In a previous life I designed
and managed the implementation of new retail store spaces which gave me just the
tiniest taste of how rewarding it must be for an architect to see their creation move from a
concept on paper or screen all the way through to a fully built end product. You do get a tangible
result that brings a huge sense of achievement. I guess that's why so many architects prefer to
create brand new structures from scratch. And as we saw in our recent video about Passive House
standards, new builds also offer the opportunity to include the kind of energy efficiencies
that'll be crucial to a more sustainable future. But there's another stream of architectural
work that's much less glamorous and arguably far more important from an environmental point
of view, and that's the enormously difficult task of retrofitting existing buildings.
According to the website 'Architecture 2030' existing buildings generate nearly 40 percent
of annual greenhouse gas emissions and about two-thirds of the buildings that are
standing today will still be there in 2050. So this week I'm having a think about how the
architectural and building industry is responding to these big challenges and what the average
homeowner can do to create energy savings in their existing property to get themselves moving
towards that all-important Passive House standard. Hello and welcome to Just Have a Think. I'm sure
quite a lot of you folks watching this program will, like me, have dreamt of creating your
perfect living space at some point in your life. But not many of us will ever get the
opportunity to build our own home from scratch. And of course there are others who love the
home and neighbourhood they're already living in and wouldn't want to move anyway but who
have houses that don't meet any of the energy certification requirements and that are
costing them a fortune in fuel bills each year. And then there's the rapidly growing number of
people living in rented accommodation and social housing as a result of the societal move towards
greater urbanization and the relentless rise in property prices. The vast majority of those
buildings will need to be radically overhauled as part of the global drive towards greater
sustainability over the coming decades. So retrofitting looks set to become a crucial
activity, not just for private owner occupiers, but also for landlords and municipal authorities.
Retrofitting isn't just about bolting some add-ons like solar panels to your roof to reduce your
electricity bills, although that is an extremely good idea in its own right. No, it's really
predominantly aimed at greatly reducing energy consumption in the first place by significantly
improving the fabric of the building itself to increase its thermal performance and comfort.
The challenge is knowing how far to go and how much comfort and performance any retrofit measures
will genuinely deliver. The industry bods have two levels of improvement that they generally
refer to. The first is called a shallow retrofit, which is fairly superficial, and may only mean
bumping up the insulation in your loft and fitting a more efficient boiler. The second level,
unsurprisingly, is called a deep retrofit and it's a whole different ball game altogether. So how do
you know which category your works fall into and what standards are in place to assess them? Well
we already know about the Passive House standard but it's almost always physically impossible
to reach that lofty goal in an already existing building that wasn't designed that way in the
first place, so some allowances have to be made and those are reflected in a globally recognized
refurbishment standard called EnerPHit, and a couple of European spin-offs called OutPHit and EuroPHit
( see what they did with the PH there? Genius!) In existing buildings architects are limited by
geometry, orientation and structure. There may also be thermal bridges that are difficult to
completely eliminate and that provide a path for heat to escape through gaps in existing insulation.
The EnerPHit standard takes all that into account and sets a lower performance level than Passivhaus
which can be summarized like this. The building has to achieve a space heating and cooling demand
of 25 kilowatt hours per square metre per year compared to the 15 kilowatt hours per square metre
per year required for Passive House certification. It also has to reach an air tightness of one
air change per hour instead of 0.6 under the Passivhaus standard. So retrofitting is not
easy and while EnerPHit is not as strict as Passive House, it's still a pretty tough standard
to achieve. The first thing to aim for is a high level of internal or external insulation, not just
in the walls, but also below the ground floor and in the roof spaces. Retrofitters have to calculate
very carefully where to install insulation to achieve the best results without causing other
consequential problems. That's trickier than it sounds. For example if you just stick a bunch
of insulation on the interior side of a wall you might make the room warmer but you'll
also inevitably make the external wall colder. If that wall is made of a porous material
like breeze blocks or some types of brick then you could be blocking off its ability to
get rid of moisture, which can result in damp and mould - which you don't want! So if an external
wall is very exposed to the elements then the internal insulation may not be your best bet and
you'll probably have to consider adding a layer of insulation onto the outside surface which
will then typically require a rendered finish. You'll also need to install high performance
triple glazed windows and external doors, and the designers will usually need to consider
how they can make significant improvements to the insulation and taping around the window
and door frames and cavities as part of any new installation. Once you've achieved these
improvements in the sealing of the building envelope, then just like with Passivhaus design
a mechanical ventilation and heat recovery or MVHR system will need to be installed. You may
also be well advised to replace your existing heating system with a ground or air source heat
pump, which is something we've looked at a couple of times on this channel, and I'll leave links to
those videos in the description box below here. If you are going to take the plunge though and
go through the pain of gutting your home to make these major investments in future proofing
then there's probably not much point in skimping. The benefit of using the EnerPHit
certification as your benchmark is that you'll be forced to comply with the rigour
and quality assurance that the standard demands. That means you'll likely need to employ an
