Airtouch 5 and SmartVent Synergy

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kaczor47

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#316001 7-Sep-2024 13:12

I admit to being a bit of a noob to home automation, but I'll stick my neck out to post here...

We have a Smartvent Synergy (heat recovery) ventilation unit and are looking to add a ducted heat pump system. One option is to keep the Smartvent and pair it with either a Mitsubishi or a Daikin heat pump, controlled by an Airtouch 5 unit.

The Smartvent interface is entirely web based (the Evolve model), but I'd like to have a single point of control. So my question is: is there any way to drive the Smartvent system with Airtouch 5? (The Smartvent folks say no, but I wonder if there is a way to hack it...)

(Another option is to swap the Smartvent for a Losney ventilation unit, and go all Mitsubishi, in which case the problem of central control goes away, but this at a significant cost)

Cheers!

tweake

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#3279679 7-Sep-2024 13:33

simplest here is to keep them separate. let each system do its own thing.

i can see the point of using the ventilation ducts for the heat pump, good chance they will have to be increased in size and highly likely the vents are in the wrong place for hvac. so it may well be easier to install separate vents and ducts.

you can also do the ventilation duct so it dumps all the air next to the hvac return. ideally the heatpump will need to run in constantly on mode (i think mitsi's can do that).

or you can tap it into the ducts and use one way dampeners so when the hvac is off it can flow around the hvac ducts without blowing out through the return.

timmmay

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#3279692 7-Sep-2024 16:25

I control everything with home assistant, but there's a steep learning curve. There doesn't seem to be an integration for "Smartvent Synergy".

Integration will probably be difficult. I would probably also keep them separate unless there was a good reason, like having too many vents in the ceiling could be unslightly. You'll probably need larger vents.

In this thread (Airtouch info) there's a "Ventilation Integration" section. It's probably worth a quick read, it's two lines. In short, you could modify the ventilation system to push all the air out near the ducted system input and let the heat pump effectively do the ventilation.

tweake

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#3279693 7-Sep-2024 16:44

another thought here. by mem the mitsi uses a wired connection to the ventilation system. odds are its a simple voltage input. find what its looking for and see if the smartvent has that voltage output when running.

the smartvent should be running continuously anyway, which means the heatpump should be set to run on low fan speed continuously.

kaczor47

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#3279715 7-Sep-2024 16:55

Yeah, the idea was to integrate the two as follows

Mainly to avoid having the units separate since there is little space in the roof cavity, plus, as suggested, I don't want so many vents...

But let me skim that 'two line' post, I might have to reconsider...

Thanks!

timmmay

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#3279719 7-Sep-2024 17:07

The post is quite long. The section I was referring to was fairly short.

tweake

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#3279728 7-Sep-2024 17:37

kaczor47:

Yeah, the idea was to integrate the two as follows

Mainly to avoid having the units separate since there is little space in the roof cavity, plus, as suggested, I don't want so many vents...

But let me skim that 'two line' post, I might have to reconsider...

Thanks!

you still need a heat pump that can be set for continuous operation as the ventilation should run all the time. or fit it with dampers so it doesn't back feed the heat pump and go out the return filters.

i would recommend as close to equal duct runs as you can. at low air flows you can get far more ventilation air going into the shortest run.

also don't put the ventilation air intake by the garage. keep it well away from the garage, fireplace and range hood.

make sure you put decent returns for the bedrooms. undercut doors is ok but you can get noise. you may want to look at door vents or jumpers. but with only 3 brms you could duct the returns back to the heat pump.

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kaczor47

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#3399606 3-Aug-2025 18:04

Just wanted to circle back in here and post a follow up.

I ended up replacing the Smartvent with a Lossnay and pairing it with a Mitsubishi ducted heatpump, all controlled by Airtouch 5. I also have a Home Assistant integration which is work in progress, but looking promising.

Very happy with the setup, except for the fact that I didn't get a bypass. Wish the installer told me about how hot the spill zone can get. Thinking of adding it.

timmmay

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#3399635 3-Aug-2025 19:30

A bypass is the best solution. I didn't get one for my Airtouch 4. I have a series of automations here that does direct damper manipulation to reduce spill, basically by overriding the decisions the Airtouch makes and leaving room dampers open a bit longer. It has 99% fixed the spill zone overheating problem for me. The automations depend on being able to tell if the outdoor unit is running, which I do with a Shelly device, but maybe you can tell another way with your Mitsubishi or maybe you can tweak the automations to work without that.

kaczor47

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#3399696 3-Aug-2025 21:14

Nice - I'll have a closer look. Thanks!

One thing I want to try is to modify the AirTouch 5 'auto' mode to disregard the cooling function. We're in Wellington and never need to cool our house. I just want it to cycle between heating and fan modes. I achieved this with Home Assistant, but my wife doesn't want to touch home assistant!

timmmay

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#3399698 3-Aug-2025 21:39

I never use use auto mode. I use heat for heating, fan for ventilation, cool for cooling in summer which we use quite a lot for north facing rooms.

My wife won't use HA either.