Panasonic vs Mitsubishi ducted heat pump and ventilation solutions

Forums › Home Workshop DIY › Panasonic vs Mitsubishi ducted heat pump and ventilation solutions

1 | 2 | 3 | 4 | 5 | 6 | 7 | ... | 21

247 posts

Master Geek

#3308237 12-Nov-2024 18:49

tweake:

make sure you go through with them on how it will be installed. sales people will talk bs all day long and poor installation can turn a good system into a crap one.

how are you going to get ducts to the rooms? multi storied? how do you get it to the other story?

i assume the indoor unit will be installed in the ceiling space. there is always the issue of duct leakage. which means the heat pump pushes air out of the house and the house sucks in air from outside or the neighbors house. one reason you want to make sure the house is under pressure.

I did have 2 different installers come in for a more detailed quote and an idea of what they'd do.

So it's 2 storey, but just going to duct the top floor. The bottom floor is fully open plan and is covered by an existing panasonic split.

We have a pitched roof with lots of room (supposedly) and thus the installers so it's not problem installing up there.

(It's an end terrace home in Auckland. Master bedroom faces the east, the other 2 bedrooms face the west. We have a shared wall facing north).

timmmay

20578 posts

Uber Geek

Trusted

Lifetime subscriber

#3308239 12-Nov-2024 18:52

AlDrag:

I have read it. Just read it again, and yea maybe I should avoid Panasonic....our existing heat pump downstairs is Panasonic though, but that's fine...just a regular wallsplit.

I've read that a lot of people are happy with their ducted system without zone control...but obviously read some like you that weren't, so unsure if I want to spend the big bucks to get AirTouch5. Supposedly the Mitsubishi gets basic zone control though...

I was thinking about multi-split, but I don't like it aestheitcally. We have 3 really small bedrooms (about 3 x 3.2) and thus want to keep the walls free from any splits. I also want Lossnay (Maybe that can be integrated into splits though).

I know one or two people with ducted systems without temperature control who are happy as well. I suspect it depends on the house and sun and such. If one side of your house is regularly much warmer than the other I suspect many people could be unhappy without automatic temperature control. It was bad enough we had the Panasonic system removed, both because of temperature control and noise. Standard heat pumps are simpler systems, Panasonic may be able to do those ok.

Basic on / off zone control would be the absolute minimum, but you'd probably find you're constantly messing with it trying to get temperatures right. If it can integrate with Home Assistant you may be able to automate it yourself, but it would be a fair bit of work.

With ducted systems you need vents in the doors or walls, or doors undercut by at least 1cm preferably 2cm. The ones I got / linked to have worked really well, but they can't be too small either, those systems can put a lot of air through if you are trying to make a large change in temperature. Supply dampers are really important as well, the square ones I link to are effective.

Ducted is definitely more complex, and easier to get really wrong than high wall heat pumps. My wife hates the ducted system, partly because of the hassle of getting it installed and working properly. She grew up in the UK and likes radiators that don't blow air around, but they don't have cooling which I think we need these days.

AlDrag

247 posts

Master Geek

#3308240 12-Nov-2024 18:59

timmmay:

I know one or two people with ducted systems without temperature control who are happy as well. I suspect it depends on the house and sun and such. If one side of your house is regularly much warmer than the other I suspect many people could be unhappy without automatic temperature control. It was bad enough we had the Panasonic system removed, both because of temperature control and noise. Standard heat pumps are simpler systems, Panasonic may be able to do those ok.

Basic on / off zone control would be the absolute minimum, but you'd probably find you're constantly messing with it trying to get temperatures right. If it can integrate with Home Assistant you may be able to automate it yourself, but it would be a fair bit of work.

Yea that is a concern. 1 bedroom facing the east and the other 2 facing the west...maybe I just need to spring out the dosh for AirTouch5....to be fair, it can be retrofitted later.

I really hope they calculate the unit size correctly. That would be frustrating otherwise...

timmmay:

With ducted systems you need vents in the doors or walls, or doors undercut by at least 1cm preferably 2cm. The ones I got / linked to have worked really well, but they can't be too small either, those systems can put a lot of air through if you are trying to make a large change in temperature. Supply dampers are really important as well, the square ones I link to are effective.

