In June 2021 commenced our journey exploring the iZone HVAC zone control system as part of a upgrade from a pre-existing Hitachi ducted utopia inverter over to a compact MHI KX Series high efficiency 3 phase inverter which was recommended and sold to us via the local iZone distributor.
The original 8 zone IAS manual control system was upgraded to use an iZone 435 controller, operating 11 zones with the remaining 3 zones in the end used for a constant zone and 2 zones consumed to run a fresh air intake. Ductwork changes were made with a new plenum box installed (pressure box system).
Unfortunately since June 2021 the system remains not yet working the way it was designed with numerous issues that we have lodged with the iZone company and we are patiently waiting on resolution.
On the flip side the MHI has been an interesting unit, hampered in performance we believe by the iZone but the design worth some discussion.
This blogs lists the challenges to help iZone solve these issues and also give insights to how the hybrid system performs as many people have asked me for insights on use of a zone control system give how little information exists on the options on the market, there are virtually no detailed reviews on any of the systems out there.
I am also keen to connect with others exploring these types of automation systems, as a specialist in this area always keen to try out new products and approaches.
Core benefits of iZone
The iZone control system allows for more than 8 zone control so allowed an update from 8 zones to 11. (Sales team claim 14 zones but as I will explain this isn’t really true) Most HVAC systems today run with architectures that are decades old due to I believe lack of investment in this industry, the 8 zone limitation is a common issue with options in HVAC residential installations.
Other benefits:
- The control system supports a very basic automation protocol
- Can work with a variety of zone motors (in theory) not tested
- Possible in theory to change the interface board if changing the HVAC units so likely not throw away if replacing the compression/fan coil.
- iZone claim to support of a few models of a few brands of HVAC.
- Zone control systems all claim to be able to improve overall efficiency of a non-zoned system by about 35%. No doubt this possible as logically running all zones on will cost more than partly air conditioning a home though with a lot of caveats and “in theory” comments and we’ve see no data confirming any of this.
Real world problems (short list)
We have a increasing list of defects which have not been resolved yet by iZone which I think anyone considering this system should be aware of and also may be of use to anyone thinking about developing their own control solution. The real world problems we’ve hit include but are by no means limited to
- Slowness of support from iZone, since June 2021 (now late December 2021) iZone has not fixed a single issue, some help has been provided by the distributor but still no issues fixed and even they are frustrated with the lack of support they have gotten. We are not sure why this is the case, a couple installers made claim to responsive support which did form part of the decision to use this system. This level of support is unacceptable under Australian Fair trading laws and certainly for most people is a key deciding factor with such a large investment (iZone systems costs many thousands to install).
- The control system is simply incompatible with Mitsubishi Heavy Industries. This is especially true of 4 fan systems (their recent systems) The system is configured for 4 fans but the touch interfaces cannot see the MHI boost mode [fan 4] though latest testing shows its much more serious than this I believe it cannot control the fan properly at all. Only the app and schedule is even aware of the boost option but the main controller overrides it to a 3 fan view. MHI system runs in a crippled 3 fan mode and we believe this issue also explains why it takes nearly 1 hour to heat the home on cold days even though our system is oversized for the home and blows very hot air from the vents (around 46C in duct temp). When we spoke to the MHI technicians based in Australia they were off the view the system could bring a medium size home like ours to temp in minutes. The old Hitachi system which was much smaller with less operating range also took 1 hour to hit temp but the key difference is the system did not generate a hot vent temperature (30c at the vent was a struggle for Hitachi) so the slow ramp at least made sense. MHI’s higher Boost fan speed is designed to rapidly bring the home to temperature so we confident now that the iZone is at fault for both not recognising the fan speed and subsequently not allowing the MHI to rapidly warm the home in summer. In cooling the iZone is simply unable to cool our home which we discovered only now we’ve entered summer. Note our initial plan was to use a new Panasonic ducted unit however after being told by Panasonic technicians that iZone was reported to not work properly with their current range we pivoted to MHI, so what brands are compatible is unclear.
