Panasonic vs Mitsubishi ducted heat pump and ventilation solutions

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

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2391 posts

Uber Geek

#3309394 15-Nov-2024 15:11

AlDrag:

Yea I read about putting Lossnay inlets into the bathroom as an extractor as a great idea to reduce condensation and return heat, but I guess the existing extractor fans for the bathrooms can serve that purpose (although you lose heat).

Hmmmmm I think Lossnay only works through the ducted system...I could be wrong though, but I think I heard it's always running.

i kinda cringe at that statement. if your house is airtight those extractor fans won't be doing a whole lot. using the lossnay as the extractor fans is a good thing.

the lossnay should be wired to the heat pump. it tells the heat pump fan to run at low speed constantly. your using the heat pump to circulate the air through out the house/floor to distribute the ventilation air. make sure they wire it and program it, not just tell you to keep the heat pump running.

one issue is the stairwell. hot air from bellow will come up and cool air will fall (one reason why a downstairs vent would be best) so the heat pump needs to be sized enough to handle that bit extra. also if you do use a spill zone use the office desk/stair well area.

don't forget to install humidity gauges as well, especially upstairs.

AlDrag

247 posts

Master Geek

#3309398 15-Nov-2024 15:26

tweake:

i kinda cringe at that statement. if your house is airtight those extractor fans won't be doing a whole lot. using the lossnay as the extractor fans is a good thing.

the lossnay should be wired to the heat pump. it tells the heat pump fan to run at low speed constantly. your using the heat pump to circulate the air through out the house/floor to distribute the ventilation air. make sure they wire it and program it, not just tell you to keep the heat pump running.

one issue is the stairwell. hot air from bellow will come up and cool air will fall (one reason why a downstairs vent would be best) so the heat pump needs to be sized enough to handle that bit extra. also if you do use a spill zone use the office desk/stair well area.

don't forget to install humidity gauges as well, especially upstairs.

Why the cringe? I guess the house isn't that airtight then? Because it can't be if it has extraction fans right? As those vents have to go somewhere and they won't be some fancy electronic shutter ones or something. Just always open to the outside with a fan probably?
So should I get them to replace the existing exhaust fans with Lossnay exhaust? I guess the attic space will still have the open outtakes from the existing extraction fans.

Right. That seems to land in what I've read about Lossnay.

Yea that stairwell frustrates me....so worried that whatever we do, it won't work because of it. I'll enquire if we need to increase the size of the heatpump, but then it'll mean it can't run at a lower power for a single or 2 rooms...ugh.

I assume humidity gauges come with Lossnay, otherwise I assume I can retrofit my own and control with home assistant....but maybe not.

tweake

2391 posts

Uber Geek

#3309404 15-Nov-2024 16:01

AlDrag:

Why the cringe? I guess the house isn't that airtight then? Because it can't be if it has extraction fans right? As those vents have to go somewhere and they won't be some fancy electronic shutter ones or something. Just always open to the outside with a fan probably?
So should I get them to replace the existing exhaust fans with Lossnay exhaust? I guess the attic space will still have the open outtakes from the existing extraction fans.

Right. That seems to land in what I've read about Lossnay.

Yea that stairwell frustrates me....so worried that whatever we do, it won't work because of it. I'll enquire if we need to increase the size of the heatpump, but then it'll mean it can't run at a lower power for a single or 2 rooms...ugh.

I assume humidity gauges come with Lossnay, otherwise I assume I can retrofit my own and control with home assistant....but maybe not.

its just if the house is air tight then the bath fans and kitchen fan won't doing much. if its not air airtight there not a lot of reason to have the erv. its trying to mix two very different things that grinds my gears a tad. like people spending a ton of money on a passive house, only to open up all the doors and windows and render it all pointless.

anyway, the stairwell it depends on if they have accounted for that and that there is the downstairs heat pump running as well. this will also come down to how you run the system. you really have to run both at the same time. where in whole house heating era, not heating by rooms as we traditionally did. upstairs heat pump will have to favor cooling, while down stairs will favor heating (check the output specs).

no gauges come with the lossnay, just the control pad. most erv systems are paired with dehumidifiers. if your going to do without one, its critical you keep an eye on the humidity so you don't turn the house into a mold factory.. the sales person should have told you this.

timmmay

20574 posts

Uber Geek

Trusted

Lifetime subscriber

#3309451 15-Nov-2024 19:29

AlDrag:

Oh and this is the default outlet they use https://smooth-air.co.nz/pycd200

Those are the first diffusers I had, and the worst ones overall. They're ok in some circumstances, like bedrooms where the air is drawn across the room and down out a duct or similar, but they're awful if the diffuser is in the same area as the return. In that case the air just goes across the ceiling and causes heat stratification - ceiling is warm, floor is cold.

