Balanced ventilation with heat recovery

Forums › Home Workshop DIY › Balanced ventilation with heat recovery

1 | 2 | 3 | 4

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#2709057 18-May-2021 15:50

Hi - I have requested this thread to be unlocked in the hope some of you here that had Zehnder (or other) MHRV systems installed could report back on how you are finding them after a few years?

I am about to build a new home and we are going for high performance (not passive certified but pretty close in terms of performance). Aiming for around 0.6-0.7ACH with triple glazing timber windows, superinsulated walls, roofs and floors etc.

I have decided on the Zehnder Q450 after getting it designed up by Fantech (it is a 256m2 home).

I am just in the process of trying to figure out what additional active heating/cooling I will need to install alongside.

There is quite a lot of glazing on the NW face of the building so there are concerns about over heating in summer.

The current thinking is a ducted heat pump system feeding into these NW facing rooms, which happen to be the main living/dining/kitchen areas, my office, and the master bedroom.

Really interested to hear how your systems are performing, with or without a heat pump in the mix.

Cheers,

Ben

timmmay

20581 posts

Uber Geek

Trusted

Lifetime subscriber

#2709116 18-May-2021 17:27

If you go with a ducted heat pump make sure you get one with zones that has a thermostat in each room and adjusts temperatures in each room individually. Simple zones you can turn on and off would be frustrating as you would have to mess with it.

We have one north facing room and it gets a lot hotter than the rest of the house, so when we cool that room the rest of the house is a freezer. We already left one very sunny room with a highwall heat pump because it's really a completely different temperature zone. A friend with a new house has two ducted systems, one for each temperature zone, but without individual room control. Our replacement system that should do the job is going in late June, Daikin with an Airtouch 4.

akmodi

26 posts

Geek

#2709148 18-May-2021 18:43

Hi,

We built something similar before with NZSIPS panels, triple glazed upvc German windows.

We used the Q600 and it's been great.

Happy to help if you need more information.

Thanks

SumnerBoy

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#2709166 18-May-2021 19:01

Yeah I have only just started looking at the ducted units but will definitely be looking for something with room controls.

@akmodi - do you have any active hearing and cooling to go alongside your MHRV system? How do you find the heat exchange in the depths of winter? Does the cooler air coming in cause the house to cool down a bit?

akmodi

26 posts

Geek

#2709170 18-May-2021 19:06

Hi Sumnerboy

We put in individual small units with high COP and SEER ratings. The heat recovery system of Zenender units automatically spreads the heat in the home.

They have been very good in giving good ventilation and preventing heat loss

SumnerBoy

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#2709308 18-May-2021 20:51

Hmm - I can see how individual units would provide the most control - but a ducted system is around $8K and I don't think I would be able to get 3 units for under that (for the 3 rooms I would need).

All 3 rooms are on the same side of the house, but of varying sizes. So I am hoping they will have similar requirements.

I will do some more research into what control mechanisms they come with and ensure I can control each room individually.

Good to hear you are happy with your Zehnder tho!

timmmay

20581 posts

Uber Geek

Trusted

Lifetime subscriber

#2709317 18-May-2021 21:06

SumnerBoy:
Hmm - I can see how individual units would provide the most control - but a ducted system is around $8K and I don't think I would be able to get 3 units for under that (for the 3 rooms I would need).

All 3 rooms are on the same side of the house, but of varying sizes. So I am hoping they will have similar requirements.

I will do some more research into what control mechanisms they come with and ensure I can control each room individually.

Good to hear you are happy with your Zehnder tho!

Are you talking about a ducted heat pump? $8K is bargain basement, for a better quality system you are paying $11K or more for 10kw, plus another $2k to $3k If you want individual room control.

Don't buy Panasonic. Very loud, indoor and outdoor.

Sharesies

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

SumnerBoy

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#2709319 18-May-2021 21:18

This is for a Mitsibishi Ducted PEAD-M7J1JAA-S (7.1kW cooling/8.0kW heating).

This is a near passive house so the heating/cooling demand is low. No need for a bigger unit.

But that price doesn't include any room control - so I am yet to hear back how much that will add to the cost.

Any feedback on the Mitsi PEAD units?

timmmay

20581 posts

Uber Geek

Trusted

Lifetime subscriber

#2709329 18-May-2021 21:35

SumnerBoy:

This is for a Mitsibishi Ducted PEAD-M7J1JAA-S (7.1kW cooling/8.0kW heating).

This is a near passive house so the heating/cooling demand is low. No need for a bigger unit.

But that price doesn't include any room control - so I am yet to hear back how much that will add to the cost.

Any feedback on the Mitsi PEAD units?

Mitsubishi are generally regarded as very good quality, along with Daikin and probably Fujitsu. Mitsi I think does room controls but I think it's manual zoning. Airtouch 4 is $2000 to $3000 probably the upper end.

SumnerBoy

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#2709331 18-May-2021 21:44

timmmay:

Mitsubishi are generally regarded as very good quality, along with Daikin and probably Fujitsu. Mitsi I think does room controls but I think it's manual zoning. Airtouch 4 is $2000 to $3000 probably the upper end.

Yeah I have asked about their zone control options, yet to hear back.

I don't know much about Airtouch 4 tho - how does it integrate with the various ducted heat pump vendors?

I just found this which is promising... https://github.com/LonePurpleWolf/airtouch4pyapi

timmmay

20581 posts

Uber Geek

Trusted

Lifetime subscriber

#2709334 18-May-2021 21:51

Ask me in a couple of months. There's a recent thread on Air touch somewhere around here, can't find it on my phone sorry.

SumnerBoy

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#2709337 18-May-2021 22:01

timmmay: Ask me in a couple of months. There's a recent thread on Air touch somewhere around here, can't find it on my phone sorry.

Found it - https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=274445 - thanks for the heads up... reading now...

akmodi

26 posts

Geek

#2709338 18-May-2021 22:07

We put in Hitachi heatpumps that we bought from Mitre10.

Kickinbac

427 posts

Ultimate Geek

#2709344 18-May-2021 22:45

SumnerBoy:
This is for a Mitsibishi Ducted PEAD-M7J1JAA-S (7.1kW cooling/8.0kW heating).

This is a near passive house so the heating/cooling demand is low. No need for a bigger unit.

But that price doesn't include any room control - so I am yet to hear back how much that will add to the cost.

Any feedback on the Mitsi PEAD units?

PEAD are good quality units, you can’t really go wrong with Mitsubishi Electric.

If you are near passive house levels maybe look at putting in three 2.5 or two 3.5 kW hi-walls. Super efficient, quiet, individual on/off & temperature control. You won’t compromise the integrity of your ceiling insulation too. Your HRV system will circulate the heat throughout your home. Mitsubishi Electric have their tiny ecocore AP20 which is a hi-wall unit. Three of those would provide 7.5 kW of heat with a COP of 4.17 for probably less than 8k.
Geez, I’d just prepipe and prewire for them and see how your house performs over a year. Put them in later if you need. You could always use a couple of cheap electric heaters in the coldest part of the year.

akmodi

26 posts

Geek

#2709351 18-May-2021 23:10

That's exactly what we did. we installed: x 5 units of 2.5 kw units each .. with individual units using 750w of electricity.

The units themselves were 990 each + installation.

We just switch on as many as are required.

The issue with a large multi ducted heatpump is that they large a large single outdoor unit that needs switching on ... even for a requirement from 1 unit ... so making them inefficient. Thus they have a low COP.

Hope that makes sense.

BTW: HITACHI at Mitre10 are reasonably inexpensive.

1 | 2 | 3 | 4