De centralised unit for retrofit?

[hotnuts21]

Hi all,

we are still flip flopping between MVHR or not, one of my issues is the recent realisation of how big the units and incoming/outgoing pipes are and where we are realistically put this that isnt the kitchen or office/spare bedroom.  But I have recently come across the option of a decentralised MVHR unit which can be used in retrofit projects and fit into the wall, so take up less room.  The one we have been looking at is the Blumartin freeair 100 with some cascade fans in some rooms.  

 

However there seems to be very little info about this decentralised approach, and two of the freeair units are similar cost to one standard MVHR unit, although there seems to be more monitoring on it. They also only have a 2yr guarantee which always worries me on something you want to last for a long long time.

Any thoughts or experiences of this model or decentralised in general?  I see there was a post from a few years ago but nothing since.

[JohnMo]

The other similar option is Fresh-R.

 

When I was looking, they looked better flows and price.

 

This is the scheme they quoted for me.  House is 190m2.

 

 

[hotnuts21]

  On 13/06/2022 at 15:40, JohnMo said:

The other similar option is Fresh-R.

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I hadnt heard of these, I was going to ask how they compared, but they seem to have a passivehouse award so should be fairly good. Anyone in the UK supply them or is it deal direct?

 

[hotnuts21]

oh and did you go with them in the end?

[JohnMo]

Deal directly. 

 

I did my own design, as there system didn't give the 0.5 ACH required without adding a third unit, for a new build in Scotland, so became cost prohibitive.

[gravelld]

There's also Lunos, if that still exists.

[hotnuts21]

Thanks both, Lunos does still seem to be around, but im struggling to find many UK sellers, same for all the options really. The BluAir at least has a lot of information available, the Fresh-R website is a bit basic, but all 3 are passivehouse awarded, so should be fairy reliable.

@JohnMo how do you find the decentralised system is it worth it?

Paul

[JohnMo]

I didn't go decentralised in the end, but did install two units instead of one.  A small and a large unit.  The small one does the two bedrooms and two en-suites.  I only have to boost the small one when we use the shower.

[HughF]

I'm in the same position, looking at dMVHR units. Lunos are still around, I was chatting to them at the Installer show last month. They do seem to be a bit on the pricey side.

 

Just come across these: https://www.ventilationland.co.uk/product/40954/decentralised-mvhr-unit-o100-mm-with-switch.html?utm_source=googleshoppingUK&utm_campaign=googleshopping-FeedUK&gclid=Cj0KCQjwzqSWBhDPARIsAK38LY9sv8y5tPeyEPH6lJdO42VQvR7AagTCv5jhXEym6Mpwy0W1M5whOLAaAv7EEALw_wcB

 

From a Latvian manufacturer. They are the standard 70 secs one way, 70 seconds the other way sort of thing with a ceramic heat exchanger.

 

They seem fantastic value at that price... No idea if they're any good or not.

[JohnMo]

I also looked at Lunos, and to meet building regs flow rates it was big money. 

 

Just looked at the manual for the the linked ones, the power consumption is 1.5W in normal running and 2W in boost, so well low.

 

You need a unit in each room, as you can't generate a cross flow between rooms.  You maybe 2 in a large living room.

 

 

[HughF]

  On 10/07/2022 at 07:29, JohnMo said:

I also looked at Lunos, and to meet building regs flow rates it was big money. 

 

Just looked at the manual for the the linked ones, the power consumption is 1.5W in normal running and 2W in boost, so well low.

 

You need a unit in each room, as you can't generate a cross flow between rooms.  You maybe 2 in a large living room.

 

 

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I'm looking at retrofit, just to try and improve indoor air quality in winter (summer is fine, we open the windows), not looking to meet regs on a new build.

[JohnMo]

I'm in Scotland so had to meet 0.5ach.  

[HughF]

  On 11/07/2022 at 16:06, JohnMo said:

I'm in Scotland so had to meet 0.5ach.  

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What amount of building work were you doing that meant you had to deal with that regs requirement? Was that windows and doors replacement , central heating replacement, or something else…. Curious…

[JohnMo]

New build

[HughF]

  On 12/07/2022 at 14:43, JohnMo said:

New build

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Ah, ok. Thought it was a renovation project. Thanks for clarifying 

[hotnuts21]

For the record im now back in the opinion of going for a central main unit, and probably a  brink unit, if they ever get back to me!

Paul

[ianbarlow]

Would it not be possible to do both. MVHR in first floor rooms with unit located in loft and gf with dmhvr ? The advantage being minimising duct runs