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Hi,

 

In the process of deciding which make of unit and associated pipe work etc to go for.  I have a few quotes from different companies which all recommend different units from Zehnder, Airflow and Vent Axia. I have decided to go for a professional design and supply but install it all myself.

 

Before I decide I was wondering what experiences and thoughts people have on what they have and any advice / recommendations.

 

My thought at the moment is to go with a company called Solarcrest, there design service is £780 and they recommend the Airflow Adroit DV145 with Airflex Pro Radial Ducting. Once installed they will inspect and commission for £600.

 

Thanks!

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I've got an AirFlow unit, and am very happy with it.

 

AirFlow can design your system for you, at least they could in 2016. They have a very competent design office. I'm pretty sure that the system design was free, I can find no record of paying for it, accept they charged me £50 + VAT for iteration number 4. But that was after we'd agreed everything, and they'd issued me 45 page design report etc., so I thought that was quite reasonable.

 

AirFlow then provide a full BoM and a target price, and you take that around to all their distributors to get the best price you can. I found that different distributors get different terms with AirFlow, depending on their sales volumes, and it turned out for me that no one could beat Travis Perkins. My local TP didn't have a clue what I was ordering, but they ordered it and delivered it for substantially less than the target price from AirFlow.

 

AirFlow then provided very good telephone support for my self-install and later for getting the communication running between Loxone and the AirFlow unit.

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I used BPC, design was free and they use the Vent Axia Sentinel Kinetic range.

 

Just take layout designs as a guide rather than gospel. You may well find that you need to adapt it to site conditions so having some buffer in ducting materials is a good idea.

 

Depending where you are with your drawings, the MVHR design is a good indicator of where you may need steel or other structural penetrations. 

 

I missed this detail but was lucky to find a few alternative routes, bypassing tricky steel work (ditto for plumbing).

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We have avery simple system from Rega Vent. The main heat exchanger unit is located in the roof space over a porch which means you can't hear it but its harder to clean the filters. We were surprised how frequently the input filter gets blocked up despite only having a coarse filter. We live in a rural area and it seems to be flies and dandelion seeds that are the main problem. So make sure you can get access easily.

 

I've recently 3D printed a filter holder that fits on the inlet vent itself rather than in the heat exchanger. This means we can see the state of the filter without doing anything. No climbing on steps and opening the heat exchanger. Can also remove it for cleaning without needing any tools.

 

The constant ventilation you get is worth every penny. We find towels/shirts/jeans dry quickly on a rack so no need for tumble dryer (except for emergencies) or even a washing line. 

Edited by Temp
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22 minutes ago, dpmiller said:

If you're installing it yourself why would you pay someone £600 for walking round the house with an anemometer?

 

One you can get on loan from the forum for £10

 

Plus £780 for a design you'll get other places for free.

 

£1400 is almost half of what I spent on my whole MVHR system. 

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There's a lot of smoke and mirrors around MVHR.

 

It's a lot simpler than you are made to think.

 

I got my unit from fastlec, and did all my own ducting with blauberg manifolds/pipes.

 

Think I saved £2k and I even bought an anemometer to set it up.

 

The calcs are quite simple in reality, if nothing else times whole livable footprint in m2 by 1.08 to size the unit.

 

Then work out the flows to each room to size the number of ducts if using radial.

 

Solarcrest rang me every few months for 2yrs after I had a quote from them, in the end said I'd done it myself.

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Keep ducts big and short and you can't really go wrong. Two companies I enquired with offered to design for free, I went with one of them, but ended up redesigning it myself as I couldn't face going back to them for the third time after moving the plant room lol. They still got the sale tho.

 

In the end I think my design is better, I've calculated the pressure drop as only 80kpa in each unit on full power. I've lots of 160mm steel duct to install tho...

 

Fyi I'm taking a gamble on a pair of Salda Smarty 3x units from BPC. Fraction of the price of Zehnder.

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4 hours ago, Ryan Bazeley said:

My thought at the moment is to go with a company called Solarcrest, there design service is £780 and they recommend the Airflow Adroit DV145 with Airflex Pro Radial Ducting. Once installed they will inspect and commission for £600.


You’ve background checked them I take it ..??

 

There are a lot of MVHR providers out there who are specialists and understand the theory and technicalities of doing large scale ventilation systems - widen your search ...

 

52 minutes ago, JFDIY said:

The calcs are quite simple in reality, if nothing else times whole livable footprint in m2 by 1.08 to size the unit.


There is a spreadsheet on the forum somewhere that does it for you ..!

 

 

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Wow this is a hot topic! Thanks for the comments / advice.

 

I have had quotes from a few companies all about the same price for the equipment, probably right about the design fee although the free ones I’ve had are very basic. I know it’s not rocket science but I would hate to install a unit and it to be noisy / incorrectly installed when in the scheme of it and how long it will be needed it’s a small cost.

 

Still in two minds what to do there is so much choice and difference in option! ??

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4 hours ago, Conor said:

Keep ducts big and short and you can't really go wrong. Two companies I enquired with offered to design for free, I went with one of them, but ended up redesigning it myself as I couldn't face going back to them for the third time after moving the plant room lol. They still got the sale tho.

 

In the end I think my design is better, I've calculated the pressure drop as only 80kpa in each unit on full power. I've lots of 160mm steel duct to install tho...

 

Fyi I'm taking a gamble on a pair of Salda Smarty 3x units from BPC. Fraction of the price of Zehnder.

Hello Conor, how did you handle the penetrations through the ICF? Did you use an oversized sleeve, or the actual duct? Steel or PVC? Any thoughts would be much appreciated.

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  • 2 weeks later...
On 28/05/2021 at 12:45, Conor said:

Keep ducts big and short and you can't really go wrong. Two companies I enquired with offered to design for free, I went with one of them, but ended up redesigning it myself as I couldn't face going back to them for the third time after moving the plant room lol. They still got the sale tho.

 

In the end I think my design is better, I've calculated the pressure drop as only 80kpa in each unit on full power. I've lots of 160mm steel duct to install tho...

 

Fyi I'm taking a gamble on a pair of Salda Smarty 3x units from BPC. Fraction of the price of Zehnder.

Hi Conor

Genuine question as I'm trying to do a similar thing - is the 80kPa static pressure in the ducts? If so do you not mean 80Pa? Or is it something else?

Fingers crossed for the Smartys. Only they have the answer!

 

P.S. @Ryan BazeleyIf your contact at Solarcrest is Nathan, he's a good guy. He's done the Passivhaus designer's course.

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I am using Solarcrest / Airflow (and have used them before) on mine - they have done the design and first fix now. While you may think the design aspect is chucking up some duct to the rooms it is a bit more involved if you want to minimise tight radius turns (noise) or excess ducting in habitable rooms.  The lad Nathan there does a decent job on the layouts and will tweak if you have queries.

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