Passiv house costs.

[Oz07]

https://www.bbc.co.uk/news/articles/cg5l3z7p922o

 

Just reading this article they claim building to passiv standard is 5% extra for houses (semi) and 2% (flats). I wonder why they don't include detached. 2 and 5% seem unbelievable to me. Perhaps detached is a lot higher? Don't forget all the boffin work that goes into designing these houses and understanding how all the different elements will interact. 

 

They talk of the new future homes standard next March. I will ask AI what the implications will be.

[Oz07]

Seems that institution is a trade body. Its basically propaganda that article. 

 

Interestingly the changes don't seem too extreme to me. U value targets are similar. Airtightness is ok don't think I've ever been over 3. It does appear to be more aggro so hopefully I can get planning and b regs sorted before March. 

 

Wonder how these changes will effect the housebuilding targets. 

[-rick-]

With the current building regs, meeting passivhaus standards isn't that much of a leap (assuming you are building with quality/well finished detail in mind).

 

It used to be our regs were way way weaker and now they are not. The cost of building houses has gone up a lot also and the added cost of insulation, better windows, etc, becomes a smaller part of the overall budget.

 

I can see the cost of doing the paperwork/documentation to get certified as potentially being the main additional cost of going passivhaus with some (more optimal*) designs.

 

* ie, the existing design for the house is a relatively energy efficient shape, with reasonable glazing (heat loss and heat gain perspectives), already has MVHR planned, etc.

[JohnMo]

51 minutes ago, Oz07 said:

Don't forget all the boffin work that goes into designing these houses

Self build pays for that each time, as they are generally one offs. A developer should only pay once for multiple houses.

[Oz07]

6 minutes ago, JohnMo said:

Self build pays for that each time, as they are generally one offs. A developer should only pay once for multiple houses.

Yes always gonna be more expensive for one offs. Then again I suppose there is the flip side where clever folk like yourself can work out all these interactions themselves. 

 

The AI was saying we do not have enough highly skilled trades to complete enough houses. Sloppy bricklayers with insulation, rough joiners or not enough engineers familiar with heat pumps. I can believe it. 

[-rick-]

4 minutes ago, Oz07 said:

The AI was saying we do not have enough highly skilled trades to complete enough houses. Sloppy bricklayers with insulation, rough joiners or not enough engineers familiar with heat pumps. I can believe it. 

 

Indeed, standards are getting tougher which should in time lead to better quality (for any project) but lack of labour availability makes things difficult whatever you are doing. The good contractors generally know what they are worth given availability.

Edited 21 hours ago by -rick-

[Oz07]

32 minutes ago, -rick- said:

With the current building regs, meeting passivhaus standards isn't that much of a leap (assuming you are building with quality/well finished detail in mind).

 

It used to be our regs were way way weaker and now they are not. The cost of building houses has gone up a lot also and the added cost of insulation, better windows, etc, becomes a smaller part of the overall budget.

 

I can see the cost of doing the paperwork/documentation to get certified as potentially being the main additional cost of going passivhaus with some (more optimal*) designs.

 

* ie, the existing design for the house is a relatively energy efficient shape, with reasonable glazing (heat loss and heat gain perspectives), already has MVHR planned, etc.

I'm not sure about that. The u values above are surely not going to be anywhere close to passiv?

 

I get what you are saying though the regs have come on a lot in the last 20 yrs. I think they are at about the right level now for mass market homes. Keeping in mind end users. There is nothing against individual builders going the extra mile if they want to, or if they think it will help increase value (doubtful)

[-rick-]

Just now, Oz07 said:

I'm not sure about that. The u values above are surely not going to be anywhere close to passiv?

 

0.18 is the regs

 

Depending on the house I've read that 0.15 might be all thats needed to meet passivhaus (there isn't a specific number as passivhaus is more about the overall heat loss which is affected by windows, air tightness, etc)

 

It's not much difference in the quantity of insulation (another 50mm)?. The detailing is stricter and really once you are in this range air tightness matters much more. If you focus on that you need less insulation.

