Panasonic vs Mitsubishi ducted heat pump and ventilation solutions

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247 posts

Master Geek

#3308367 13-Nov-2024 08:38

GV27:
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.

Why would an existing ventilation system cause you to avoid central ducted?

timmmay

20574 posts

Uber Geek

Trusted

Lifetime subscriber

#3308369 13-Nov-2024 08:43

I guess more ducts might be unslightly for some?

We had / have a positive pressure system. Instead of direct integration we simply have the output of the ventilation system output near the ducted system return grill, so fresh air is effectively but indirectly injected into the system when we turn the ventilation system on.

For anyone with existing ventilation diffusers in rooms you could use the existing diffuser locations for the ducted system, if they're positioned properly for ducted heating / cooling. tbh I never notice the bedroom diffusers, if there were two I wouldn't notice either. You want to avoid having extra holes in the ceiling though, it compromises insulation.

AlDrag

247 posts

Master Geek

#3308404 13-Nov-2024 09:20

Ok I just got some quotes for the Panasonic ducted with EneKan and their basic zone control. Honestly, doesn't seem to be that much cheaper than Mitsubishi despite their initial "claims".

Maybe you guys can help me, here's a floor plan of my top floor with annotations from one of the aircon companies.

I assume I should have intake vents in the opposite diagonal corner of the bedroom doors? Should I also have Lossnay/EneKan returns in the bathrooms?

Now my dilemma is figuring out how to cool/heat that "Office Desk Space" next to the stairs. It's a landing above the stairs with a wall at about 1.5m high. Maybe I should have the return vent at the top of the stairs? Any ideas? I've had 2 different solutions for it from these companies.

Edit: And yes, on the right wall, next to the stairs, that's a big ass window that faces the east.

Ducted floor plan

GV27

5896 posts

Uber Geek

#3308460 13-Nov-2024 11:30

timmmay:

I guess more ducts might be unslightly for some?

We had / have a positive pressure system. Instead of direct integration we simply have the output of the ventilation system output near the ducted system return grill, so fresh air is effectively but indirectly injected into the system when we turn the ventilation system on.

For anyone with existing ventilation diffusers in rooms you could use the existing diffuser locations for the ducted system, if they're positioned properly for ducted heating / cooling. tbh I never notice the bedroom diffusers, if there were two I wouldn't notice either. You want to avoid having extra holes in the ceiling though, it compromises insulation.

Some of the rooms aren't that big and two holes are going to look weird either way.

Also have some anecdata from people we know in Hobsonville with similar townhouses who find the ducted systems just aren't up to it and I won't be able to afford to over-spec it to be sure.

Ultimately I understand the idea of having smaller units on the wall in each room and I know it will work whereas the ducted systems can get pricey with controllers and I can't quite be sure they'll do the job - but we'll still get quotes and install options for each. Money will probably be the deciding factor but whatever I go with has to actually work.

AlDrag

247 posts

Master Geek

#3308510 13-Nov-2024 13:20

And now having second thoughts on putting the new unit above the existing one...maybe it'd be better to have it on the side of the house...but to be fair, not like I'm going to get rid of the existing one.

timbosan

2159 posts

Uber Geek

#3308546 13-Nov-2024 15:30

AlDrag:
tweake:

no, not even close. i highly doubt its air tight, let alone very air tight. if for some reason you think its air tight, get a blower door test done. then you have real numbers to work off. if its very air tight, then range hoods not going to work well and you will need a fix for that. even bath fans may not work properly.

you may simply end up turning the balanced ventilation into a positive pressure system just to account for the lack of air tightness.

simple put nz building relies on the gib for air tightness and no one seals any holes in the gib (houses are not built to be airtight). eg a plumber making a hole oversized to allow for plumbing, that screws the air tightness straight away. with townhouses you can sometimes be tighter because of sheathing, but they do that for bracing and its typically not air sealed. in nz you have to build air tight on purpose, its rare that it will be air tight accidently.

Right. That's good to know. I had no idea. I can't remember where I was getting my information from...

Is a blower door test expensive to do? Maybe it isn't worth getting a ventilation solution like lossnay then?

Doesn't look like you got an answer for this - I cannot give you a price but can tell you that Proclima do blower door tests.

And @tweake is absolutely right (and as I have learnt), unless you are doing something like PassivHaus standards which includes very specific build such as interior vapor barrier which is taped at every join including all electrical and plumbing, you will have drafts :-) If you do contact ProClima they deal in this space and sell the products and can give you more info - I just did lots of research trying to make my 100 year old house less drafty!

AlDrag

247 posts

Master Geek

#3308551 13-Nov-2024 15:44

timbosan:

Doesn't look like you got an answer for this - I cannot give you a price but can tell you that Proclima do blower door tests.

