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EC Fans... Why The Hot Air?

EC Fans... Why The Hot Air?

Posted by Adam on 29th Jun 2023

As technology advances and energy prices keep rising, it's inevitable that growers are starting to look for ways to improve the overall efficiency of their grows. As we saw with the HPS to LED revolution, we're now witnessing a similar movement from AC fans to EC fans. If you're wondering what all the hot air is about, keep reading below and we'll break things down for you!

What's the main difference between AC and EC fans?

When it comes to powering a fan motor, there are two main electrical delivery methods available: AC and DC. In simple terms, AC motors use a more basic technology that draws directly from the AC plug power source, while DC (EC fan) motors use an inbuilt transformer to convert AC to DC. For AC motors, speed is regulated by a resistor that is relatively unstable and inefficient. For DC fans, the power delivered to the motor is directly regulated by an EC (electronically commuted) controller, making the whole process much more efficient.

So which is better?

Based on what we've said so far, you'd be correct in thinking that DC motors are generally superior to AC. The delivery of power to the motor via DC is much more effective and efficient than with AC and the irregular forces applied to AC motors accelerate wear on the parts over time, while causing a buzz/hum (that's energy that could be used for rotational force being lost to sound). Furthermore, AC motors will continue to draw maximum power regardless of how fast they're spinning, while the power that DC motors use will be directly proportional to the speed selected - meaning that genuine energy savings can be had by reducing fan speed where possible.

What size should I get?

As a rough guide, for grow areas 1m squared and under, a 4" EC fan will handily take care of all but the most energy intense set-ups. If you've got a 1.2m x 1.2m tent, we'd recommend using a 6" EC fan. 1.5m x 1.5m tents should use at least 8". When it comes to getting the most out of any EC fan in your space, it's always better to oversize the fan and run at a lower speed setting. The advantage of this is that you'll see an improved lifespan and experience quieter operation, while also giving yourself extra power for when you need it - for example during a heatwave or if you decide to upsize your grow space.

Which brand of EC fan is best?

Here at Green Spirit, we only stock quality fans from reputable brands. Which brand suits you best will come down to your own list of requirements and priorities.

If you want your fan with a speed controller that can regulate speed based on either temperature or humidity parameters, there are plenty of options out there. The Whispair Silenced EC extraction fans are an ideal option, each fan comes with a manual dimmer inside the box and also provided are multiple adaptors to be able to connect to most popular controllers including the GAS controllers

Are EC Fans Quieter than AC Fans?

While it's true that EC fans are significantly quieter than AC equivalents, we need to keep these claims in perspective when considering a purchase based on reducing noise levels. Most of the unnecessary noise generated by AC fans comes from the buzz/hum associated with the inefficient transformer, so the advantage from EC fans is greater at lower speeds. When it comes to full speed operation, much of the noise generated by both AC and EC duct fans will come from the exhaust turbulence. As mentioned previously, if minimising noise is a top priority you're always better off getting the largest fan possible and operating at a slower speed. However, in order to deal with the noise from airflow, you'll need to actively dampen this turbulence. This is where silenced fans come into their own.

With a layer of acoustic foam built into the fan's housing, the noise generated by air flow is significantly lower with 'silent' acoustic fans like The Whispair Silenced EC extraction fans . The EC motor and acoustic foam combination drastically minimises any noises coming from your extraction with some of the higher end silenced EC fans such as the systemair Revolution vector EC fan taking the quality of the acoustic foam to the next level, achieving genuinely remarkable levels of soundproofing.


With EC motors now taking over from older AC technology, we don't think it'll be long before they become the new standard for fan motors everywhere. If efficiency, noise, power and adaptability are top priorities for you when purchasing an extraction fan, then you really can't beat EC technology.

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