My second type of diffusers were these. Better in theory, in practice no different.

The ones I have now are some variant of this these square MDO diffusers. Smooth Air NZ used to sell them, but I can't see them there now. They let you direct the air where you want it to go - straight down, all in one direction, everywhere, etc. It's super handy to be able to change this. It's nice in winter to have a warm breeze blow across you, but it's less nice in summer to have a really cold breeze so I make it indirect. My wife doesn't like cool air blowing across her in summer, so I direct the air other ways, in winter the warm air goes all over. I wouldn't have a ducted system without diffusers like these, or some others that perform a similar function.

R1.0 ducting is the best I could find in NZ, it was a small cost to upgrade to. Someone said in aus they have thicker, but their ceiling cavities probably get way, way hotter than ours. I wonder if they have ducting inside the insulated envelope in new builds... I'll ask a mate who just built a house there.

Suggest you see if you can find someone with the Lossnay in the bathroom to give their opinion. I once read as an extractor it's good because it captures the heat from shower steam without keeping the moisture, but I wonder how high volume it is... we have a very high volume fan in our bathroom, two speeds. We crack open the window for air, and often also run the positive pressure system so that provides air to the house. Our old house isn't near airtight so probably doesn't matter, but I don't want ceiling cavity or under floor air drawn into the house.

AlDrag

247 posts

Master Geek

#3309452 15-Nov-2024 19:46

Ugh it's frustrating, I feel like I'm getting a lack of information from both companies I've enquired with and getting mixed reports from users. e.g. tweake stating that Lossnay is pointless for a non-passive house (and sounds like most new builds in NZ aren't passive) but some people are super happy with their lossnay in 90 year old homes...I have no idea...
Like how does it work? In a bedroom, no fresh air would be getting in if the aircon was on right? Because it would be positive pressurising the room. However I guess the extractor outlet would bring in fresh air from gaps in the house maybe? and thus that would get into the room?
Please educate me haha. I want to understand.

In regards to the diffuser options, I love those square ones, and the site I linked has them. Awesome that you can adjust the direction. I'll get them.

Good idea in regards to the bathroom vents. When I asked the company if it was a good idea, they just said they can do it, not if it was a good idea lol. I just need an actual "expert" to tell me what the hell is the best solution without trying to sell me a gimped Panasonic system without zoning....

tweake

2391 posts

Uber Geek

#3309455 15-Nov-2024 19:58

diffuses, i have used plastic-swirl-diffuser but i'm thumping them with a big freakin fan at much higher pressure and air speeds than hvac. they do about a 40 degree down angle, induce a lot of swirl and mix quite well.

tweake

2391 posts

Uber Geek

#3309457 15-Nov-2024 20:14

AlDrag:

Ugh it's frustrating, I feel like I'm getting a lack of information from both companies I've enquired with and getting mixed reports from users. e.g. tweake stating that Lossnay is pointless for a non-passive house (and sounds like most new builds in NZ aren't passive) but some people are super happy with their lossnay in 90 year old homes...I have no idea...
Like how does it work? In a bedroom, no fresh air would be getting in if the aircon was on right? Because it would be positive pressurising the room. However I guess the extractor outlet would bring in fresh air from gaps in the house maybe? and thus that would get into the room?
Please educate me haha. I want to understand.

some clarification i hope. its not pointless for a non passive house, just pointless for an air leaky house where you don't really get the gain for the extra cost. you can get fairly air tight homes that are not passive house levels where they will work ok. thats why i made the point of blower door testing the house. that way you know what good its going to do, or not do.

loosney in a 90 year old home, thats more about salesmanship. its placebo effect. they buy a gadget that they are told it fixes everything, and because they spend lots of money, of course it works. it always works perfectly even tho they havn't tested it. they get sold a dream not reality.

so with loosney + ducted heat pump they work hand in hand. the lossney is always on and it tells the heat pump fan to turn on at low speed. so it pumps fresh air to rooms, which then exits (typically under cut door or other outlet) and into the hallway. some will circulate back through the heat pump return while the rest exhausts out the loosney vents in the bath rooms (and house leakage).

if aircon/heat turns on, the fan ramps up and pushes more air through the rooms and back to the heat pump return. the ventilation air remains unchanged, its still being pumped through with the heat pump airflow.

i hope that helps.