And @tweake is absolutely right (and as I have learnt), unless you are doing something like PassivHaus standards which includes very specific build such as interior vapor barrier which is taped at every join including all electrical and plumbing, you will have drafts :-) If you do contact ProClima they deal in this space and sell the products and can give you more info - I just did lots of research trying to make my 100 year old house less drafty!

Thanks, I might query! Although I imagine it doesn't really matter that much? Why does the "draftiness" of a home matter that much when it comes to ventilation? I imagine some rooms will still fill up with C02 regardless. For example, we used to sleep with our bedroom door closed in a 1970s home (I think floor and ceiling is insulated) and it used to get so miserable in there when we woke up. Air was so stale, even in winter (and no heater).

Not being condescending, just trying to learn :)

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SnoopyDo

18 posts

Geek

#3308560 13-Nov-2024 15:56

Do some digging on the Lossney, I believe the installer can set an offset in the supply and exhaust air fan speeds to provide a slightly positive pressure system to provide for our leaky homes.

Kickinbac

427 posts

Ultimate Geek

#3308569 13-Nov-2024 16:09

AlDrag:

timbosan:

Doesn't look like you got an answer for this - I cannot give you a price but can tell you that Proclima do blower door tests.

And @tweake is absolutely right (and as I have learnt), unless you are doing something like PassivHaus standards which includes very specific build such as interior vapor barrier which is taped at every join including all electrical and plumbing, you will have drafts :-) If you do contact ProClima they deal in this space and sell the products and can give you more info - I just did lots of research trying to make my 100 year old house less drafty!

Thanks, I might query! Although I imagine it doesn't really matter that much? Why does the "draftiness" of a home matter that much when it comes to ventilation? I imagine some rooms will still fill up with C02 regardless. For example, we used to sleep with our bedroom door closed in a 1970s home (I think floor and ceiling is insulated) and it used to get so miserable in there when we woke up. Air was so stale, even in winter (and no heater).

Not being condescending, just trying to learn :)

I have a different opinion to Tweake, from another post he is very adamant and vehemently against MVHR, yet the current building science says MVHR is the best solution, even in houses not built to passivhaus standards.

I think MVHR (balanced pressure ventilation with heat recovery) is definitely the way to go if you can afford it. Basically looking for a continuous air change rate of about 0.5 AC/Hr. This helps with reducing CO2 levels and moisture. It enables the system to rub 24/7, no need to open windows etc if there are noise, security or weather issues. There are many types of MVHR, such as the super expressive Zhender systems that are passvihaus certified but then there are many other systems for more conventional houses such as Lossnay systems.

MVHR means you are in control of the ventilation rate and filtration in your home rather than relying on opening windows to what ever the weather conditions are at the time. Thsnk of a still day vs a rainy day. The heat recovery element of the system means that you keep most of the energy you paid for heating or cooling your home.

A positive pressure system has some ventilation benefits but you are pushing out all the heating or cooling you've paid for. That seems dumb to me.

I have a Lossnay in my home and highly recommend it. I had this in my last home too.

AlDrag

247 posts

Master Geek

#3308590 13-Nov-2024 16:32

Kickinbac:

I have a different opinion to Tweake, from another post he is very adamant and vehemently against MVHR, yet the current building science says MVHR is the best solution, even in houses not built to passivhaus standards.

I think MVHR (balanced pressure ventilation with heat recovery) is definitely the way to go if you can afford it. Basically looking for a continuous air change rate of about 0.5 AC/Hr. This helps with reducing CO2 levels and moisture. It enables the system to rub 24/7, no need to open windows etc if there are noise, security or weather issues. There are many types of MVHR, such as the super expressive Zhender systems that are passvihaus certified but then there are many other systems for more conventional houses such as Lossnay systems.

MVHR means you are in control of the ventilation rate and filtration in your home rather than relying on opening windows to what ever the weather conditions are at the time. Thsnk of a still day vs a rainy day. The heat recovery element of the system means that you keep most of the energy you paid for heating or cooling your home.

A positive pressure system has some ventilation benefits but you are pushing out all the heating or cooling you've paid for. That seems dumb to me.

I have a Lossnay in my home and highly recommend it. I had this in my last home too.

This is the kind of stuff I was reading online (can't remember where). Opening windows is fine, but in new builds they only open a tiny bit and there's no good pathway to create a proper pathway breeze. Might be good enough though, but regardless, it's wasted energy.

Being able to sleep in our room (and our toddler sleep in theirs) with fresh air all night will aircon is running is the stuff of dreams that I can't wait to have.

Based on this, will definitely get Lossnay. I've been quoted for only like an extra 2.5k for it anyway.

