EC and AC fans: how to compare energy costs?

What is the savings calculator for?

The calculator helps estimate electricity savings over a year. It compares two ebm-papst fans with a diameter of 63 cm, one with an EC motor (model: S3G630-DQ37-35) and the other with an AC motor (model: S6E630-DN01-35), controlled by the ELETOR SC-S controller. For the calculator to work correctly, enter two items from your own electricity bill: the price per kWh and the transmission charge rate. Then specify the ventilation level as a percentage — from 0 to 100%.

AC vs EC 630

Savings:

When is it worth buying ebm-papst fans with electronically commutated motors (EC for short)?

The ventilation of a livestock building and its efficiency depend mainly on the fans used. The price of the fan itself is not the final cost. Costs incurred during use must also be added, such as wear and depreciation, as well as electricity costs. Wear and tear is a natural part of using any equipment. Fans run almost continuously throughout the year, under varying loads and changing climatic conditions. Continuous operation is, however, covered by the manufacturer's two-year warranty. ebm-papst fans are, of course, designed to operate for much longer than the warranty period. Even so, depreciation is not the most important fixed cost when buying new equipment. During the warranty period, the investor can be confident that the fan will operate without problems. Electricity is a much more significant cost. By knowing their individual electricity rates and the estimated average operating level of the fans, investors can therefore estimate how much they will save on electricity over a year by choosing an EC fan instead of an AC fan. The savings can then be compared with the price difference between AC and EC fans. If two years' electricity savings cover the difference in the price of the fans, the investment is worthwhile. After the two-year warranty period, every month of trouble-free operation will represent a net saving for the investor. The calculator is pre-set with the rates from our own electricity bill. To estimate savings accurately, each investor must use the rates from their own electricity bill. However, our calculation shows that the difference in the purchase price of the fans will be recovered within the warranty period.

When is it worth buying ebm-papst fans with asynchronous motors (AC for short)?

To be honest, we have found few such cases. Global leaders in industrial fan manufacturing are already moving away from producing asynchronous motors. Ebm-papst specialises in fans with EC motors, seeing them as the future of ventilation thanks to their low power consumption, durability, performance and quiet operation. There are, however, situations where it is worth considering a fan with a conventional AC motor. These are the very arguments that convinced ebm-papst to design AC fans for the agricultural sector.

1. Low price.
2. Quick replacement during servicing.
3. Long payback period at extreme fan operating levels.

Ad. 1 . Low price

Fans with AC motors cost almost three times less than EC fans.

Ad. 2 . Quick replacement during servicing

Most investments in livestock buildings in Poland are based on fans with asynchronous motors. If ventilation needs to be brought back into operation quickly, a damaged fan can be replaced at a low cost. The supports for chimney fans (both AC and EC) fit the mounts used for fans from other brands. If they are not compatible, our mounting brackets can be purchased separately; their design allows flexible installation in the chimney.

Ad. 3 . Long payback period at extreme fan operating levels

Our calculator simulation clearly shows that at extreme fan operating levels — that is, when running at very low or maximum speeds — savings decrease and the payback period extends beyond the two-year warranty period. This involves a certain element of risk. If the fan were to fail after the warranty period, the cost of repair or replacement with a new unit could exceed the benefits of the earlier savings.

How to compare energy costs yourself

The archived form used a script from the previous page. A comparison can be made using actual power consumption, operating time and energy cost. Savings should not be calculated solely from the fan diameter or the controller's percentage setting.

Energy consumption [kWh] = power [kW] × operating time [h]. To calculate the cost, multiply consumption by the price per kWh. For varying operating conditions, calculate each period separately and add the results together. The difference in cost between the AC and EC options is the basis for comparison.

The calculation requires data for both devices under comparable operating conditions. This post is archival material, not a current offer or a promise of a specific saving.