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Kickinbac

427 posts

Ultimate Geek

#3309496 15-Nov-2024 22:53

I say, don’t over think it, get on and do it. You have a new house, double glazing, good insulation so it should be built well and energy efficient. It will be as airtight as any modern standard house construction and you can’t do too much to change that, so just accept it.

A ducted system to air condition the whole of upstairs, the existing hi-wall to condition downstairs. Play around with the settings until you find what suits. It will heat and cool your house well. The Lossnay will ventilate the house getting rid of moisture and CO2 and is designed to work with the ducted unit controls. Mitsubishi Electric is good equipment and well supported in NZ.

There are different models of Lossnay systems, ERV and HRV. ERV have a heat exchanger core that is moisture permeable, basically meaning the sensible and latent heat is recovered and these are not recommended for wet area extraction.
The HRV version only recovers the sensible heat so a little less efficient but neither here nor there, only a few percent less efficient.
Most of the current Lossnay models are now HRV and suitable for wet areas. Would be good to know what model they are quoting for.

Just so you know I’m not some internet warrior. I’m an HVAC engineer, 26 years experience, I do design, project management, am IQP, producer statement author, Member of IRHACE etc so hopefully know what I’m doing by now. I mainly do commercial and industrial work, some but not a lot of residential work. They are similar in theory but also quite different beasts in application! .

I have a Lossnay ERV commercial version in my house and haven’t seen or noticed any issues with moisture. I got my Lossnay fairly cheap (second via BDT) and put it in myself. I’ve kinda done a retrofit experiment in my house to test out some theories and products. It’s hard to retrofit into an existing 2 story house! It functions.
We use hi-walls for heating and cooling, I pay the power bill so I like the COP close to 5!
My MVHR is designed and commissioned for 0.5 AC/hr being 39 L/s for the whole house. It extracts about 10 L/s from each of the 2 bathrooms. I’ve kept the extractor fans with backdraft dampers in the bathrooms and we use them just when showering. I consider this the boost mode to get rid of most of the moisture at source. Overall the house is fresher and no condensation. It’s an 80’s house and has single glazing which is on the list to be upgraded as funds allow.
I turn the MVHR off when we open up the house but in winter it’s running continuously. We run it in summer, it has a heat exchanger bypass to supply cool outside air. Keeps the house ventilated when we are not home. I’m happy with the result. It’s not perfect but I can’t afford that! lol.

Tweake mentioned previously to add extra insulation in your roof, I second that, an additional blanket over top of the existing insulation when installed well will save you energy.

Picture of my Lossnay installed in my downstairs garage.

AlDrag

247 posts

Master Geek

#3309500 15-Nov-2024 23:21

Kickinbac: I say, don’t over think it, get on and do it. You have a new house, double glazing, good insulation so it should be built well and energy efficient. It will be as airtight as any modern standard house construction and you can’t do too much to change that, so just accept it.

There are different models of Lossnay systems, ERV and HRV. ERV have a heat exchanger core that is moisture permeable, basically meaning the sensible and latent heat is recovered and these are not recommended for wet area extraction.
The HRV version only recovers the sensible heat so a little less efficient but neither here nor there, only a few percent less efficient.
Most of the current Lossnay models are now HRV and suitable for wet areas. Would be good to know what model they are quoting for.

Just so you know I’m not some internet warrior. I’m an HVAC engineer, 26 years experience, I do design, project management, am IQP, producer statement author, Member of IRHACE etc so hopefully know what I’m doing by now. I mainly do commercial and industrial work, some but not a lot of residential work. They are similar in theory but also quite different beasts in application! .

