Panasonic vs Mitsubishi ducted heat pump and ventilation solutions

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229 posts

Master Geek
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#3460974 12-Feb-2026 12:26

AlDrag:

AklBen:

Which smart home automation/assistant stuff works with the Mitsubishi ducted system with wifi control?

Anyone have any experience with it?

Home Assistant. I have the wifi controller from Lossnay working great with it. I think it's the same controller. I just bought and installed it myself.

Does the wifi controller install on the unit in the roof space? just moved into a new house, has Lossnay with Fujitsu ducted system, but no wifi for either (i think) assuming i need to go into the roof space and check?

AlDrag

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Ultimate Geek
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#3460986 12-Feb-2026 13:21

razor2000nz:

Does the wifi controller install on the unit in the roof space? just moved into a new house, has Lossnay with Fujitsu ducted system, but no wifi for either (i think) assuming i need to go into the roof space and check?

For my Lossnay (ERV) and heatpump, yes. Although the cable is pretty long, I could probably put it low in the attic to avoid getting too hot.
Assuming you have an HRV, I think it might have wifi built in? Otherwise not sure.

AlDrag

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Ultimate Geek
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#3464538 25-Feb-2026 11:13

timmmay:

I suspect your minimum opening could be another suspect. Turn that off first, that's definitely going to overcool particularly when combined with auto mode. You don't really need fresh air 24/7, we just run the old ventilation system which has an outlet near the ducted system inlet 4 hours a day with the system on fan mode, that's good enough.

I have no experience with bypass dampers unfortunately. If turning off minimum opening doesn't work I would suggest giving economy a try, based on the description above you probably don't want the AC sensor used at all, just the room sensors. I think Economy will just turn the outdoor unit off when the rooms reach temp, which is what I find. With a spill zone, system set to economy, when the room sensors reach target I can confirm the outdoor unit turns off. I was directed to do this by Polyair support, but for my system with a spill zone. It's definitely worth a shot IMHO.

I'm guessing "Sensor Off" means a zone being disabled.

Third option, consider whether direct damper control could help. With a spill zone, I find the dampers get closed way too early causing spill and overheating / overcooling. I directly set dampers in some conditions and it helps hugely. I can provide sample code - PM me if you want it.

Fourth option, which I don't like, but you could set the setpoint high like you say based on HA and room temperatures, then put it back down when you need additional cooling. I do a variation of this as we don't often need overnight cooling. I have HA monitor room temperatures, when they go over my threshold they turn air conditioning on for 30 minutes, then turn it off again. That usually only happens once or twice on a hot night.

The other configuration I changed on my Daikin heat pump directly is to prevent air circulation when the system is up to heat or down to cooling temp. I didn't like the breeze it put through the rooms constantly.

I also change my spill zone based on whether I'm heating or cooling, just because of the layout of our house.

I'd be interested to hear how you get on.

I now have the minimum opening just for 30% for 1 room (to avoid stuffyness overnight) and use Economy mode. Even now trying Economy mode with "Spill" in the hallway and I think I prefer this most, as it cools down the hot stairwell overnight (it's always so hot there).

I contacted Airtouch about the confusion around their manual description in Economy mode, and yes, as you say, it purely uses the Zone sensors, which is exactly what I want. I've observed that on a cold night, the compressor does fully turn off when the temperature of my zones are at least 1 degree below the Set Point (I think).

In regards to my ERV. I'm skeptical whether it's doing the job. If I turn off cooling and enable fan, the dew point seems to always match outside, maybe 1 degree less. I need to get more data on this though. Perhaps my house just doesn't need a ventilation unit. Although I'm tempted to set it up with dedicated ducts...
At the moment, I turn it off during the day, as it's too hot in the attic. I observed however that it still pulls in air from the air intake of the ERV, as it has no backdraft damper. Not a massive amount, but enough to notice if I remove the duct and put my hand in it. I've bought a backdraft damper though, so might install that on the ERV's supply spigot.

