that balance cost, efficiency, and sustainability, so growers can stay productive no matter what the energy landscape looks like next.  

Let’s Heat

There’s no universal heating formula.

The best system is built for your crops, your climate, your resources, and your long-term growth plan.

We’d love to be the ones who help you get there. Reach out to us on +27 21 987 6980 or info@vegtech.co.za