experienced team of designers and builders who know how to carry out the works to ensure
that the air tightness performance is achieved and that there are no hidden shortcuts taken at
any stage in the process. The EnerPHit certification process is exactly the same as Passive House
certification. To meet the requirements the project must be designed using something called
the Passive House Planning Package or PHPP, which is a software-based calculation tool used
by architects and planners to assess a building's heating cooling and primary energy demands and
recommend appropriate levels of remedial works. And the finished project has to be certified by
an accredited Passive House certifier. The cost of an EnerPHit retrofit will obviously vary greatly from
building to building and from country to country so if you're thinking of embarking upon a
project then you should seek the advice of your local Passivhaus organization. Fortunately
Passivhaus is now pretty much a global standard so you should have no difficulty
getting guidance for your own project, and again I'll leave links to some of
those websites in the description box below. As a very rough rule of thumb though according
to the UK home building and renovation website a deep EnerPHit standard retrofit budget will
likely be somewhere between £800 and £1000 per square metre with an MVHR unit installation
for an average size house coming in at about £10K and triple glazed windows and
doors costing around £400 to £600 per square metre. The bulk of the rest of
the cost comes from the labour intensive work to install all the insulations, membranes and
intricate tapings around protrusions and junctions that ensure the air tightness measures required to
get certification. That work is very time consuming, and it has to be done with great care because much
of it is covered up after it's completed and you really don't want remedial works at the end of
a project like this. There's no question it's a big financial commitment but depending on where
you live there may well be grants and incentives available from state or national government. Over
in Ireland for example homeowners can get as much as 50% of their retrofit costs subsidised
by that country's Sustainable Energy Authority, and that level of central funding is really
something that needs to form part of the green recovery plans in every developed nation in the
world. A deep retrofit project can take a building from an energy performance certificate rating
as low as F or G, which is basically a damp leaky shell that's impossible to keep warm in cold
weather, all the way up to an A-rated home that comes somewhere close to the energy efficiency
of a purpose-built Passive House construction potentially reducing energy demand by 80%
and carbon dioxide emissions by 90%. People who've gone through the process talk about
the transformation in their comfort and health, with a constant year-round ambient temperature
within the whole home, and a lovely crisp clean air supply from the ventilation system, all
achieved with negligible heating and cooling bills. And of course once you've got your official
certification you will have significantly improved the value and marketability of your home. In truth
the world is miles behind where it should be in applying these energy saving measures to domestic
and public buildings, but awareness is growing and the EnerPHit standard is gaining
traction in many parts of the world. Examples of successful retrofits are easy to find
online at websites like Passive House Accelerator who've got an entire section specifically
dedicated to case studies from all over North America and the wider world. I'd highly
recommend this interview with James Traynor from the Royal Institute of British Architects,
who's written a book all about the EnerPHit standard. And of course there are numerous YouTube
videos showcasing successful retrofit projects from the United States, Canada the UK,
Europe and Australia, to name just a few. And many local authorities are now also
beginning to understand their obligations as part of the climate emergency to invest
heavily in major improvements to their social housing stock, much of which hasn't been touched
for decades. Some of those buildings have become so badly insulated and leaky that the residents
simply can't afford to pay the huge cost of heating their apartments properly. The consequence
of that is a level of persistent cold and damp that in many cases is causing chronic respiratory
illnesses in long-term tenants. We talk about some pretty amazing technological breakthroughs on this
channel which will no doubt be very important for reaching net zero carbon emissions by 2050. But
many of the best solutions don't rely on fancy new machines or ambitious and unproven geoengineering
concepts. They're right in front of us - hidden in plain sight as they say. Investing rapidly,
efficiently and effectively in our existing buildings and national infrastructures will not
only massively drive down greenhouse gas emissions but it'll also create hundreds of thousands of
well-paid jobs for at least a generation to come. Now, if you've been through a deep retrofit
yourself and you've got some top tips that others could benefit from, or if you have direct
experience of working in the Passivhaus and deep retrofit industry, then dive down to the comment
section below and leave your thoughts there. That's it for this week though. This channel would
be impossible to maintain without the amazing folks over at the Just Have a Think Patreon page.
They enable me to keep the channel completely independent and keep these videos a hundred
percent ad free, and I'm immensely grateful for the support they provide. And I must just give
a quick shout out to the folks who've joined since last time with pledges of $10 or more
a month. they are Glenn Little, Ty Haller, Shahaf Benita, LJ Nissen, Andrew Tech, Mike Howe, Byron Wolf, Rashid Mostafa, Stephen Leeb, Robert Doxtator Lawrence Kearns, Mike Hopkins, Mark Fermor, Matty
C, Andrew Ruefener, Oliver Reinhard, Robert Ottard and Joanne Gallius. And of course a big thank you
to everyone else who's joined since last time too. You can get involved in that and get the
opportunity to exchange ideas and information, plus watch exclusive monthly news updates from me
and have your say on future programs in monthly content polls by visiting www.patreon.com/justhaveathink. And you can hugely support the channel absolutely for free by subscribing
and hitting that like button and notification bell. Dead easy to do all that. You just need to click
down there or on that icon there. As always, thanks very much for watching, Have a great week, and
remember to just have a think. See you next week