Yea, I haven't actually done a measurement, but the door gap seems a lot higher than my existing 1970s rental. Could probably fit a finger under it, or at least almost could.

timmmay

20578 posts

Uber Geek

Trusted

Lifetime subscriber

#3308256 12-Nov-2024 20:23

An Airtouch can absolutely be fitted later. I suspect it will be cheaper to do when the system is originally installed, as it will prevent rework and throwing things away that aren't needed.

Regarding sizing, having a unit too large is possibly worse than having a unit too small. Read about the spill concept on the big thread I wrote. Having a really low minimum output can be really useful for ducted systems. Ducted systems are better turned on using timers and automation so the house is the temperature you need it when you get home, rather than turning it on and getting it heated or cooled right now. Of course they can be used either way, but using it with timers and such means you can have a smaller outdoor unit, lower minimum power, and less spill. If you can, go for the spill damper or whatever it's called, as the spill zone is annoying.

Almost a a finger width isn't enough for the air for a ducted heat pump to return. 2cm is more is recommended. The wall return grills we use are something like 30cm wide by 15cm high, area of 450sq cm. If your door was 70cm wide that would require a 6.5cm door undercut which is pretty impractical - assuming I can do basic maths. Even with the 30 x 15cm grills sometimes when things are on high the air goes through so fast they make a low whistling / moaning type noise. You can also do one return per room, but then you have the input diffuser and return diffusers on the ceiling, there's a risk the air just goes across the ceiling and doesn't help the room temperature much. Even with a downjet source diffuser the air is going to go diagonally across the room, whereas with a return vent down low it's drawn across the room.

tweake

2391 posts

Uber Geek

#3308263 12-Nov-2024 20:38

timmmay:

Regarding sizing, having a unit too large is possibly worse than having a unit too small. Read about the spill concept on the big thread I wrote. Having a really low minimum output can be really useful for ducted systems. Ducted systems are better turned on using timers and automation so the house is the temperature you need it when you get home, rather than turning it on and getting it heated or cooled right now. Of course they can be used either way, but using it with timers and such means you can have a smaller outdoor unit, lower minimum power, and less spill.

they should never be sized for heating up the place from cold. they are sized for the load, typically 99% day, so it s not even sized for the coldest day and even then its running 100% to MAINTAIN temps on the almost coldest day.

unfortunately the problem is most of our homes are so bad performing its cheaper to let them cool down then reheat.

the better the house the more constant the heating needs to be, because the heat pump sizing goes down. which makes it harder/longer to heat it up from cold.

AlDrag

247 posts

Master Geek

#3308265 12-Nov-2024 20:45

timmmay:

Regarding sizing, having a unit too large is possibly worse than having a unit too small. Read about the spill concept on the big thread I wrote. Having a really low minimum output can be really useful for ducted systems. Ducted systems are better turned on using timers and automation so the house is the temperature you need it when you get home, rather than turning it on and getting it heated or cooled right now. Of course they can be used either way, but using it with timers and such means you can have a smaller outdoor unit, lower minimum power, and less spill. If you can, go for the spill damper or whatever it's called, as the spill zone is annoying.

So I think you mean a spill damper that allows variable damping opposed to only full on/off bypass? Wonder if Airtouch has that variable damping?

timmmay:

Almost a a finger width isn't enough for the air for a ducted heat pump to return. 2cm is more is recommended. The wall return grills we use are something like 30cm wide by 15cm high, area of 450sq cm. If your door was 70cm wide that would require a 6.5cm door undercut which is pretty impractical - assuming I can do basic maths. Even with the 30 x 15cm grills sometimes when things are on high the air goes through so fast they make a low whistling / moaning type noise. You can also do one return per room, but then you have the input diffuser and return diffusers on the ceiling, there's a risk the air just goes across the ceiling and doesn't help the room temperature much. Even with a downjet source diffuser the air is going to go diagonally across the room, whereas with a return vent down low it's drawn across the room.

My finger is about 1.5cm, so maybe it is 2cm, but again, I never measured or put my finger under it. I will need to check. Both guys that I got to quote/check said it was fine, but they never measured it either and I don't think they care about the details (which annoys me).

I'm planning on getting a bigger return than that. It'll be 750x550. Just for reducing noise.

timmmay

20578 posts

Uber Geek

Trusted

Lifetime subscriber

#3308287 12-Nov-2024 21:24

Nah, it's called Spill or Bypass mode in the Airtouch 5 installer manual (which is easily available online AFAIK). Have a read of my thread, and I'll copy the text from the installer manual below. Basically, one room only needs a small amount of power it might open the damper for the room 20%. The minimum output is 100%, spread across all dampers. That 80% can either be dumped into your spill zone (often a lounge or similar), or it can go back to a bypass damper so it basically loops around through the heat pump again.

