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Posted

Hi, I am doing a total house renovation, basically only leaving the facade of the house and rebuilding everything else. I am a total newbie, never done anything like this before and would like to try save some money by buying and sourcing parts and materials myself where possible. I want to put in an MVHR system and because the house is 200M2 I have calculated and cross referenced with quotes that I would need and would like the Zehnder Q450. My question is how do I know what parts I need to get it all installed? I think I have the number of supply and extract valves required (19 in total) and I can run 90mm ducting but what about attenuators, manifolds etc etc? Does anyone know whether I can just phone Zehnder and ask them what I need? Do I have to figure it out myself or do I just give up and pay someone to design and supply the entire system for me?

 

FYI: My username reflects just how over my head I am in this project but I'm trying :)

 

Thank you

SM

Posted (edited)

First let's step back a little 

 

Airtightness, what airtightness measures will you have in place, are you aiming at better than 3m³/m² at 50Pa airtightness?

If not don't waste your money on MVHR.

 

So let's assume you are going airtight 

 

Zehnder is(n't?) the only make, Titan make good basic units, plus many others. eBay can save to loads of money.

 

Basics are MVHR to plenum/manifold, semi flexible duct, room terminal via a 125mm to flex duct adapter housing.

 

You can get smart with through flow, instead of direct flow into rooms depending on house layout. Also known as cascade.

 

Second if not going airtight, do demand activated MEV or dMEV. Fan units run at higher loads when needed and low when not. Silent in operations. Add to this humidity activated trickle vents in all dry rooms. Works at very low base flow, as you generate humidity the system will react. Very little additional ventilation heat loss. Easy to install and pretty cheap, no filters to change out (can get pretty expensive) half the running costs as only extract.

Edited by Nickfromwales
typo?
  • Like 1
Posted
55 minutes ago, Silly Man said:

Hi, I am doing a total house renovation, basically only leaving the facade of the house and rebuilding everything else.

Hi. Have you explored options here for you to possibly become VAT exempt (zero rated) for your project?

Posted
1 hour ago, Nickfromwales said:

Hi. Have you explored options here for you to possibly become VAT exempt (zero rated) for your project?

 

Hi @JohnMo you ask some great questions and I'll get clarification from my contractor as to what level of airtightness he's aiming for but my goal would be better than 5M3 @ 50PA. I have investigated other brands but I like the Zehnder because of it's reputation, noise and heat recovery ratings.

 

Hi @Nickfromwales I have asked the questions but evidently my planning permission is for renovation, not new build so I have to pay VAT and I don't want any delays caused by another planning application.

 

Regards

SM

Posted
36 minutes ago, Silly Man said:

don't want any delays caused by another planning application

Would the cost be much? I haven't looked.

The delay is an issue. But you've got the existing PP and could get started on preliminaries. If memory serves me though you don't start on claiming the vat benefit part way through.

20% can be a lot.

  • Like 1
Posted
56 minutes ago, Silly Man said:

and would like the Zehnder Q450

Expensive for what it is TBH. Check out Air-Haus.com for the price on a Brink 450 for comparison.

 

I've been installing them for years, mostly on PH or thereabouts level projects (well insulated, very airtight (<0.6ach)) with excellent results.

 

You'll have to pay for a design that's worth the paper it's on, but most will QS for a system based on a very rudimentary design (they keep possession of it) from your PP drawings, to provide an indicative quote, so you can get a yardstick. Some will only price design, supply, and fit, some design, supply and commission for eg. CVC in Oxford designed and supplied for all my jobs, and are knowledgeable and helpful. 

  • Thanks 1
Posted
1 hour ago, Silly Man said:

5M3 @ 50PA

MVHR isn't really worth the effort and cost at that airtightness. It will just add to the natural ventilation and increase actual heat losses 

Posted

@Silly Man

 

Anything worse than <1.0 ACH and I'd not bother with MVHR for HR. It's just such slow airflow that the natural rates of infiltration may exceed the flow rates of the MVHR, so just an expensive ornament at that point, and one that'll be pumping cold air into living spaces and bedrooms all winter.

 

Airtightness is #1 on the list, insulation comes after that AFAIC. You can have 1000mm of insulation, but in a draughty house it will still leave you feeling the cold with a big heating bill.

 

Don't forget that if you decide to bite down hard on this subject, which I absolutely think you should, then you can talk to your doors and windows supplier to make sure they don't install trickle vents.

 

If you can get the contractor to follow some basic methodology and build standards from the outset, then getting AeroBarrier involved will get you the AT result that you are possibly, currently thinking is out of reach. If you coordinate this well from Day 1 then you can achieve excellent results for very little extra £££.

  • Like 1
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Posted (edited)
2 hours ago, Silly Man said:

I'll get clarification from my contractor as to what level of airtightness he's aiming for but my goal would be better than 5M3 @ 50PA.

Better still, tell him what level of airtightness you need! There are several threads on here explaining what it's important. If your contractor is already signed up, then you'll no doubt need to do some explanation & negotiation.

 

<1.0 ACH is certainly achievable; targeting the PassivHaus standard of 0.6 maximum would be good. However it''s way better than the average contractor, so they won't get there without added some extra effort, a little extra expenditure (really not that much) and understanding of the techniques and materials. However, don't rely on them to get it right; you'd need to learn about it too, to avoid the potential problems.

 

Edited by Mike
  • Like 1
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Posted

'Check out Air-Haus.com for the price on a Brink 450 for comparison.'      Totally agree, i just took delivery from these guys a week ago. Excellent price.

Posted
9 hours ago, Post and beam said:

'Check out Air-Haus.com for the price on a Brink 450 for comparison.'      Totally agree, i just took delivery from these guys a week ago. Excellent price.

This website doesn't exist.

Posted
39 minutes ago, JohnMo said:

I found the same, but it did a week ago.

 

Yeah, it looks like they haven't renewed their domain.

Posted

I have a phone number 01491 313191 for the sales department.

 

I also have a mobile number from my invoice  but i wont put that up here. Message me if you think this will help.

 

I have to say that the price model they were using, considering they are a new subsidiary of CVC , is a mystery. Perhaps they decided it was not correct.

Posted
13 minutes ago, Post and beam said:

I have a phone number 01491 313191 for the sales department.

 

I also have a mobile number from my invoice  but i wont put that up here. Message me if you think this will help.

 

I have to say that the price model they were using, considering they are a new subsidiary of CVC , is a mystery. Perhaps they decided it was not correct.

Thank you for the number. I just called them and their correct website is air-haus.co.uk

  • Thanks 1
Posted

I put together a list on the website air-haus.co.uk and then also contacted the office using the WhatsApp feature, they then kindly reviewed my list and plans and made some recommendations

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