[MPx]

Well we're finding it hugely expensive so I'm not surprised its not viable commercially.  Our passive house is going to cost way more to build than it will be worth on the market thereafter.  Latest example:  We have an integral garage.  Garage outside the passiv envelope, hallway inside.  Door from garage to hall very nearly impossible to source.  You can buy any number of FD30 rated fire doors for a few hundred quid as required by BC in that location.  You can buy quite a few doors adequately rated for thermal efficiency and airtightness and they cost low thousands.  But try to find a door that covers both angles and that's a tad harder.  After a 6 month search I've found two companies who will make me one.  One for £7k the other £8k.  That's a lot of money for one internal door!

[Oz07]

27 minutes ago, -rick- said:

 

0.18 is the regs

 

Depending on the house I've read that 0.15 might be all thats needed to meet passivhaus (there isn't a specific number as passivhaus is more about the overall heat loss which is affected by windows, air tightness, etc)

 

It's not much difference in the quantity of insulation (another 50mm)?. The detailing is stricter and really once you are in this range air tightness matters much more. If you focus on that you need less insulation.

My last place was built to those u values with good airtightness (less than 1 I think on the normal test) and mvhr and I wouldn't of thought it was anywhere close to passiv. I remember doing at energy used per sqm thread on here years ago at the time. 

[mjc55]

How long though before houses are being built by robots?

 

https://www.bbc.co.uk/news/videos/cgljl9zp47xo

 

They will work 24 hours a day, to exacting standards.  I would imagine that passive would be easy for them to achieve.

 

I used to think that it was the trades that would benefit from AI as they will still have jobs whilst others won't - now I am not so sure. 

[Oz07]

33 minutes ago, mjc55 said:

How long though before houses are being built by robots?

 

https://www.bbc.co.uk/news/videos/cgljl9zp47xo

 

They will work 24 hours a day, to exacting standards.  I would imagine that passive would be easy for them to achieve.

 

I used to think that it was the trades that would benefit from AI as they will still have jobs whilst others won't - now I am not so sure. 

I wouldn't hold your breath. I'm sure it is coming eventually but surely we are talking decades rather than years

[mjc55]

21 minutes ago, Oz07 said:

I wouldn't hold your breath. I'm sure it is coming eventually but surely we are talking decades rather than years

Can't disagree, it might take a few years, but I suspect that it will be here before long.

 

I'm very glad I am in my 60's, I'm not sure how the world looks for those much younger than me.

[saveasteading]

6 hours ago, Oz07 said:

2 and 5% seem unbelievable to me.

 

It is nonsense. The author is either a very poor architect for normal buildings or is spouting propaganda ... which AI has spotted

Compared to what?   Compared to an untrue figure.

I'm guessing, but 30% more for passivhaus compared to building regs?  Plus the fees  for approvals and the consultants who prepare it.

I think the discussion has been on here before. I've a feeling that the payback period was infinite.

We have never had the slightest intention of going passivhaus as it is an expensive badge. Most of the principles are unchallenged and anybody can do some or all of them.

 

 

6 hours ago, Oz07 said:

Its basically propaganda that article. 

Yes I read it this morning and was astounded.  I guess the trick is to write the 'article' in lay person language exactly when the general public are interested for the first time. 

I think it should have a statement at the start... this is an opinion piece by an interested party.

 

On the 'costing the earth' prog on Radio 4 last week they had 3 or 4 architects and no other construction experts, so this must be the perception of how buildings are designed. Fortunately the presenter was down to earth and questioned the trendy, 'shiny' non- sustainable  buildings that are publicised in the magazines and brochures.

And one of them hadn't read the brief and quoted an eccentric building as her favourite in the world.

On the whole it was very interesting.

I did like the cop-out , or honesty, at the end of the article saying it was a good idea to cover big windows.... I guess the author hadn't thought about it, and now has an old sheet hanging over the window.