I have a Lossnay ERV commercial version in my house and haven’t seen or noticed any issues with moisture. I got my Lossnay fairly cheap (second via BDT) and put it in myself. I’ve kinda done a retrofit experiment in my house to test out some theories and products. It’s hard to retrofit into an existing 2 story house! It functions.
We use hi-walls for heating and cooling, I pay the power bill so I like the COP close to 5!
My MVHR is designed and commissioned for 0.5 AC/hr being 39 L/s for the whole house. It extracts about 10 L/s from each of the 2 bathrooms. I’ve kept the extractor fans with backdraft dampers in the bathrooms and we use them just when showering. I consider this the boost mode to get rid of most of the moisture at source. Overall the house is fresher and no condensation. It’s an 80’s house and has single glazing which is on the list to be upgraded as funds allow.
I turn the MVHR off when we open up the house but in winter it’s running continuously. We run it in summer, it has a heat exchanger bypass to supply cool outside air. Keeps the house ventilated when we are not home. I’m happy with the result. It’s not perfect but I can’t afford that! lol.

Tweake mentioned previously to add extra insulation in your roof, I second that, an additional blanket over top of the existing insulation when installed well will save you energy.

Picture of my Lossnay installed in my downstairs garage.

I've been quoted for Lossnay VL-220, which seems to be an HRV system based on the brochure, so I should be sweet. Looks like return vents (to remove stale air) for the Lossnay should just be in bathrooms? (in my case, since I'm just handling upstairs, which is just a hallway, bathrooms and bedrooms).

A COP of close to 5 would be amazing! So understand why you went that route.
I've been quoted with the Mitsubishi Electric PEAD-M50JAA which has a COP of 4.16, which seems pretty good and definitely better than the competition at 6kw cooling (7kw heating).
I am little unsure if I need to go up to the slightly bigger model of 7kw cooling (8kw heating). I hope not, as that has a COP of 3.78. Funnily enough, the slightly bigger model above that has a COP of 4.0.

Looks like for this Lossnay the model, based on the brochure, the heat exchanger bypass might be optional. I'll enquire with the installation company about that.

I like the idea of adding extra insulation to my roof like Tweake mentioned, but I think he mentioned adding it to the top part of the roof? Not the ceiling? Not sure that can be easily done and not even sure if there is insulation there (not sure if it's possible to tell in the photo I posted). I will have to check it out when I actually settle into the house.

Really appreciate hearing your expertise. Exactly what I wanted. Everyone else has been amazing help also.

Kickinbac

427 posts

Ultimate Geek

#3309504 15-Nov-2024 23:55

AlDrag:
Kickinbac: I say, don’t over think it, get on and do it. You have a new house, double glazing, good insulation so it should be built well and energy efficient. It will be as airtight as any modern standard house construction and you can’t do too much to change that, so just accept it.

There are different models of Lossnay systems, ERV and HRV. ERV have a heat exchanger core that is moisture permeable, basically meaning the sensible and latent heat is recovered and these are not recommended for wet area extraction.
The HRV version only recovers the sensible heat so a little less efficient but neither here nor there, only a few percent less efficient.
Most of the current Lossnay models are now HRV and suitable for wet areas. Would be good to know what model they are quoting for.

Just so you know I’m not some internet warrior. I’m an HVAC engineer, 26 years experience, I do design, project management, am IQP, producer statement author, Member of IRHACE etc so hopefully know what I’m doing by now. I mainly do commercial and industrial work, some but not a lot of residential work. They are similar in theory but also quite different beasts in application! .

I have a Lossnay ERV commercial version in my house and haven’t seen or noticed any issues with moisture. I got my Lossnay fairly cheap (second via BDT) and put it in myself. I’ve kinda done a retrofit experiment in my house to test out some theories and products. It’s hard to retrofit into an existing 2 story house! It functions.
We use hi-walls for heating and cooling, I pay the power bill so I like the COP close to 5!
My MVHR is designed and commissioned for 0.5 AC/hr being 39 L/s for the whole house. It extracts about 10 L/s from each of the 2 bathrooms. I’ve kept the extractor fans with backdraft dampers in the bathrooms and we use them just when showering. I consider this the boost mode to get rid of most of the moisture at source. Overall the house is fresher and no condensation. It’s an 80’s house and has single glazing which is on the list to be upgraded as funds allow.
I turn the MVHR off when we open up the house but in winter it’s running continuously. We run it in summer, it has a heat exchanger bypass to supply cool outside air. Keeps the house ventilated when we are not home. I’m happy with the result. It’s not perfect but I can’t afford that! lol.

