Ventilation Fan with Home Assistant

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Username1

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#324313 26-Mar-2026 23:09

Does anyone know of any ventilation fans that can easily have speed controlled locally in home assistant? I can't seem to find much online. The best I could find was an AC Infinity fan that can apparently be speed controlled with a Shelly Dimmer 10v. Does anyone have any suggestions for brand or something that isn't too difficult to setup?

Tinkerisk

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#3474203 27-Mar-2026 06:08

I am using a Xiaomi Smart Tower Fan 2 directly controlled by Home Assistant via WiFi.

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everettpsycho

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#3474268 27-Mar-2026 09:09

When you say ventilation fan do you mean like an extractor fan in the bathroom?

If it's like ours when you go up in the attic they are just plugged in to a cable, you could probably use any old smart plug to turn them on and off. I've toyed with it and then putting in a sensor so they will just turn on when the humidity creeps up.

HowickDota

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#3474271 27-Mar-2026 09:30

The shelly dimmer should work with any ec fan that has 0-10V speed input.

Typically the fan comes with a speed selector (potentiometer) that has connects to the fans internal 10v as input and 0v as reference and varies output between 0v (dc ground) and 10v.

You would disconnect the fans speed selector wires (10V will be unused) and connect the 0V wire to the shelly's 0V and the 0-10V input wire to the shelly's 0-10V output, typically they fan has black for 0v and yellow for 0-10v input but best to check with a multimeter.

The shelly's power supply will connect to 230V line and neutral.

Username1

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#3474272 27-Mar-2026 09:32

Sorry I should have given more information, my house came with a Sayr Ventilation system and I hate it. If I turn it off at the controller it turns itself back on after some time and it is very loud on maximum speed so I am consistently having to adjust the temperature on the controller to get it to slow down. I really want a fan that I can automate and control the speed of so it isn't loud.

timmmay

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#3474273 27-Mar-2026 09:51

I got a decent ventilation fan, had it set to a medium speed, and control it with a WiFi plug. No speed settings, no screen, just on / off. Works great. I have a TPLink Kasa WiFi switch, it's been in the hot ceiling cavity for years with no issues.

Username1

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#3475450 30-Mar-2026 11:52

HowickDota:

The shelly dimmer should work with any ec fan that has 0-10V speed input.

Typically the fan comes with a speed selector (potentiometer) that has connects to the fans internal 10v as input and 0v as reference and varies output between 0v (dc ground) and 10v.

You would disconnect the fans speed selector wires (10V will be unused) and connect the 0V wire to the shelly's 0V and the 0-10V input wire to the shelly's 0-10V output, typically they fan has black for 0v and yellow for 0-10v input but best to check with a multimeter.

The shelly's power supply will connect to 230V line and neutral.

Thank you, that is really helpful and doesn't sound to hard. I might give that a go first and if I fail that I'll try timmmay's idea.

How powerful of a fan would I need for ventilation? Would something like this be good enough?

https://herbals.co.nz/products/cloudline-pro-s8-quiet-inline-duct-fan-system-with-speed-controller-8-inch

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nzben

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#3475456 30-Mar-2026 12:08

Why don't you just use the AC Infinity + controller. Sure it's not home assistant or whatever, but it is app based, can be accessed from anywhere once it is Wifi connected and once you set a temp/humidity based schedule it's set and forget. I have a system setup for home ventilation and I just let it do its own thing, the only adjustment I make is summer going into winter and then back into summer.

You can also restrict the max and min speed that the fans work, which I do to limit noise and probably prolong the lifespan.

Username1

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#3476361 31-Mar-2026 23:18

I did think about that but I would prefer something controlled by home assistant as it is so much easier not having to deal with so many different systems.

What kind of cheap filter box would you guys recommend? And is it better to draw air from the roof space or outside?

timmmay

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#3476447 1-Apr-2026 10:32

I got this filter box with filters from AliExpress after a lot of research. It has a pre-filter, charcoal filter, and HEPA filter. I draw air from outside as my roof space is old and smelly, it will just bung up the filter faster.

tweake

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#3476736 1-Apr-2026 16:43

a lot of the ecm fans i've seen use 0-10 volt for speed control, which is common in industry.

outdoor air is best, but ceiling air can have some benefit. easy enough to put the motorised damper in to switch from outdoor to ceiling.

Username1

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#3488060 6-May-2026 12:57

Thanks HowickDota, the colours all matched your description. Now I can control the AC Infinity S8 from home assistant and the Shelly fits into the enclosure which makes things really simple.

Thanks timmmay I'll have a look at that filter.

tweake:

a lot of the ecm fans i've seen use 0-10 volt for speed control, which is common in industry.

outdoor air is best, but ceiling air can have some benefit. easy enough to put the motorised damper in to switch from outdoor to ceiling.

Ok thanks, would a motorised damper from AliExpress work fine? I see they come in 12v and 24v, which one should I get? Also how am best to control it? I see some people on the Internet saying an ESP32 relay board.

When would I use outside vs ceiling air?

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Mattnzl

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#3488079 6-May-2026 14:19

@username1

If you go into the SAYR filter reset menu (touch the SAYR word on the screen then settings button 3 times) there are a few extra options like Max fan speed.

I set my Max to 50% and Min to 5% to quieten it down. There is also a fan/temp gain setting which adjusts how much the fan speed increases based on the temp spread between roof/house so you can make it so there needs to be larger differential in temps before it goes ballistic.

tweake

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#3488186 6-May-2026 17:27

tweake:

a lot of the ecm fans i've seen use 0-10 volt for speed control, which is common in industry.

outdoor air is best, but ceiling air can have some benefit. easy enough to put the motorised damper in to switch from outdoor to ceiling.

Ok thanks, would a motorised damper from AliExpress work fine? I see they come in 12v and 24v, which one should I get? Also how am best to control it? I see some people on the Internet saying an ESP32 relay board.

When would I use outside vs ceiling air?

not sure about 12v. typically its 24vac or 240vac.

the simple way i did it is to use 24vac power supply. i use a simix 5856 diagram installed in the ceiling. set to your desired room temp. when ceiling temp goes higher than room damper opens to allow outside air. this also helps keeps keep the ventilation from shutting off from high ceiling temps.

Username1

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#3488939 8-May-2026 20:13

Mattnzl:

@username1

If you go into the SAYR filter reset menu (touch the SAYR word on the screen then settings button 3 times) there are a few extra options like Max fan speed.

I set my Max to 50% and Min to 5% to quieten it down. There is also a fan/temp gain setting which adjusts how much the fan speed increases based on the temp spread between roof/house so you can make it so there needs to be larger differential in temps before it goes ballistic.

I wish I had known that before I took the system out! I never came across any mention of a secret hidden menu online but I have plugged it back in again to see and that would have been exactly what I was after.

tweake:

not sure about 12v. typically its 24vac or 240vac.

the simple way i did it is to use 24vac power supply. i use a simix 5856 diagram installed in the ceiling. set to your desired room temp. when ceiling temp goes higher than room damper opens to allow outside air. this also helps keeps keep the ventilation from shutting off from high ceiling temps.

Thanks tweake I'll have a look at that, the ones I saw on AliExpress were DC12v DV24v and AC240v.