When you think about returns, there's two types to consider. The main return damper is usually quite large, from memory ours is 1m by 0.7, and the larger they are the quieter they are. The one with the Panasonic was smaller and louder than this one. You also have to provide a route from each room back to the return damper in the form of an undercut door 2-3cm high or a door / wall vent, unless there are small per-room returns.

Anything not done quite right impacts the performance of the system and the comfort of the home. The problem is finding a good installer can be difficult - high volume doesn't mean they know much about it. I think the best way to find a good installer is word of mouth. The way I found one was I called Daikin NZ up and asked them who they recommended.

Airtouch 5 installer Manual section 5.5

Spill or Bypass mode is a safety feature of the AirTouch 5 system to prevent pressure from building
up and causing duct damage. This usually occurs if someone has turned off all zones while the AC
unit is pumping air into the system leading to a pressure build-up (and potential of duct puncture,
blow-offs or joints splitting).

It is designed to automatically open dampers if someone attempts to shut down all dampers thus
preventing pressure build up.

Spill function opens the zone(s) chosen as spill zone(s) in the system when all zones are closed.
The system will maintain the number of zones chosen as spill zones open at any time when AC is
running. For instance, there will be at least two zones fully open if two zones are chosen for spill. The
first zone in the chosen spill zone list will open first to spill. The maximum number of spill zones is half
of the total zones.

When choosing zones for spill, it is strongly recommended NOT to use bedrooms as spill zones.
During sleep time if the air conditioner is on and spill zones are forced to open, the spill zones will be
very cold or hot.

Bypass function opens the bypass damper which connects the supply duct to the return duct directly
when all zones are closed. Each AC unit only has one bypass damper.

IMPORTANT: Always set at least one spill zone unless there is a permanently open zone used as
spill zone. Otherwise, all dampers will be able to close and damage may be caused by high
pressure building up inside ducts

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

AlDrag

247 posts

Master Geek

#3308289 12-Nov-2024 21:31

I will have a proper read of your thread now. Sorry about that.

timmmay:

Nah, it's called Spill or Bypass mode in the Airtouch 5 installer manual (which is easily available online AFAIK). Have a read of my thread, and I'll copy the text from the installer manual below. Basically, one room only needs a small amount of power it might open the damper for the room 20%. The minimum output is 100%, spread across all dampers. That 80% can either be dumped into your spill zone (often a lounge or similar), or it can go back to a bypass damper so it basically loops around through the heat pump again.

I thought modern outdoor units now a days have "Inverters" and thus can vary their power? So why does it have to run at a fixed output all the time?

Edit: Just read your thread. Makes sense now. I guess if the room needs to be heated/cooled quicker or the low power setting isn't sufficient enough to overcome room leakage or whatever, then it could spill. Surprised that would be a problem in a very well insulated home though. I would have thought the low power mode would always eventually get to the desired temp.

Edit2: Your solution with your positive pressure system is very clever!

tweake

2391 posts

Uber Geek

#3308296 12-Nov-2024 21:52

AlDrag:

I thought modern outdoor units now a days have "Inverters" and thus can vary their power? So why does it have to run at a fixed output all the time?

they do but only down to 30% or so. however if your system is say sized for the whole house, even at 30% its going to way to much for a small bedroom. i assume the idea is to put in small amount of airflow into the bedroom and dump the rest of the airflow where it doesn't matter so much.

timmmay

20578 posts

Uber Geek

Trusted

Lifetime subscriber

#3308297 12-Nov-2024 21:52

Inverter heat pumps all have minimum and maximum outputs. For example my Daikin is something like 4kw min output, 11kw max output. It would be better if the minimum was more like 1 or 2kw, but the larger heat pumps usually don't ramp down that low.

My small office high wall heat pump in the other hand is something little 500W to 3kw. In winter it often ticks over on minimum power for hours.

The big ducted heat pump is too large most of the time, it turns off and on quite often. Its sized for three bedrooms, our guest room isn't often used but when it is it's a north facing corner room which requires more heating / cooling.

AlDrag

247 posts

Master Geek

#3308302 12-Nov-2024 22:13

timmmay: Inverter heat pumps all have minimum and maximum outputs. For example my Daikin is something like 4kw min output, 11kw max output. It would be better if the minimum was more like 1 or 2kw, but the larger heat pumps usually don't ramp down that low.