My next steps are:

install ERV supply backdraft damper.
redo all my ducting so it's the insulation is properly sealed! Reduce harsh bends and not have the zip ties crush the insulation.
insulate the supply/return plenums and box. I don't know what insulation to buy, so need to research on that.
maybe remove the bypass damper in favour of spill. Might give me a bit more airflow, as less ducting.
buy/install some double honeycomb blinds from Aliexpress for my windows. I think my window furnishings are garbage. I can feel the heat right through them and it's a lot of heat.

I do think my airflow is really poor though. Going to my neighbours house (although smaller) his bigger unit feels amazing. It's like heaven in there. Where mine, you can barely feel the airflow. Maybe a good thing if you're in the room for a long time though.

@timmmay I'm keen to see your custom code for home assistant airtouch control if you want to share. Even if I don't use it, I'm curious, as a programmer myself.

timmmay

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#3464791 25-Feb-2026 16:13

@AlDrag Don't remove the bypass damper, you don't want spill. I don't recall the details from way back, what make / model of air conditioner do you have? With Daikin you can adjust custom functions to increase airflow, it's fiddly and usually done by a technician. If there's not enough airflow I wonder if it's something weird with the ERV. Rather than doing all this your installer should be working it out, though I think many are relatively inexperienced and don't have the time - they quote to chuck it in not to get it all working properly so time they spend perfecting it is money lost not doing other work.

AlDrag

282 posts

Ultimate Geek
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#3464793 25-Feb-2026 16:18

timmmay:

@AlDrag Don't remove the bypass damper, you don't want spill. I don't recall the details from way back, what make / model of air conditioner do you have? With Daikin you can adjust custom functions to increase airflow, it's fiddly and usually done by a technician. If there's not enough airflow I wonder if it's something weird with the ERV. Rather than doing all this your installer should be working it out, though I think many are relatively inexperienced and don't have the time - they quote to chuck it in not to get it all working properly so time they spend perfecting it is money lost not doing other work.

The spill might only be an issue in winter, making our house too cold. In summer it works well though. Just seems inefficient having the bypass damper, which is a decent length of ducting, sitting in a super hot attic.
I have a Mitsi PEAD50. I already adjusted my static pressure at the second highest setting. I assume the higher the pressure, the less time the air sits on the coils? Thus reducing effectiveness of the condensing? Or maybe I'm wrong there.
It's definitely possible the ERV is interupting the airflow. Since the ERV supply is ducted right onto the heatpump's return plenum.

I am thinking about contacting the installer again. I just feel embarrassed as they're probably so sick of me haha.
But yes, they're one of those installers that don't really know much about HVAC. I mean, they just zip-tied on the outside of the duct onto the spigots without tape. So crushing the insulation. But maybe most do that here.

AlDrag

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Ultimate Geek
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#3464796 25-Feb-2026 16:26

I just realised, setting my set point LOWER than I want it during a hot day (like today) and the supply definitely pushes out colder air.

I guess because the unit is in a very hot attic and the central return is sucking in hot hallway airway air (usually 27 degrees), then the compressor must not run fast enough to overcome those conditions, since it thinks it just needs to cool a room by 1 degree.

I'm not sure what you are supposed to do in those situations. Maybe an offset setting? But then at night it's a different situation...

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timmmay

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#3464846 25-Feb-2026 20:12

I have a power meter on my heat pump. The further your setpoint is from current temperature the more power the heat pump uses, and the colder / hotter the air comes out.

With faster airflow I guess does spend less time in contact with the coils, but there's more air going past. Not sure what's better there. But if you can't get things working maybe more airflow will help.

Maybe you need to pay a real expert to look at it for you.

tweake

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#3464850 25-Feb-2026 20:20

AlDrag:

I just realised, setting my set point LOWER than I want it during a hot day (like today) and the supply definitely pushes out colder air.

I guess because the unit is in a very hot attic and the central return is sucking in hot hallway airway air (usually 27 degrees), then the compressor must not run fast enough to overcome those conditions, since it thinks it just needs to cool a room by 1 degree.

