Is there an inexpensive MVHR diy option?

[Post and beam]

What i saw at the show when i looked inside their unit.  Cheap looking bent tin and electronics that looked like a 4th form GCSE project using an Arduino. Untidy & cheap looking. 

Their summer by-pass was an extra cost add on, dont like that.

Rega vents design was a branched  idea as well which i expressly did not want.

[Nickfromwales]

6 hours ago, Indy said:

Care to expand why?

 

I was also quoted a similar amount for a REGA unit - £5k for supply only, £7k for supply and install. Chose to go with Zehnder based on recommendations (which has turned out to be much more expensive sadly!) but I'd like to understand why REGA are considered so bad.

I could show some pics of installs, ducting like tumble drier hose, held up (strangled) with cable ties, and other such very 1st year apprentice stuff. Looked like fed up teenagers fitted it as part of community service. 

 

Just worse than bread & butter stuff, and failures of whole house systems which needed total gut out by replacement suppliers and installers.

 

As said, avoid. Or don’t. 

[Pocster]

@Wadrian . I did it. That's all you need to know for how easy it was. I think from memory and some years ago unit and pipework maybe 3k ish.

[Pocster]

On 02/07/2026 at 17:42, Wadrian said:

Think I had read £10k on earlier post on Buildhub. Would be good to know if this is wrong 

10K is correct. That's what I charge.

[Nickfromwales]

7 hours ago, Pocster said:

10K is correct. That's what I charge.

He actually only charges £9k, the rest is my manager's fees. 

[Indy]

I know some will baulk at these costs but £10k is exactly what I paid so that number is not unrealistic for a fully designed, supplied, installed and commissioned system. Mine is the Q450 with 90mm ducting 

1. Design - £600 

2. Supply - £6400

3. Commissioning - £500

4. Install - £2500

[Square Feet]

Many thanks for this thread. It's been really useful, cheers.

[LnP]

If you go for the semi rigid radial ducting as recommended by @Nickfromwales, in a timber frame with metal web joists, what do you need to do regarding planning the duct runs. Assuming you're going to buy the kit and organise the installation yourself. Can you get duct layouts done? Who does that?

 

Thanks

[Nickfromwales]

1 hour ago, LnP said:

If you go for the semi rigid radial ducting as recommended by @Nickfromwales, in a timber frame with metal web joists, what do you need to do regarding planning the duct runs. Assuming you're going to buy the kit and organise the installation yourself. Can you get duct layouts done? Who does that?

 

Thanks

Current plant room design:

 

 

Designs via CVC Systems, Oxon, supported and then installed by some good looking welsh fella:

 

 

Ground floor

First floor

7” wide service riser for 18x 92mm ducts for FF into posijoists. 

 

 

Then plaster-in ceiling outlets through, bar a few cheaper ones for where they don’t need the extra time/money. 

 

Basics of layout at the design stage gives me the number of ducts / outlets and then I just crack on basically, adapting to suit reality. Steels were designed in by me, many months before concrete went down, which makes life easier with penetrations where they’re needed; all considered to delete any boxing in or loss of GIA whatsoever. 
 

 

Tres bien 👌

 

[LnP]

No doubt you're Welsh and the jury's out on the good looks 😉.... but I imagine you need to be an olympic wrestler to manipulate all that ducting into place. I recall your preference for radial systems but don't recall the reason. Might a branched system have been easier to accommodate in the building structure and to install? Or is it down to performance? Grateful for a reminder why you prefer radial systems.

 

Thanks

[JohnMo]

1 minute ago, LnP said:

Might a branched system have been easier to accommodate in the building structure and to install

Long lengths of solid metal duct around 125mm dia maybe some of it bigger. Noise attenuation between every room. Great if you don't want to hide it away such as an industrial look. Pretty pants otherwise without loads of pre-build planning to accommodate.

[Bramco]

@Nickfromwales

 

So your distribution boxes are hidden behind walls if I understand the diagram and the photos.

Ours ended up being above the (lowered) plant room ceiling (daft fire concerns as there's no gas)   But....     If you do need to clean each inlet and outlet connection through the semi rigid pipes, how do you do this?   Or is it not considered necessary?

 

[Nickfromwales]

4 hours ago, LnP said:

No doubt you're Welsh and the jury's out on the good looks 😉.... but I imagine you need to be an olympic wrestler to manipulate all that ducting into place. I recall your preference for radial systems but don't recall the reason. Might a branched system have been easier to accommodate in the building structure and to install? Or is it down to performance? Grateful for a reminder why you prefer radial systems.

 

Thanks

There’s no way in hell I’d have got 200mm > 160mm > 100mm spiral metal ductwork in here, plus all the soil and waste pipes, just zero chance. 
 

I prefer the radial as I can fit the stuff in pretty much with zero impact on the layouts, and zero cross talk etc. Seems to run a lot quieter too; this one is a whopper of a system but is absolutely completely inaudible in the rooms on 25% fan power (not commissioned yet, but I expect we can run closer to 20% on trickle).

 

Pulling these flexible (enough) ducts in, one by one, needs thought but is relatively easy for 2 people. Don’t dream of doing this on your own as that’s just too much hard work. It looks ‘lots’ because it is! 40 ducts in total. 

[Nickfromwales]

1 hour ago, Bramco said:

@Nickfromwales

 

So your distribution boxes are hidden behind walls if I understand the diagram and the photos.

Ours ended up being above the (lowered) plant room ceiling (daft fire concerns as there's no gas)   But....     If you do need to clean each inlet and outlet connection through the semi rigid pipes, how do you do this?   Or is it not considered necessary?

 

Made them all myself on site. 4x 160’s over the office to outdoors (vs out next to the front door, yuk!) to 2x 200 (1 per unit), probably lost 2 pints of blood with all the sharp edges…..all part of the ‘fun’.  

 

Doubled up on the black rubber o ring seals and then 2 full turns of AT tape for good measure. 

 

 

And in the plant room posi joist voids I made 2 more 200> (x)qty 100mm ‘manifolds’ which were facing upwards, for supply and extract on the 1st floor.

 

 

Where it was near impossible to apply the foil insulation to the fresh intact I just used cans, lots of cans, of expanding foam aka Kingspan in a can. 

 

 

Mummified it as you can see, to deal

with 0°C incoming air temps / condensation control.

Air-tightened with FM330 and green smartply, so MBC could tape to my bits without losing any integrity (scored 0.35ACH on the test last week ).

 

Zero need to get into these ever again, as the distribution systems are all zero maintenance.

[JohnMo]

Or a more modest normal install. I have a 5 flow and returns on one unit and 2x on the other. 

[Post and beam]

I have 9 supply and 6 extract of 90mm Ubbink, which is what those pictured above seem to be. My MVHR unit is in the loft.

To get from the loft to the ground floor ceiling i had a double stud wall designed into the Potton kit with a 100mm gap. This allowed me to hide the vertical drops neatly. Potton said ' oh thats a good idea'.  

Manipulating the ducts 90 degrees to get them into the Posi joists at the ground floor ceiling was the hardest bit. And remembering to lay them in the correct order such that they weren't needing to cross each other as they distributed away to the ground floor rooms. The trick is ,you need to try to get the twists out as you go because its a total bastard to think ' i'll sort that once its in'. Ask me how i know.

Only other real issue was trying to remember and calculate what end pieces and joins you might need to clip it all together. Waiting for the little bits that you forgot to order is painful.

I have to say the Ubbink ducting is brilliant. If you ever played with Lego as a kid you will appreciate the way it just works and clicks together 'just so'.