- The system was deployed with a mis-mash of old firmware version and different versions of parts, not even sensors had the same version of were the same colour. [e.g. mix of black/white coloured sensors with firmware 1.3 and white/white sensors with firmware 1.4, even broken clips on the sensors]
See image below.. these are both “WHITE” sensors (blacks the face is black but the colour of the sides of the unit and age of circuits is luck of what stock you get)
Youtube video also available here https://youtu.be/1dwYdqKzRiw - Firmware on any component CANNOT be updated over the wire, or by end user or even by the installer! Best option is ripping out components and sending them back to iZone for replacement just to update firmware but of course how realistic is this to be allowed ongoing and at what cost? This has the potential to be a major problem as the system was made up of older firmwares with no idea if updated firmwares might resolve some of the known issues. iZone was unable to provide a basic list of current firmwares with release notes. They simply could not identify which firmware updates would fix what defect so months on and the system has still not been updated to at least versions that were current at the time of ordering. Ability to update firmware has been an expectation of basically all medium complexity technologies for years now to not have a way to update firmware on a system as complex as the iZone baffles us particularly given comments from iZone claiming firmware updates are possible by the user. Also if you look at low cost microprocessors that even hobbyists can use today these all come with firmware update capabilities. Despite firmware updating being a major claim by the iZone team we have checked and rechecked this and spoke extensively with the distributor on how it might be done. In real terms it is not possible, the components do not even have the appropriate pin headers for a firmware update to be loaded by a user or professional. (Image below taken from one of the faulty boards the installer had to remove from its case to fit it into the system, as you can see the place where pin header would need to exist for even a local firmware update is removed, see right side of photo. ) Those of you experienced with ESPHome may find this particularly interesting.
- System configuration can be changed without user input, we’d recorded cases of data being modified, such as when the zone airflow was change to 75% and target temps turned off. iZone claim their support people could not do it as the system does not support remote access (another thing we believed was supported but the distributor and iZone disagree with each other on this) We were never able to isolate how configuration data is being changed (see section on no monitoring) The section is password protected btw so it cannot be changed by an ordinary user.
- System occasionally will turn itself on, or off, or switch from heating to cooling with no user input (impossible to trace, see section on no monitoring) iZone have no method to identify and track such issues. (Yes I kid you not, a system this complex has no logging, audit function or any way to know if its operating correctly)
- Mobile App is generally unstable and unusual. The play store rating of 2/5 is very generous in my view given how poor this application works.
I’ve authoried a video on this (apologies for the shaky video) but if you carefully you can see the app commands are dropped by the system, e.g. close a zone and later on it reopens by itself. This is one of numerous issues with the app, so when people say its unusable this is why. (and yes my network is optimised, benefits of my profession)
https://youtu.be/gut1ewq67RA - The Ethernet interfaces are slow and unstable. We are told part of the problem is the wireless sensors are not sending updates more frequently than about 2 minutes to save battery. If this is accurate then this would explain poor management of temperature in the zones.
- The ethernet interface is actually normally connected wireless (so is not really an ethernet interface) To use a cable iZone charges $110 just for a basic cat5 type cable and there is no way to actually confirm if the cable has taken over from the wireless connection. In our experience no improvement in stability occurs when using the cable, but we were completely unable to confirm if the cable was actually being used after numerous discussions with iZone.
- The system regularly overshoots and not necessarily in areas you might be able to explain. We tracked this down to several issues firstly the touch interface temperature sensors are widely inaccurate vs a standard wireless sensor, this was a big surprise given the tablet is hard wired and extremely costly, each unit is nearly $1k so you’d expect a quality product not a cheap product. In additional even if the temperature is adjusted the tablet controlled zones overshoot more than any wireless zone, and overshoot by typically 4 degrees (the system claims accuracy around 0.5C).
Image below show the dining sensor relocated next to the living sensor (touch screen has it built in) if it was designed well they should track to the same temperature reading as they are in the same position. They do not. In fact not only do they differ by several degrees they do not track at the same difference over time. Touch screen sensors are not only inaccurate they overshoot far worse than a wireless sensor.