 

 

4 hours ago, mjc55 said:

How long though before houses are being built by robots?

 

The robot 'olympics' in China today featured athletics and minor house duties.

At an exhibition recently a Chinese company was promoting a plastering robot. There was only a film of it, but it was fast, precise and untiring. For standard houses it must be worthwhile... not that we discussed the cost.

 

[Oz07]

11 hours ago, mjc55 said:

Can't disagree, it might take a few years, but I suspect that it will be here before long.

 

I'm very glad I am in my 60's, I'm not sure how the world looks for those much younger than me.

Infinite abundance?!

[Oz07]

8 hours ago, saveasteading said:

 

It is nonsense. The author is either a very poor architect for normal buildings or is spouting propaganda ... which AI has spotted

Compared to what?   Compared to an untrue figure.

I'm guessing, but 30% more for passivhaus compared to building regs?  Plus the fees  for approvals and the consultants who prepare it.

I think the discussion has been on here before. I've a feeling that the payback period was infinite.

We have never had the slightest intention of going passivhaus as it is an expensive badge. Most of the principles are unchallenged and anybody can do some or all of them.

 

 

Yes I read it this morning and was astounded.  I guess the trick is to write the 'article' in lay person language exactly when the general public are interested for the first time. 

I think it should have a statement at the start... this is an opinion piece by an interested party.

 

On the 'costing the earth' prog on Radio 4 last week they had 3 or 4 architects and no other construction experts, so this must be the perception of how buildings are designed. Fortunately the presenter was down to earth and questioned the trendy, 'shiny' non- sustainable  buildings that are publicised in the magazines and brochures.

And one of them hadn't read the brief and quoted an eccentric building as her favourite in the world.

On the whole it was very interesting.

I did like the cop-out , or honesty, at the end of the article saying it was a good idea to cover big windows.... I guess the author hadn't thought about it, and now has an old sheet hanging over the window.

 

 

 

The robot 'olympics' in China today featured athletics and minor house duties.

At an exhibition recently a Chinese company was promoting a plastering robot. There was only a film of it, but it was fast, precise and untiring. For standard houses it must be worthwhile... not that we discussed the cost.

 

https://www.bbc.co.uk/programmes/m001m4rs

 

Is it this one? Might download for a drive if its interesting 

[Oz07]

13 hours ago, MPx said:

Well we're finding it hugely expensive so I'm not surprised its not viable commercially.  Our passive house is going to cost way more to build than it will be worth on the market thereafter.  Latest example:  We have an integral garage.  Garage outside the passiv envelope, hallway inside.  Door from garage to hall very nearly impossible to source.  You can buy any number of FD30 rated fire doors for a few hundred quid as required by BC in that location.  You can buy quite a few doors adequately rated for thermal efficiency and airtightness and they cost low thousands.  But try to find a door that covers both angles and that's a tad harder.  After a 6 month search I've found two companies who will make me one.  One for £7k the other £8k.  That's a lot of money for one internal door!

I've been thinking about this. Not an ideal solution but one which should pass? Have a non fd rated passiv level insulated door opening into your hallway, and a fire doorset immediately behind opening into the garage. Depending what is stored in the garage after sign off you may want to remove fd? If the garage size and position of opening allows you may even like to build a small stud lobby within the garages. Insulated door into house, fire line the stud and fire door on the stud going into garage?

[garrymartin]

8 hours ago, saveasteading said:

I'm guessing, but 30% more for passivhaus compared to building regs?  Plus the fees  for approvals and the consultants who prepare it.

 

It very much depends on form-factor (easier to make savings on apartment blocks than one-off detached houses), but it is nowhere near 30%, and in some cases has been shown to deliver savings. And of course it also depends on whether you are certifying or just building to the same standards.

