Twin Fans

12 products

Twin fans have two fans in one insulated casing, set up as run and standby, so ventilation carries on if one motor stops. They are used where extract must not fail, such as commercial toilets, plant rooms and other critical supply or extract systems. We stock the Systemair KVK Duo with AC motors from 125mm to 315mm, the KVK Duo EC from 150mm to 630mm, and the KV DUO 315 EC, all in fully insulated AluZinc casings suitable for outdoor and roof installation. Use the buttons below to filter, or for help choosing, email hello@efans.co.uk or call 0161 399 3825.

Frequently asked questions

What is a twin fan?

A twin fan, also called a run and standby fan, has two fan and motor sets in one casing. One fan runs while the other stands by. If the duty fan fails, the standby fan takes over, so the system keeps running while the failed motor is repaired.

How does the changeover work?

The changeover between the two fans is handled by a run and standby controller or by the building controls, which also allow the fans to be alternated so both share the running hours. Check the datasheet for the model you are looking at, or ask us and we will advise on the controls.

AC or EC twin fan?

The AC KVK Duo models are the lower cost option. The EC models use less energy, run quieter at reduced speed and are speed controlled through a 0-10V signal. Use the buttons above the products to filter by motor.

Single phase or three phase?

The KVK Duo AC models, the KVK Duo EC models up to 400mm and the KV DUO 315 EC run on a single phase 230V supply. The KVK Duo 500 EC and 630 EC are three phase.

Can twin fans be installed outside?

Yes. The KVK Duo and KV DUO have fully insulated AluZinc casings and are suitable for outdoor and roof installation as standard. They can be installed in any position.

What air can a twin fan handle?

Clean or contaminated air at temperatures up to 60°C. They are not suitable for greasy kitchen extract or hot process air: see our high temperature fans for those.

AC EC Single Phase Three Phase