- Error reporting does not work. We’ve now seen the MHI generate several errors and the iZone fail to report the issue. The iZone system lost the ability to communicate with the MHI and required hard power off at the switchboard and restart to bring the system back into communication. The claim has been that the iZone system will pass any error message from the HVAC on through the tablet and allow the end user to see if the HVAC has an issue or iZone. This is a vital point as iZone is not compatible with the control system supplied by the HVAC manufacture so you are asked to remove the controller that normally reports errors in order for the iZone to work! I cannot see any method for isolation and diagnosing faults especially given iZone cannot work with the original controller in normal mode. We’ve already seen iZone makes diagnosing issues with its own components a nightmare as there is no method to its own components are connected properly, without data from the HVAC the system is a bit like a black box IR remote. Even issues like excessive defrost cycles cannot be seen in the iZone so core issues could exist with the HVAC and be hidden by the iZone. The distributor has recently (early December confirmed he now believes the MHI interface is simply incompatible with new models)
- Monitoring is completely missing. The system cannot tell you when the system was turned on or off, or by who/what device. Any data on operating power or efficiency, no information on zone status (e.g. if the zone is open/closed/part open), no information whatsoever is displayed or recorded or available from the app or ethernet bridge. All you get is set temp, what you set the zone to, system on/off requested, fan speed (set value not even actual) and mode (not even showing if in auto if the system has switched to heating or cooling) As such there is no direct way to see if the system is doing what it is suppose to or if the system is even overworking. In fact we’ve seen the iZone report system is on when its clearly off.
For power, you could attach separate current sensors onto the compression and then separately onto the fan coil combining that data and then trying to figure out what the iZone system is doing but this would be next to impossible using just iZone. (Yet we where “advised” all this was a “feature of iZone” hence vital to set the record straight, don’t believe what cannot be proven) - The environmental data used to “drive” the rules for deciding when to open the iSave fresh air system are completely inaccurate. In our setup we had two touch screens generating readings on air quality, the readings never matched to the data showing in the application and were not an average or other calculation based on real data.
- iZone recently has been building something called recipes. The name has confused everyone that has seen it wondering what food has to do with the iZone. It should be no surprise that the recipes are basically undocumented and the ones tested so far do not work correctly. e.g. using air condition on condition generates a flood of messages and using the alternative approach generates random messages. Unusable. Similarly the commands to control environment don’t appear to consider the basics such as the possibility that temperature might change more than once in a day. In any case the capability is undocumented and not useful in its current form.
- Fresh air option is not well thought through, no manuals were provided, probably do not exist, and basics like how to remove and clean the filters hasn’t been considered. The filter system uses 2 vform type filters but its not possible to extract the second filter for cleaning. Also unlike the other fresh air products on the market there is no sensor at the roof cowl that detects the air temperature and allows for adjustment of air flow based on actual temperature differences. The system despite being controlled by a variable zone motor controller locks to on or off and no ability to variable the airflow either. In hindsight it may have been better to go with a dedicated third party solution for fresh air.
Initial Expectations
I must admit our expectations after repeated talks with the iZone sales team, engineering and authorised installers were extremely high, claims included firmware was updateable by end user so new features would “flow” through, able to control, monitor and automate it as we wished, fully compatible with MHI and Panasonic, can run 14 zones etc.
Unfortunately as I noted before not many reviews exist and we acted on faith and trust in the iZone claims, hence why this article is being written to help others get the facts. Apart from one outrageous youtube video that scores the system 9/10 and claims it to be mature there isn’t much else available and we found the “installers” claims where not based on them using the system but what they were told by their sales rep.
Limited zones
The first big issue we fast after committing funds to this upgrade was the 435 controller is advertised as supporting 14 zones however 2 zones are lost using the fresh air and there is no method to work around not requiring a constant zone. So basically add iSave and the system drops to a max 12 zones but really its 11 because of the constant requirement.
Late sharing of this vital information from the iZone team forced a redesign just before we started laying new ductwork as advise on the izonepedia was invalid. Unlike other systems such as the Advantage Air myair5 there was no way to allow excess air pressure to flow to a common area without losing key functions like temperature control.
The air overflow requirements so extreme that even though we already had designed in two 12/14 inch ducts to common areas this was not BIG enough for iZone so our 2 common zone layout had to be augmented at the last minute losing the 12 zone to the iZone archaic bad air flow management. (a fixed zone had to be put in running from the return to the supply which iZone would “manage”) Yep.. thats is right.. air is routed straight from the fan coil back into the return!