Tweake mentioned previously to add extra insulation in your roof, I second that, an additional blanket over top of the existing insulation when installed well will save you energy.

Picture of my Lossnay installed in my downstairs garage.

I've been quoted for Lossnay VL-220, which seems to be an HRV system based on the brochure, so I should be sweet. Looks like return vents (to remove stale air) for the Lossnay should just be in bathrooms? (in my case, since I'm just handling upstairs, which is just a hallway, bathrooms and bedrooms).

A COP of close to 5 would be amazing! So understand why you went that route.
I've been quoted with the Mitsubishi Electric PEAD-M50JAA which has a COP of 4.16, which seems pretty good and definitely better than the competition at 6kw cooling (7kw heating).
I am little unsure if I need to go up to the slightly bigger model of 7kw cooling (8kw heating). I hope not, as that has a COP of 3.78. Funnily enough, the slightly bigger model above that has a COP of 4.0.

Looks like for this Lossnay the model, based on the brochure, the heat exchanger bypass might be optional. I'll enquire with the installation company about that.

I like the idea of adding extra insulation to my roof like Tweake mentioned, but I think he mentioned adding it to the top part of the roof? Not the ceiling? Not sure that can be easily done and not even sure if there is insulation there (not sure if it's possible to tell in the photo I posted). I will have to check it out when I actually settle into the house.

Really appreciate hearing your expertise. Exactly what I wanted. Everyone else has been amazing help also.

What’s the floor area and what size is the heat pump downstairs? In your plan posted earlier I can’t see all the dimensions. I can do some quick numbers on capacity.

The VL-220 is good and designed for exhausting from wet areas. You could add the bypass but you are doing ducted AC so do have cooling. It depends on the additional cost of the bypass kit, I reckon it’s around $300 + gst so might be better to just spend that on electricity.

Insulation goes on top of the existing as a top up. It’s not really practical to add at roof level now, too many problems with the installation, cost and creating a building consent issue.
That’s the main problem with ducted AC in the roof, it’s outside the thermal envelope,so it’s essentially outside plus the heat of the roof space in summer. It can be 50 degrees in the roof space.

AlDrag

247 posts

Master Geek

#3309505 16-Nov-2024 00:27

Kickinbac:

What’s the floor area and what size is the heat pump downstairs? In your plan posted earlier I can’t see all the dimensions. I can do some quick numbers on capacity.

The VL-220 is good and designed for exhausting from wet areas. You could add the bypass but you are doing ducted AC so do have cooling. It depends on the additional cost of the bypass kit, I reckon it’s around $300 + gst so might be better to just spend that on electricity.

Insulation goes on top of the existing as a top up. It’s not really practical to add at roof level now, too many problems with the installation, cost and creating a building consent issue.
That’s the main problem with ducted AC in the roof, it’s outside the thermal envelope,so it’s essentially outside plus the heat of the roof space in summer. It can be 50 degrees in the roof space.

Floor area I'm not really sure...but from the external cladding, the house is 150m2 (this is the size they use for insurance. Annoyingly, fletchers doesn't provide a floor area). The ceiling height is 2.55m.

Here's my floor plan. As you can see, I have stated that I have an existing Panasonic 6kw (cooling)/7.2kw (heating) split in the open living area. That should cover the entire area (I hope).

Upstairs I have that open landing where my study/office area will be with a desk that I'd like to be a decent temp. There is a big window on the east side above the stairs that could take in a lot of morning heat from the sun, but will obviously have blinds of some sort.
The tricky part is that stupid landing/stairs space. That's the reason I'm worried I need a bigger unit, but hoping not.

The fact that fletchers didn't insulate the roof space is a big downer....I assume ducting will be way less efficient due to that, even with the R1.0 ducts...

