What are the actual benefits of a 'passive house'?

Depends how long you expect it to stand, and the amount that would be spend heating it if it was not to that standard.

There is nothing magical about this, it is just construction optimised for low heat loss.

It seems however that many UK builders  not really to have mastered thinking logically about this, despite requirements for insulation entering the building standards in 1984.


It also depends how big the place is - when we are talking about a doubling in price it is steep, if it is a 20% increase, it seems more reasonable.


It may well not be all that  reasonable in this case - there may be an element of band wagon jumping to inflate profits.

Mike.

They're small compared with other standard 3 bedroom houses in the area Mike.


In fact they've been a bit cheeky as the original plans show them as being three bedrooms with all three bedrooms and a bathroom upstairs and downstairs a large kitchen diner and a large living room. However, they've now split what was the living room into two to make a downstairs bedroom and a 'study/bedroom' and squeezed space for a sofa and TV into the kitchen/diner area. The whole of the Kitchen/diner/living room area is now only 12 ft x 27ft. Upstairs they've removed one of the bedrooms to make two bedrooms and a bathroom upstairs but because of the configuration of the sloping roof space you only get a small portion of both rooms upstairs where you can actually stand up (probably why they decided to ditch the third bedroom at the back as you wouldn't have been able to stand up in it... ?)


I'm not convinced that spending an extra £300k+ for a passive house just to save me a few hundred pounds a year on heating bills is really worth it? I'd have to live in the house for probably 400 years before I saw any financial benefit! 


I think I'll stay in my cute little two bed cottage.... it's probably bigger.... and much cheaper... ?

You may well be making exactly the right decision - there is a lot of waffle being created at the moment about saving energy by doing things that are actually a dead loss.  This will at some point meet reality with a loud bang and  a sense of disappointment, but we are not quite there, yet.

In addition modern UK housing seems to be designed around people sleeping there and doing precious little else, as there is no room to actually live. If we are serious about stopping folk commuting, and want to encourage more working from home, (which will currently save more energy than all the heating bills combined, but it is money taken out of a different pocket ) then this is moving in utterly the wrong direction.

Ideally houses need to get bigger, not smaller, with some space for kids to play etc.  more than one 'home office' room and have the provision to include all the facilities that one would expect to enjoy at an office-like  place of work.  They need to  be well insulated too, but that needs to be standard, not something you pay extra for, or folk will not.


Mike

This is the first time I've contributed to these discussions, so I hope I'm not going to get anything wrong.  

But this is one topic I feel I can contribute to - I live in an certified Passivhaus.  And we had it built for us (and did some of the work ourselves).  It cost just over £1,000/m2 which I'm told is competitive in 2012 and this included both solar PV (expensive in those days) and solar thermal with associated thermal store (both of which, strictly, are nothing to do with Passivhaus..  Yes, it very much sounds like Lisa's suspicions that it's a rip-off are right.  It need not cost much, if any, more than a conventional house.

The key points are very good insulation and very good airtightness.  The latter forces the use of a MVHR.  In my case the solar thermal generates all the DHW and space heating for about 3/4 of the year.  There's quite a lot of south-facing glazing.  All the glazing bar one skylight is triple glazed - it's a very quiet house!.

Thanks David for your constructive comment but what is MVHR for the uninitiated?

Mechanical Ventilation with Heat Recovery (MVHR) is a whole house ventilation system that both supplies and extracts air throughout a property. It offers a balanced low energy ventilation solution for new dwellings and re-uses up to 95% of the heat that would have otherwise have been lost.

mapj1:


Ideally houses need to get bigger, not smaller, with some space for kids to play etc.  more than one 'home office' room and have the provision to include all the facilities that one would expect to enjoy at an office-like  place of work.  

 

In comparison Mike, there's a lovely riverside development in a town 15 minutes drive away. The houses are large 4 story semi detached town houses with a ground floor layout perfect for home office working and to keep some form of 'boundary' between home and office life. I walk past them frequently on my walks up and down the riverbank and day dream of what it would be like to live in one and spend a summers evening on the 1st floor terrace overlooking the riverside. ? 


At £545,000 they're still way out of my price range but I know which house I'd rather be living in!

David Learmonth‍ - thank you for your reply. It's great to hear first hand experiences from someone who actually lives in a Passivhaus ?. How does it deal with condensation though? Given that it's relatively airtight? When I bought my own house there was a few patches of 'damp' that were attributed by the previous owners to a failing damp course (my house is 146 years old) but we rectified it by simply increasing ventilation. The previous owners had double glazing installed but none of the windows had vents in them so the damp was in fact caused purely by condensation build up.

For anyone interested; The IET Anglian Coastal Network hosted an excellent webinar presented by John Helleur MBE entitled "Active House vs Passivhaus - but is either enough?" last year (Nov 2020?).


In his presentation John draws upon his personal experience of building his own house to illustrate with practical examples the benefits and issues around building and living in an eco-friendly home. I won't say more than that in case I spoil the ending for you.


I've also included the link below which should take you straight to the Webinar on the IET Anglian and Coatal site, but in the event that I've got it wrong its easy enough to ecosia/duckduck/google/bing for (as I did) and you can find the the webinar on the videos tab - dated 23rd Nov 2020.

Active-house versus Passiv-haus - but is either enough?

thank you for your reply. It's great to hear first hand experiences from someone who actually lives in a Passivhaus ?. How does it deal with condensation though? Given that it's relatively airtight? When I bought my own house there was a few patches of 'damp' that were attributed by the previous owners to a failing damp course (my house is 146 years old) but we rectified it by simply increasing ventilation. The previous owners had double glazing installed but none of the windows had vents in them so the damp was in fact caused purely by condensation build up. 

That's where the MVHR comes in.  As the house is so airtight, yes, if there was no ventilation  there would be condensation, stuffiness and eventually breathlessness, I suppose.  The MVHR pushes about 200m3/hr through the house (thanks Andrew, above), which is generally more than you would get with a window open, and ensures that condensation doesn't happen.  Rather the opposite.  We have a sheila/dolly in the utility room.  A load of washing dries on it usually within 12 hours and always within 24hours, winter or summer.  The towels dry in the bathroom. The house is generally on the dry side, being somewhere between 40 and 60%RH.  Unfortunately, it's relatively difficult to retrofit ventilation of this sort, so to get adequate ventilation you lose heat.  I think that all new build should be to PH standard but many housebuilders argue that it's too difficult/expensive.  The last labour gov't brought in the Code for Sustainable Homes with the aim that all new build should be level 6 (PH standard with some extras) by 2016.  But this faded with the coalition gov't and (IMHO) the conservative gov'ts since rolled over to the house builders.  Given the re-emergence of interest in climate change and all things sustainable, this may be changing.  Let us hope so.

Thanks Mark, yes, this is an excellent talk, not least because he did a great deal with his own hands (even more than we did!)  It would be good to have a discussion with him.  I haven't had another look at the talk yet, though I have a memory of being both envious wrt some aspects and not really agreeing with him on others.  And he did his own calculations while I relied on someone else to handle the PassivHaus Planning Package (PHPP) which is the humungous spreadsheet which handles the heat management