Note if you have committed to using iZone or any other system that hasn’t got enough zones please never use common zones. The reason for this is the common zones are not managed and cannot be managed in any way (don’t believe installers than think you can “manually” control them), Common zones will blow air at whatever temperature the supply is at, and this can make those zones very uncomfortable. If iZone was not limited now to 11 zones first thing I would do is remove both common zones and put in zone motors. Again to reiterate as this is an important point I did not appreciate! Once you have temp control having fixed zones is not like the experience of a manual zone control system. Fixed zones become the obvious area where air temps are not controlled and airflow not controlled, the MHI pumps out ~46C+ and ~6C in summer those zones become uncomfortable/unbearable. If we had a choice again we’d have stopped the install and rethought the design rather than having introduced a fixed zone to compensate for iZone not providing the advertised 14 zones. Another option might haven been 2 smaller units, 2 zone systems and run upstairs and downstairs independently to get around the 11 zone limitation. (or buy another system of course)
Old school constant design costs another zone
Constant zone is an old design where air is pumped between the supply and return out to a fixed location if too many zones are closed. Other zoning systems like Advantage Air use an approach of allowing a percentage of air to flow out of vents to instead direct extra air actually through the system. This gives you an extra zone and avoids the need for air to be pumped needlessly into the return or out to another room. Unfortunately at design time we didn’t know a dedicated constant zone was unavoidable and had been told 2 commons zones would do the job. If your looking for a system focus on getting a detailed understanding of how the system deals with excessive airflow when ramping down and if its got a common zone concept get the exact size of the duct requirements.
Poor design / UX
One issue that was almost a show stopper when we went to purchase was the poor design of switch sensors. iZone must have a sensor in rooms it is going to temp control and iZone only offer 1 style of sensor which is a button sensor that looks exactly like a wall switch (Clipsal Saturn series) Unfortunately Clipsal Saturn series are not in every home, thank godness as they are cheap/nasty looking and collect finger prints. Because the sensor is the shape/size of a wall switch they are easily confused with light switches. This means, visitors, kids, elderly will confuse the climate button with a light switch and randomly turn on/off your zones in an attempt to find the light switch. They also look terrible if you have a different series of switches such as a Neo series or even basic classic series light switches. A hodge podge of switches all over your walls ultimately devalues your home when you consider re-sale value. We have had to avoid mounting any of the sensors because of the awful design issue.
I did raise this through to iZone however iZone (Walter) declined to have a discussion on the topic. They were that reluctant to consider any changes, not even willing to talk about why the sensor switch was not ideal. This should have been a red flag on dealing with iZone further I admit now.
Anyway I really want to highlight, the sensors look bad, and are confusing. If you are looking at this system consider this and insist on seeing samples placed in your home before making a decision.
In any case we are considering investigating design of a new small and less obstructive paintable enclosure similar to the Advantage Air one using a 3D printer if I can borrow a spare sensor and get it across to my 3D printing guy. Note a priority but something on the backlog if we ever get the primary issues solved.
App Design
I could easily write an entire series of blogs on the mistakes and issues on the design of the mobile / tablet app which despite efforts to integrate this system to other platforms still remains the only other way to control it other than using a touch screen. Image below is probably what I’d consider to “sum it up” in photo. If you want to know more about the app I’d start another blog on that.
Note I am experimenting with code for Home Assistant, Openhab and also have tried the Alex and Google integrations. The integrations managed by iZone don’t work properly. The Home Assistant code is not bad, but of course impacted by the problems with the ethernet interface.
Fresh air
The fresh air also does not work wireless or independently like the original advantage air 4 button system [which is cool and I wish we had been able to source it] The iSave instead uses 2 full zone inputs off the main controller as dumb on/off switches. It also has no temperature sensor on the air intake or filter sensors.
Recommendation and Next Steps
We continue to wait to engage with engineering and support at iZone with pressure being applied by the local distributor. I suspect most readers would be wondering why we’ve not gone to consumer affairs yet, however at this stage I am still hopeful we can get a resolution and maybe help them bring their product to be fit for use and we believe the distribution is behind us. At the moment not a lot of options on the market and would be good to see a semi-local organisation providing a fit for purpose option.
I’m keen to hear of others experiences and other system options for zone control. I’ve spent some time thinking through the work required to design an open platform zone control solution that could do what iZone does but be flexible and easy to update and I believe it would be achievable using off the shelf components and software. iZone just are not investing in R&D as can be seen by their inability to read error codes or control the fan speed. The MHI protocols are probably the main challenge for anyone however from what I’ve seen iZone don’t appear to have figured this out properly and with their inability to update firmware this is a could eventually be the death of their business. Using an open platform the solution could be dynamically updated to refresh the protocol and the community could support each other as occurs with the automation platform ecosystem. Be an interesting project to build an intelligent zone control system.