Edit: Your explanation also helps me understand why position pressure ventilation isn't ideal.

Kickinbac

427 posts

Ultimate Geek

#3308593 13-Nov-2024 16:34

AlDrag:

Ok I just got some quotes for the Panasonic ducted with EneKan and their basic zone control. Honestly, doesn't seem to be that much cheaper than Mitsubishi despite their initial "claims".

Maybe you guys can help me, here's a floor plan of my top floor with annotations from one of the aircon companies.

I assume I should have intake vents in the opposite diagonal corner of the bedroom doors? Should I also have Lossnay/EneKan returns in the bathrooms?

Now my dilemma is figuring out how to cool/heat that "Office Desk Space" next to the stairs. It's a landing above the stairs with a wall at about 1.5m high. Maybe I should have the return vent at the top of the stairs? Any ideas? I've had 2 different solutions for it from these companies.

Edit: And yes, on the right wall, next to the stairs, that's a big ass window that faces the east.

What you've got here is a system that recirculating all the air in that area. So what is supplied to the bedrooms returns to the grille in the hallway. It's important doors are left open, undercut or have door grilles to allow the conditioned air to circulate unimpeded. Another option is to have a return grille in each room if you want the doors closed. The room temperature is controlled by a temperature sensor in the return air duct or at the wall controller, basically averaging the whole space. The office desk space is essentially part of this space but also significantly affected by what is happening downstairs and the heat rising to the upper floor. I'd probably add a diffuser over the stairwell to get the best airflow. You need to think of it as a whole house solution.

I've seen many installation problems with ducted system installations that cause problems with efficiency, split ducts, leaky plenums, poor workmanship etc. You need to be confident you are getting a good quality install which is sometimes hard to determine.

Plus remember that the ducting is installed in the super hot or super cold roof space, outside of the insulated thermal envelope of your home. Insulated flexible duct has an R rating of R1.0 and your ceiling insulation is going to be minimum R3.6. The energy efficiency rating of a ducted system takes no account of the supply and return ducting and air leakage. A hi-wall energy efficiency is what it is as it's inside the thermal envelope.

I'm in the hi-wall camp, you can't beat a small hi-wall for being super energy efficient and good temperature control. I'm also more about energy efficiency and good temperature control over how it looks!

However, in your home, a neat and tidy install of hi-walls is going to be tricky with lots of capping etc. The main problem will be the condensate drains from the indoor units. You don't really want condensate pumps installed on bedroom units as the noise can be annoying.

Edit - in this case I think the ducted system will be the better all round solution. All air conditioning systems have a compromise!

AlDrag

247 posts

Master Geek

#3308645 13-Nov-2024 16:43

Kickinbac:

What you've got here is a system that recirculating all the air in that area. So what is supplied to the bedrooms returns to the grille in the hallway. It's important doors are left open, undercut or have door grilles to allow the conditioned air to circulate unimpeded. Another option is to have a return grille in each room if you want the doors closed. The room temperature is controlled by a temperature sensor in the return air duct or at the wall controller, basically averaging the whole space. The office desk space is essentially part of this space but also significantly affected by what is happening downstairs and the heat rising to the upper floor. I'd probably add a diffuser over the stairwell to get the best airflow. You need to think of it as a whole house solution.

I've seen many installation problems with ducted system installations that cause problems with efficiency, split ducts, leaky plenums, poor workmanship etc. You need to be confident you are getting a good quality install which is sometimes hard to determine.

Plus remember that the ducting is installed in the super hot or super cold roof space, outside of the insulated thermal envelope of your home. Insulated flexible duct has an R rating of R1.0 and your ceiling insulation is going to be minimum R3.6. The energy efficiency rating of a ducted system takes no account of the supply and return ducting and air leakage. A hi-wall energy efficiency is what it is as it's inside the thermal envelope.

I'm in the hi-wall camp, you can't beat a small hi-wall for being super energy efficient and good temperature control. I'm also more about energy efficiency and good temperature control over how it looks!

However, in your home, a neat and tidy install of hi-walls is going to be tricky with lots of capping etc. The main problem will be the condensate drains from the indoor units. You don't really want condensate pumps installed on bedroom units as the noise can be annoying.

That's the scary thing. The 2 guys I had come in seem like they know their stuff, but you never really know until they do it. They probably just want to get it done as fast as possible, but I'm going to try be involved. Avoid them making sharp 90 degree turns, make sure they raise the unit off the ceiling floor etc.

Annoyingly, every company I contacted, they use R0.6 by default! Without even telling me in the quote, but I've asked for R1.0 which they luckily provide. My Dad, who works on commerical aircon ducting, said that R1.5 miminum is basically standard in Aussie. But he's in a bit of a bubble due to doing commercial (and I guess Aussie gets a lot hotter).