My small office high wall heat pump in the other hand is something little 500W to 3kw. In winter it often ticks over on minimum power for hours.

The big ducted heat pump is too large most of the time, it turns off and on quite often. Its sized for three bedrooms, our guest room isn't often used but when it is it's a north facing corner room which requires more heating / cooling.

Right! Great to know!

Ok so this is the one we got quoted on https://www.mitsubishi-electric.co.nz/heatpump/i/69255B/ducted-pead-50-heat-pump
Has a minimum cooling of 2.3kw and 1.7kw heating.

Our existing outdoor unit for downstairs is here https://www.panasonic.com/nz/hvac/air-conditioning/residential/single-room-air-conditioning/aero-xkr-highwall-air-conditioner-v2/cs-cu-z60xkr-1.html
It's 6kw, but if I'm reading it correctly, seems it can go as low as 1.7kw! Despite having more capacity than the Mitsubishi. The Panasonic has way higher Decibel levels for the outdoor unit though.

timmmay

20578 posts

Uber Geek

Trusted

Lifetime subscriber

#3308303 12-Nov-2024 22:30

That's a pretty good minimum. It's a smaller heat pump overall than ours, if it's a smaller house it might be a good fit.

The Panasonic unit we had was a few years ago, they will have changed by now. We could hear the outdoor unit from 10 m away at the other end of our driveway, where is the Daikin we can barely hear from 2 m away outside. The outdoor unit is on the other side of the wall from our lounge, I would place it further away next time, because while it is reasonably quiet when you are watching a quiet scene on TV you can hear it. The Panasonic was significantly louder though.

AlDrag

247 posts

Master Geek

#3308305 12-Nov-2024 22:34

timmmay: That's a pretty good minimum. It's a smaller heat pump overall than ours, if it's a smaller house it might be a good fit.

The Panasonic unit we had was a few years ago, they will have changed by now. We could hear the outdoor unit from 10 m away at the other end of our driveway, where is the Daikin we can barely hear from 2 m away outside. The outdoor unit is on the other side of the wall from our lounge, I would place it further away next time, because while it is reasonably quiet when you are watching a quiet scene on TV you can hear it. The Panasonic was significantly louder though.

So it does seem Panasonic is pretty loud compared to the competition, based on your experience and their own spec sheet haha.

I have no idea if we'd hear ours. They suggested wall mounting the new one above the existing one, and the existing one is outside on the concrete pad right next to our lounge sliding door. I haven't turned it on yet (haven't yet moved in) but the double glazing and insulation really is insanely quiet. But will see if the high pitch whine gets through.

I just realised that they want to wall mount the new unit above the existing one. That would probably create annoying vibrations? Even for a new build. Maybe a stand is better so it's still fixed to the ground? Don't really have the room to mount it next to it, on top is preferable (or I guess the side of the house, but not ideal).

Sorry for all the questions. Just frustrating when these companies don't tell you the compromises etc.

timmmay

20578 posts

Uber Geek

Trusted

Lifetime subscriber

#3308327 13-Nov-2024 07:16

We hear a low pitched rumble. We have double glazing and insulation, but not as good as new. Low frequencies go through walls easier than high it seems.

I was in a house with the heat pump outdoor unit mounted on the wall. When it turned on the whole house vibrated a little, in a way I didn't like. I wouldn't do that personally, even if it means you need to put down another concrete pad.

Companies tell you only what they need to tell you to make the sale. Many probably have no idea of this level of detail as they've never lived with a ducted heat pump. I've also had to concentrate on details to get things working well.

GV27

5896 posts

Uber Geek

#3308341 13-Nov-2024 08:28

I'm in the same boat with this; two level modern four bed duplex with punishingly hot upstairs. Downstairs has a heat-pump (5kw outdoor unit) and master has a smaller unit, two external outdoor units. I have two kids now and their rooms are unbearably hot in summer.

Quoted $5.9K for 2x Mitsubishi units and a small outdoor unit, but that would mean I'm up to three external fans and ideally I'd want to centralise this over time. I probably can't afford to do it upfront.

We already have a ventilation system (positive pressure) so not keen on ducted. There really isn't a great solution either way but I can't do another summer with things the way they are.

1 | 2 | 3 | 4 | 5 | 6 | 7 | ... | 21