Since modern flats have less space for ventilation, an exhaust fan is usually a necessity. Switch on the exhaust fan in your kitchen or bathroom and it will suck out all the smoke, bad smell, fine dust particles and stale air. Many models of domestic exhaust fans, also called fresh air fans, are available in the market. Consumer Education and Research Society (CERS), Ahmedabad, tested 13 models of domestic exhaust fans for safety, air delivery, service value, energy consumption and sound level.
The 12-inch domestic exhaust fans with metal blades tested were Almonard Fresh Air Fan, Bajaj Bahar, Crompton Drift Air Plus, Elpar Fresh Air Fan, Havells Ventil Air DS, Khaitan Euro Freshair Fan, Orient Airflow, Usha Turbo Nova, Shaan (high speed) and Zigma (high speed). Three other models with plastic blades that were tested were Bajaj Maxima DX, Orient Spring Air and Almonard Zoom Freshair Fan.
The Bureau of Indian Standards (BIS) does not specify any standards for domestic exhaust fans. Therefore, none of the models tested carried the ISI mark. CERS tested the exhaust fans for power leakage, insulation resistance, earthing continuity, electrical input and protection against direct current. All of them were found to conform to the safety requirements for commercial or industrial purpose ventilating fans set by the BIS.
Usually, exhaust fans are fitted with an external guard (grill or mesh). Such guards are useful to prevent accidental contact with moving parts of the fan. Orient Spring Air and Almonard Zoom were not provided with such guards.
Air delivery is the volume of stale air pushed out by an exhaust fan. Among the fresh air fans with metal blades and normal speed, Usha Turbo Nova had the maximum air delivery (1652m³/hr) and Elpar Fresh Air the minimum (1125m³/hr). The air delivery of Shaan and Zigma, both high speed fans with metal blades, was (1797m³/hr) and (1567 m³/hr), respectively; however, their energy cost was the maximum and their sound levels were also high. In the plastic blade category, air delivery of Bajaj Maxima DX was the most (1401m³/hr) and Almonard Zoom the least (1252 m³/hr).
Service value is the efficiency of a fan. The higher the service value the better the air delivery and lower the energy cost. Among the fresh air fans with metal blades and normal speed, service value was maximum for Orient Airflow (32.37) and minimum for Almonard Fresh Air (18.17). The service values of two high-speed metal blade fans Shaan and Zigma were 19.96 and 17.11, respectively. In the plastic blade variety, the service value of Bajaj Maximum DX was the highest (27.13) and that of Almonard Zoom the lowest (17.68). Overall, Orient Airflow had the highest service value (32.37) and Zigma (high speed) the lowest (17.11).
Overall, Orient Airflow consumed the minimum electrical energy; Zigma (high speed) consumed the maximum. Both models are of the metal blade variety. The two “high speed” metal blade exhaust fans Zigma and Shaan consumed the maximum energy. The energy cost of Zigma was more than double that of Orient Airflow.
With a sound level of 60.9 decibel, Bajaj Maxima DX was the least noisy exhaust fan among all the models tested. Shaan (high speed) was the noisiest (74.3 decibel).
Ease of use
Only Bajaj (Maxima DX and Bahar), Crompton Drift Air Plus, Usha Turbo Nova and Orient (Airflow and Spring Air) models provided installation and maintenance instructions in their manuals. Except Shaan, Zigma and Almonard (Fresh Air and Zoom), none of the models were provided with a plug. Power cords of Crompton Drift Air Plus, Bajaj (Maxima DX and Bahar), Khaitan Euro Freshair and Usha Turbo Nova were of better quality than the other models.
The maximum retail price (MRP) was not marked on Shaan and Zigma, which is a violation of the Weights and Measures Act, 2011. The price of Zigma was the lowest (purchase price was Rs 540); Bajaj Maxima DX, which had plastic blades, was the most expensive at Rs 1,290.
Selecting the right exhaust
For a typical Indian kitchen, a fan with metal blades is the best option because you can clean it easily. A 12-inch exhaust fan is suitable for a kitchen that is 10x9x8 cubic feet. For bathrooms and toilets, exhaust fans with plastic blades are the best option because such blades do not rust. A complete plastic body fan, preferably with louvers, is ideal. The louvers stop insects, birds and dust from entering the bathroom.
The tests revealed that though all the 13 models tested conformed to the safety tests, their air delivery and electricity consumption differed widely, and hence, their service value also varied. Consumers should make a conscious decision depending on their need. For small spaces, an exhaust fan with high service value would be best because such a fan will give you sufficient air delivery with low energy cost. But for bigger spaces perhaps you wouldn’t like to compromise with the air delivery of the fan, even if it adds a little more to your energy bill.
Based on overall score, Orient Airflow and Usha Turbo Nova are the best buys in the metal blade variety. In the plastic blade category, Bajaj Maxima DX is the best buy.
CERS suggests that consumers avoid purchasing Shaan and Zigma as their energy consumption, utilisation cost and sound levels were high. Also overall construction of the two models was poor, which may affect their durability and safety in the long run.