 

This article https://www.coldwellsbuild.com/journal/are-passivhaus-homes-more-expensive-to-build has some better links, including to an Exeter City Council report showing how they have continued to reduce costs over the years - "Due to Exeter’s long-term commitment to Passivhaus they have developed unique expertise and experience which has enabled them to refine their delivery models and processes to drive down the cost of Passivhaus. This is reflected in the reduction in the cost premium for Passivhaus from 20 per cent in 2009 to 4 per cent cost saving, pre-covid for apartments up to 4 storeys based on the cost plans against Building Regulation compliant low-rise apartments." https://www.local.gov.uk/case-studies/exeter-city-council-passivhaus-exeter

 

 

[saveasteading]

4% cheaper as passivhaus than not. ?

That just isn't true is it, assuming like for like otherwise?

 

Presumably  there are other much bigger differences in terms of form and quality.

Eg I've seen some social housing recently that looks like shipping containers stacked together but appears to be timber construction, without care in finish and simply looks cheap and temporary, as they probably are.

Thanks for the links which I may read later. I'm cynical on the matter, obviously,  and suspect it's more propaganda by the passivhaus lobby.

 

It's OK to do PH. It's a choice and I understand it, and also the need to justify the choice. 

[-rick-]

15 hours ago, MPx said:

Well we're finding it hugely expensive so I'm not surprised its not viable commercially.  Our passive house is going to cost way more to build than it will be worth on the market thereafter.  Latest example:  We have an integral garage.  Garage outside the passiv envelope, hallway inside.  Door from garage to hall very nearly impossible to source.  You can buy any number of FD30 rated fire doors for a few hundred quid as required by BC in that location.  You can buy quite a few doors adequately rated for thermal efficiency and airtightness and they cost low thousands.  But try to find a door that covers both angles and that's a tad harder.  After a 6 month search I've found two companies who will make me one.  One for £7k the other £8k.  That's a lot of money for one internal door!

 

The problem you describe here is one that has come up several times on this forum (for people who are just trying to be energy efficient, not building to passivhaus standards). Integrated garages impose a lot of extra costs that aren't obvious when the architect first draws them. That said, they are often the only option in many plots.

[Oz07]

3 minutes ago, -rick- said:

 

The problem you describe here is one that has come up several times on this forum (for people who are just trying to be energy efficient, not building to passivhaus standards). Integrated garages impose a lot of extra costs that aren't obvious when the architect first draws them. That said, they are often the only option in many plots.

I suppose people could also emit the door into house or have one on an outside wall instead if possible. 

[saveasteading]

1 hour ago, Oz07 said:

this one?

My apologies, and I will now listen to that one.

 

It was a different series called Rare Earth. I think it's this.

https://www.bbc.co.uk/sounds/play/m003011r

Edited 5 hours ago by saveasteading

[ProDave]

Re the garage door.

 

I just fitted a standard FD 30, and then added an extra bead around the door frame and extra draught proof seal around that in addition to the intumescent seal (which is not an airtight seal)

 

The garage door was the one removed for the air test blower door so did not figure in the air tight test results.

[-rick-]

An example of cost saving might be that if you meet passivehaus standards, especially in a compact home, your heating demands are tiny so you can skip the expensive heat pump install and just put in a couple of small electric heaters.

 

Given the tightening of building regs the 'design' cost of a passivhaus is now a much bigger element of the overall cost of meeting the standard. Therefore, if you are working on a standardised design/methodology spread over many units the cost of materials/extra labour to install is relatively small. Again, only talking about properties that have been designed up front to be easy to make passive. Any design can be made passive, but some are relatively cheap and some are very expensive.

 

A lot of custom one-off homes will tend to be in the more expensive as the customers will want nice things like big windows, overhangs, lots of corners and detail or simply to squeeze a lot into a difficult site. Meeting the passivhaus standards then will add a lot more cost than a simple box.

 

Edit: and as others have said, terraced houses, semis and flats are all easier/cheaper to make passive.

Edited 5 hours ago by -rick-

[saveasteading]

1 hour ago, garrymartin said:

nowhere near 30%, 

I accept that, for mass produced and holistically designed buildings, especially apartments.

I was thinking of one-offs as most on BH are.