I'm not sure what you are supposed to do in those situations. Maybe an offset setting? But then at night it's a different situation...

if its only a few degrees its probably because it variable speed pump. most will slow down when they get close to set point. that way they can constantly run at a slow speed which is generally more efficient. often there is a "power mode" or "powerfull" that will make it act like an old school compressor and go hard out until set point.

AklBen

136 posts

Master Geek
+1 received by user: 43

#3466985 5-Mar-2026 12:48

As we've had a few cooler days, we've used the heat function of our ducted system, installed in early January.

We have a rule set up in the Mitsi app that, after 11 pm, if the house temperature drops below 20°C, it will turn on the heat.

We've noticed that:

a) It's getting too hot when it's set at 20°C.
b) turn the temp down to 19 or 19.5, and it's draughty and feels cold.

I am slightly annoyed that the Mitsi ducted system doesn't have a quiet fan mode or just a lower fan setting. The lowest fan speed feels too strong.

Any tips from anyone? Should we just leave it at 20c from earlier in the evening or?

timmmay

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#3467123 5-Mar-2026 19:56

I find ducted systems work better when left on for longer periods, rather than turned on and off when required. Having said that, I do have it turn on air conditioning if it gets too hot in summer and it's not already turned on. On colder nights though I find it better to just turn it on earlier with the rooms set to the target temperature and leave it alone. What you're doing should work... but if it's not, give that approach a try.

tweake

2664 posts

Uber Geek
+1 received by user: 1141

#3467138 5-Mar-2026 20:34

AklBen:

As we've had a few cooler days, we've used the heat function of our ducted system, installed in early January.

We have a rule set up in the Mitsi app that, after 11 pm, if the house temperature drops below 20°C, it will turn on the heat.

We've noticed that:

a) It's getting too hot when it's set at 20°C.
b) turn the temp down to 19 or 19.5, and it's draughty and feels cold.

I am slightly annoyed that the Mitsi ducted system doesn't have a quiet fan mode or just a lower fan setting. The lowest fan speed feels too strong.

Any tips from anyone? Should we just leave it at 20c from earlier in the evening or?

i would go get some temp sensors and place them in the rooms and see what actual temps your getting.

also get a Vane Anemometer and measure the airflow speed coming out of the grills. there is typically a range you want it to be in so you get good throw and mixing without going so fast it feels drafty.

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AlDrag

282 posts

Ultimate Geek
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#3482019 18-Apr-2026 21:18

I just found out my return plenum is installed like this! Oversized, so they just forced it on with tape lol. I posted it on "My Efficient Electric Home" Facebook page, and everyone is having a laugh...standards must be higher in Aussie or I just got bad luck haha. They're even laughing about the wire mounting.

tweake

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#3482082 19-Apr-2026 12:43

omg :(

sorry you have had to deal with such clowns. this is the problem, the sales people talk the talk and the installers do the dirtiest cheapest job and the sales people don't care if it works or not.

the service side is treated as a cost, so its done on the cheap. poorly trained low wage staff who know stuff all about the equipment or how the job is meant to be done.

AlDrag

282 posts

Ultimate Geek
+1 received by user: 29

#3482084 19-Apr-2026 12:48

tweake:

omg :(

sorry you have had to deal with such clowns. this is the problem, the sales people talk the talk and the installers do the dirtiest cheapest job and the sales people don't care if it works or not.

the service side is treated as a cost, so its done on the cheap. poorly trained low wage staff who know stuff all about the equipment or how the job is meant to be done.

Yep...I wish I knew. I would have tried to find actual HVAC people. I learnt my lesson. The owner is usually nice at least...

This install has cost $$$ and almost getting as stressful as my house purchase haha. Next time, I will just get splits.

I assume I'd be in the right of asking for this return plenum to be done properly? I might get laughed off, but I can try.

Strangely enough, after doing some research, seems like the plenum should be a lot thicker too, to maximise performance, otherwise the entire coil won't be touched by the return air. But looking online, I can only find thin plenums. hmmmmm.

tweake

2664 posts

Uber Geek
+1 received by user: 1141

#3482085 19-Apr-2026 13:01

@AlDrag this might be interesting https://youtu.be/prllbzLfmaA?si=BCc0o6OZZVleuHoY

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