Ground Upper Floor

tweake

2391 posts

Uber Geek

#3309521 16-Nov-2024 09:21

Kickinbac:

There are different models of Lossnay systems, ERV and HRV. ERV have a heat exchanger core that is moisture permeable, basically meaning the sensible and latent heat is recovered and these are not recommended for wet area extraction.

total nonsense. ERV are used for wet area extraction all the time, its pretty much the standard in passive house.

in seriously air tight homes, you can't use bath fans because you exhaust more air than what leaks back into the house. you have to balance the airflows. the same with range hoods where you use make up air (which is common in industrial).

the problem is sales people BS their customers. ERV's really need to be paired with dehumidifiers. ERV keeps outdoor humidity out (which an HRV doesn't do) and the dehumidifier makes sure the indoors humidity stays at a good amount. if your Auckland north then outdoor humidity is the biggest source of humidity in the home. i dry clothes inside a lot and indoor humidity never changes, but if weather changes the indoor humidity skyrockets, the downside of air leaky homes. if your down south where the outdoor humidity is pretty decent most of the time, then HRV will be fine.

tweake

2391 posts

Uber Geek

#3309524 16-Nov-2024 09:31

Kickinbac: I say, don’t over think it, get on and do it. You have a new house, double glazing, good insulation so it should be built well and energy efficient. It will be as airtight as any modern standard house construction and you can’t do too much to change that, so just accept it.

Just so you know I’m not some internet warrior. I’m an HVAC engineer,

but this is NZ low standard of construction. its not good insulation (as the ceiling insulation shows) and as its bare minimum standard, its not what i would call efficient. keep in mind they only went UP to bare minimum with this new standard recently, thats how bad nz housing is. they also claimed they where "over insulated" (which branz debunked) which shows just how bad the industry is.

this is why "i'm a professional" means absolutely nothing. theres quite a few examples in here of professionals getting it wrong. they are usually more interested in selling you a gadget than making a system work properly.

tweake

2391 posts

Uber Geek

#3309525 16-Nov-2024 09:40

Kickinbac:
AlDrag:

I like the idea of adding extra insulation to my roof like Tweake mentioned, but I think he mentioned adding it to the top part of the roof? Not the ceiling?

Insulation goes on top of the existing as a top up. It’s not really practical to add at roof level now, too many problems with the installation, cost and creating a building consent issue.
That’s the main problem with ducted AC in the roof, it’s outside the thermal envelope,so it’s essentially outside plus the heat of the roof space in summer. It can be 50 degrees in the roof space.

correct.

as above i was refer to just adding to the existing insulation. in fact you can get insulation in blanket form which reduces the amount of segments and air gaps in the insulation.

converting to a hot roof design is major task. hot roofs are becoming a more common trend and its something people should be asking for because it turns the ceiling space into a conditioned space (ie normal room) which is ideal for storage and heat pump installation.

Kickinbac

427 posts

Ultimate Geek

#3309528 16-Nov-2024 09:48

tweake:
AlDrag:

Yea I read about putting Lossnay inlets into the bathroom as an extractor as a great idea to reduce condensation and return heat, but I guess the existing extractor fans for the bathrooms can serve that purpose (although you lose heat).

Hmmmmm I think Lossnay only works through the ducted system...I could be wrong though, but I think I heard it's always running.

i kinda cringe at that statement. if your house is airtight those extractor fans won't be doing a whole lot. using the lossnay as the extractor fans is a good thing.

the lossnay should be wired to the heat pump. it tells the heat pump fan to run at low speed constantly. your using the heat pump to circulate the air through out the house/floor to distribute the ventilation air. make sure they wire it and program it, not just tell you to keep the heat pump running.

one issue is the stairwell. hot air from bellow will come up and cool air will fall (one reason why a downstairs vent would be best) so the heat pump needs to be sized enough to handle that bit extra. also if you do use a spill zone use the office desk/stair well area.

don't forget to install humidity gauges as well, especially upstairs.

I should have said BDT don’t recommend their Lossnay ERV for extraction from wet areas. I don’t why they say this but I suspect that they have had an issue with their paper core heat exchangers. I haven’t got to anyone at BDT that can give me a good explanation.
I have paper core Lossnay in my house and have taken out the core a couple of times and can’t see any issues. I put a paper core Lossnay in my parents house about 12 years ago and it’s fine, it’s the only one I’ve been able to monitor long term.

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