Passive House Design Costs

[Nicolas]

I have read quite a few discussions about architects' fees, but my question is specific to the cost of designing a Passive House. We're not too bothered about certification, but want the design confirmed via the PHPP. We are likely to use a timber frame from the likes of MBC, PYC Construction etc. Around 130-160m², flat plot with existing services.

 

I was about to contact an architectural practice, but noticed that they quote £8.5k to get to a planning submission, then £20k for working drawings. I assume that the latter includes Building Control drawings. All plus VAT. £20k seems excessive, especially as most (all?), of the section and junction details will have been used repeatedly on previous projects.

 

Roughly how much has anyone paid for planning drawings and the associated application plus construction drawings for a Passive House?

 

On a related note, do experienced timber frame companies even need detailed construction drawings? 

[JohnMo]

Daft question - if MBC say are designing the house to passivhaus spec, what is the architect adding to the party?

 

So then you use a normal architect with MBC. Architect does the broad design stuff, MBC the details of thermal bridging, airtightness etc

[Nicolas]

56 minutes ago, JohnMo said:

So then you use a normal architect with MBC. Architect does the broad design stuff, MBC the details of thermal bridging, airtightness etc

Thanks, that's what I'm wondering, although it assumes that the design for planning permission is good enough to meet the PH requirements. I have been tempted to buy the PHPP to see how difficult it is to use.

 

I'll ask a few timber frame companies - the websites I've looked at don't make it all that clear what they need from customers or what they provide in terms of design.

[JohnMo]

1 hour ago, Nicolas said:

good enough to meet the PH requirements

Form factor makes a huge difference, to insulation levels needed.

[marmic]

for planning stage design we followed passivhaus rules of thumb and submitted old school pencil drawings and statement (by me - cost was a huge amount of time!) and stated passivhaus, but didn't state certified. Once planning approved we then developed design further and paid consultant to run through phpp and we were bang on.   We are hitting passivhaus high performance but not quite certified level however (wouldn't have paid for a plaque anyway!) which I had anticipated -  simple reason form factor as we are only single storey app 100m2 - as JohnMo states form factor is important.  yes the theory is use phpp at planning, but with some common sense and careful thought I didn't believe I needed to - which I didn't.  

[Nicolas]

Thanks for the reassurance marmic, that's very helpful. I do have a fairly good understanding of passivhaus principles and a familiarity with relevant build methods, so have been tempted to do the planning submission and PHPP myself - but there's the time factor, dealing with planners and fear of ending up with a home that doesn't perform as expected.

 

How did you find a consultant, other than picking someone from the PHI directory? Feel free to message me.

 

What was your build method? Did you have detailed design drawings?

[marmic]

https://www.thehealthyhome.uk/

 

[Duncan62]

31 minutes ago, Nicolas said:

I do have a fairly good understanding of passivhaus principles and a familiarity with relevant build methods, so have been tempted to do the planning submission and PHPP myself.

 

I would highly recommend doing it yourself if you have the time and inclination.

 

I did all our planning drawings and PHPP. The cost, as said, it time. But compared to the quoted costs, seems like a bargain. Takes a long time to earn £20k after tax too.

 

No one will care about it as much as you. 

 

Id say consider Passivhaus certification. As a proportion of total cost it is low, Circa £2.5k AND the initial design reviews will correct any errors and guide you in the right direction.

 

[Alan Ambrose]

PHPP is a 20-30 page spreadsheet. Pretty complicated but not indecipherable. The manual is pretty good and a good primer on relevant building physics. Highly suggest using PHPP if you’re not daunted by big spreadsheets. You may want to, or may have to (depending on your BCO) get it checked by a kosher PHPP ‘expert’. It will let you make tradeoffs on your design e.g. window schedule vs. overheating.

[Nicolas]

Many thanks, to both of you. I'd looked at Richard Bendy's website, but it's encouraging to find someone who has used his services. The certification suggestion is certainly something to mull over.