When I asked one of the guys about multi-split options, he did state I'd need a pump...so would like to avoid that.

Here's a photo of our ceiling space. I didn't take the photo myself, but no idea if the top part is insulated. I assume not...

Edit: I guess I could just wrap all the ducting in super cheap insulation blankets myself post-install...

timbosan

2159 posts

Uber Geek

#3308725 13-Nov-2024 17:53

Kickinbac:

AlDrag:

Thanks, I might query! Although I imagine it doesn't really matter that much? Why does the "draftiness" of a home matter that much when it comes to ventilation? I imagine some rooms will still fill up with C02 regardless. For example, we used to sleep with our bedroom door closed in a 1970s home (I think floor and ceiling is insulated) and it used to get so miserable in there when we woke up. Air was so stale, even in winter (and no heater).

Not being condescending, just trying to learn :)

I have a different opinion to Tweake, from another post he is very adamant and vehemently against MVHR, yet the current building science says MVHR is the best solution, even in houses not built to passivhaus standards.

I think MVHR (balanced pressure ventilation with heat recovery) is definitely the way to go if you can afford it. Basically looking for a continuous air change rate of about 0.5 AC/Hr. This helps with reducing CO2 levels and moisture. It enables the system to rub 24/7, no need to open windows etc if there are noise, security or weather issues. There are many types of MVHR, such as the super expressive Zhender systems that are passvihaus certified but then there are many other systems for more conventional houses such as Lossnay systems.

MVHR means you are in control of the ventilation rate and filtration in your home rather than relying on opening windows to what ever the weather conditions are at the time. Thsnk of a still day vs a rainy day. The heat recovery element of the system means that you keep most of the energy you paid for heating or cooling your home.

A positive pressure system has some ventilation benefits but you are pushing out all the heating or cooling you've paid for. That seems dumb to me.

I have a Lossnay in my home and highly recommend it. I had this in my last home too.

Might be semantics but I thought Zhender are mechanical ventilation (as in the MVHR designation you used) whereas Lossnay wasn't? Happy to be corrected!

BTW thanks for answering the question - and good note on "opening windows" - this is not a good idea if your aim to control moisture, pollutants, temperature, etc.

tweake

2391 posts

Uber Geek

#3308732 13-Nov-2024 18:11

AlDrag:

This is the kind of stuff I was reading online (can't remember where). Opening windows is fine, but in new builds they only open a tiny bit and there's no good pathway to create a proper pathway breeze. Might be good enough though, but regardless, it's wasted energy.

Being able to sleep in our room (and our toddler sleep in theirs) with fresh air all night will aircon is running is the stuff of dreams that I can't wait to have.

Based on this, will definitely get Lossnay. I've been quoted for only like an extra 2.5k for it anyway.

Edit: Your explanation also helps me understand why position pressure ventilation isn't ideal.

its not that positive pressure isn't ideal, its that the house are not good enough to be worth using better. (i'm not sure on how old your house is but nz insulation only caught up to bare minimum in the last few years.)

the problem with natural ventilation aka air leakage is its weather dependent. doesn't matter if the windows are open, no wind = no ventilation. but also lots of wind = lots of ventilation, at times way to much ventilation.

with a good air tight tight house (eg passive house) you have to have balanced ventilation, positive pressure won't work. if its a bit more air leaky balanced works ok but its returns is reduced because air leakage brings in pollen, dirt, humidity, cold, etc. when the wind blows the worse it gets. the more leakage the less effect the system has, the less gains, the less heat recovered. then with a normal nz built house its going to be leaking as much air as your ventilating with. so your gains/recovery really start to disappear and are non-existent when the wind blows.

add to that positive pressure is cheaper and simpler, plus it can use some of the air leakage inlet as an outlet.

so in nz typical air leaky homes, positive pressure does the job for less. most of the claims about balanced systems is salesman talk because the amount of air tight homes is tiny. they are selling erv's and not telling people that they keep moisture in (mold anyone?).

this is why i say blower door test, then you know whats worth doing.

tweake

2391 posts

Uber Geek

#3308735 13-Nov-2024 18:13

AlDrag:

Thanks, I might query! Although I imagine it doesn't really matter that much? Why does the "draftiness" of a home matter that much when it comes to ventilation? I imagine some rooms will still fill up with C02 regardless. For example, we used to sleep with our bedroom door closed in a 1970s home (I think floor and ceiling is insulated) and it used to get so miserable in there when we woke up. Air was so stale, even in winter (and no heater).

Not being condescending, just trying to learn :)

probably not stale air. odds are it was air/moisture etc thats come up through the floor (assuming wooden floor).

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