Your plants have spread beyond the small light you started with. You're ready to upgrade, but now there are four much bigger options in front of you. Would 800W be enough, or is it worth making room for a longer light? And what will the extra power add to your electricity bill?
For a roughly square growing area, I'd start by comparing the OC720 720W LED Grow Light with the OC800 800W LED Grow Light. If your plants run along a long bench, the OC1200 1200W LED Grow Light and OC1600 1600W LED Grow Light are the more relevant shapes to look at.
This guide compares these four lights by size, output, running cost and how they fit above your plants. By the end, you'll be able to narrow your choices by space and budget, and judge whether extra power is worth paying for.
Which light would I look at first?
Start with how your pots or trays are arranged. That narrows the four options into two pairs.
- For a roughly square layout: look at the OC800 800W LED Grow Light first if you're considering more output in a similar frame size. It measures about 1.12m on each side. The OC720 720W LED Grow Light is the lower-power alternative, with a slightly smaller frame and a built-in driver. Check availability before planning an order around it.
- For a long growing bench: start with the OC1200 1200W LED Grow Light. Its 1.8m frame follows a long row of plants more naturally than a square fixture. That makes it worth comparing for the layout; a light-distribution map will help you judge how well it lights the whole bench.
- For a larger installation: consider the OC1600 1600W LED Grow Light when you have room for its 2.1m frame and a reason to use the higher output. It also brings a bigger electricity allowance, so the extra capacity should have a job to do from the start.
If you're lighting a few pots on a windowsill or a shallow shelf, a smaller panel or shelf light will usually be easier to accommodate. Turning a large fixture down can reduce its output, but you'll still have the same frame hanging above you.
What do you get for the extra power?
The table below keeps the main differences together. PPF is the total plant-useful photon output; efficacy tells you how much of that output the light produces per unit of electrical energy. These figures come from the product listings, rather than our own comparative test.
| Light | Frame size | Listed PPF | Listed efficacy | Main difference |
|---|---|---|---|---|
| OC720 720W LED Grow Light | 105 × 108.5 × 4.2 cm | 1,872 µmol/s | 2.6 µmol/J | Roughly square, with a built-in driver |
| OC800 800W LED Grow Light | 111.5 × 111 × 9.3 cm | 2,320 µmol/s | 2.9 µmol/J | Eight-bar folding frame; Samsung LM301B LEDs |
| OC1200 1200W LED Grow Light | 180 × 111 × 6.8 cm | 3,120 µmol/s | 2.6 µmol/J | Longer twelve-bar folding frame |
| OC1600 1600W LED Grow Light | 210 × 111 × 6.8 cm | 4,640 µmol/s | 2.9 µmol/J | Sixteen bars in a 2.1m frame |
The step from 720W to 800W is fairly modest in physical size. You gain higher listed output and efficacy while adding 80W of power. That's the pair I'd compare when the current layout is staying roughly square and you don't want a much longer fixture.
The move from 1200W to 1600W is a bigger decision. The frame gets 30cm longer and power rises by 400W. A higher total output can be useful, but you'll want to know where that light lands before paying for it.
This is where a PPFD map helps. It shows readings across the growing surface, so you can see the middle and edges together. Compare maps at the same height, dimming setting and area. A bright centre is less helpful if the pots around the outside receive much less light. Reflective tent walls can also change the readings, so compare similar surroundings.
How much more electricity would you use?
Multiply power in kilowatts by the hours used, then by your electricity rate. For example, 800W is 0.8kW; running it for ten hours uses 8kWh at that power.
Here is the same calculation for all four options. It assumes full listed power, ten hours a day, thirty days and R3 per kWh. Those are comparison assumptions, not a current South African tariff, measured consumption or a lighting schedule for your plants.
| Power | Energy over 30 days | Cost at the example rate |
|---|---|---|
| 720W | 216kWh | R648 |
| 800W | 240kWh | R720 |
| 1200W | 360kWh | R1,080 |
| 1600W | 480kWh | R1,440 |
In this example, the first step costs another R72 a month. The jump from 800W to 1600W adds R720. That's a useful difference to keep beside the purchase price, especially if you're planning to use the light for a long time.
Replace the example rate and hours with your own. Fans, other equipment and fixed electricity charges sit outside this calculation. If you dim the light, measured input power gives you a better estimate than assuming a 50% dial setting always means half the watts.
Will it be easy to hang and work around?
Before ordering, imagine watering the back row or lifting a tray out. A light that looks right on a product page can still be awkward in a crowded space. A few measurements now can save you rearranging everything later.
- Measure the plants and the hanging space separately. Mark the area occupied by pots, then check the space available above them. The fixture's dimensions tell you whether it fits, not how much plant area it lights effectively.
- Leave room above the frame. Hanging hardware, leads and the clearances in the installation instructions all need space. The thickness listed in the table is only the light itself.
- Keep your usual route clear. Make sure you can reach the back pots and move a tray without working around a low bar. Include your fan and its position when sketching the layout.
- Check the controls in the box. The OC1600 1600W LED Grow Light listing shows the external dimmer and dimming cable as optional. Include them in the order if your setup needs them, rather than assuming every pictured accessory is supplied.
If you're replacing an existing light, take a photo of its label and hanging points alongside your measurements. Keep the new quotation and package list too. Similar names can refer to different LEDs or control arrangements, and those details make it easier to check what you've ordered.
Conclusion
For a roughly square layout, begin with the smaller pair and compare whether the 800W option's extra output is useful. For a long bench, look at the 1.8m option before moving up to the larger 2.1m frame. Compare all four in the LED grow-light range, with your measurements and monthly running budget beside you.
FAQs
These are a few questions that often come up once you've narrowed the choice down.
How many watts should an LED grow light be?
Start with the area occupied by your plants, what you're growing and how much daylight they already receive. Then look at the fixture's light-distribution map. A wattage figure tells you the electrical power, but it can't choose the right light for every room or plant count.
How can I compare the coverage of two grow lights?
Put their PPFD maps side by side using the same height, area and output setting. Look at the edges as well as the centre, and check whether reflective walls were used. That gives you a more useful comparison than the highest number on either map.
Are bar lights always better than quantum boards?
No. A broad bar light may fit one layout well, while a compact board is easier to hang in another. Compare the specific fixtures for size, light distribution and everyday access. The shape alone doesn't make one the better purchase.
Does wattage tell me how hot a light will feel?
Only part of the story. Surface temperature also depends on the cooling design, airflow and room conditions. LED lights still produce heat, so a frame that feels relatively cool doesn't mean you can forget about ventilation in an enclosed space.