Property Perspectives: Conversations defining the future of real estate

Building zero-carbon ready homes

• natwest markets • Season 1 • Episode 5

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The latest trends and sustainability innovations in the world of commercial real estate.

What does it take to build a zero-carbon ready residential development?

In this episode, NatWest’s Ashley Toy is joined by Stephen Andrew, Group Technical Director at Taylor Wimpey, to explore the methods, materials, and technologies powering a pioneering zero-carbon ready home. From early planning challenges through to design and development, they explore what it really takes to deliver sustainable homes at scale.

NB. This was recorded on 13 February 2025. 

Get more tips, tools, and strategies to help navigate your sustainability journey today: 

SPEAKER_00

It's important then just to collaborate against all of this at the moment and because it's it's bigger than any one company. You know, the the the UK industry needs to solve some of these problems and and the UK supply chain needs to solve some of these problems. So it's not an individual developer's problem, it's uh an industry-weight um problem to overcome.

SPEAKER_01

Hello and welcome to Property Perspectives, an outlets podcast all about sustainability in the real estate space. I'm your host, Ashley Toy. Today I'm joined by Stephen Andrew, Group Technical Director at Taylor Wimpea. Thank you very much for coming in. We're here to talk about your zero carbon ready homes. So let's get into it. So I think if we could start at the beginning with all of this. So when you went back to thinking about this project, what what were the problems you were trying to solve and how did you go about thinking about it?

SPEAKER_00

Yes, it's uh quite quite a big challenge, this um and uh very topical for the moment. So um there's a few few parts to this. Uh the overarching part is probably the the government ambition uh around zero carbon. Uh we know that uh the UK government has stated its ambitions around 2050 and around trying to get the UK to decarbonise. So that has an overarching um ambition to this. What sits then in behind from Telewimpi's point of view is that we um actually launched our net zero transition plan back in 2023, which uh committed Telewimpi tax moving a bit faster than that. So we recommitted to 2045 instead of 2050, and within that as well, there were ambitions around 2030 in terms of decarbonising our um house type range. Yep. Um so that by 2030 we were building you know net zero ready homes across the UK. So that that's uh that's our um commitment. Uh and what this trial then was trying to do is understand how we delivered against that that commitment um and testing all of the component parts, which uh you know you can imagine is quite varied. There's specifications, there's compliance, there's building regulations, there's suppliers, there's subcontractors, there's skills, um, and then ultimately in the middle of all of that, uh, and uh you know the most important part is customer. You know, someone's going to buy these homes at the end of the day. So there's a lot of moving parts to consider. Um so the trial essentially was designed to try and address all of that, find out where the gaps in our knowledge were, where they find out where the gaps in our our suppliers and subcontractors' knowledge were, um, and then ultimately try and start to understand what the the optimal specification may well be for our customers as we move towards these zero carbon ready homes.

SPEAKER_01

So I think the the trial point is actually quite pertinent, right? So we're only at trial stage and yet you've still got a lot to do to kind of get this to a to a mass point. So you talked about some of the challenges there. But what were the big hurdles when you were starting to get into this?

SPEAKER_00

Yeah, I think the the hurdles um, you know, the the government's consulted twice now on future home standards. So we're we're waiting for the future home standard to be uh published, which we're expecting to be summer this year. Um, with that, the publication of future home standard, that will also come with the energy modelling software that the developers require to be able to test combinations of specifications and the performance of the houses. So one of our main challenges is we don't have that yet. Um so we are working to what the government has previously published through the consultations, um, which is you know what we understand that to be, then is a 75 to 80% reduction in carbon emissions from our homes from the 2013 building regulations and the very likely electrification of homes. So that's that's two of the kind of fundamental points that we expect to come with the future home standard, and it was two of the fundamental points of our trial. So, how do we electrify our homes? Um, and how do we achieve that that level of carbon emission reduction in our homes? So that that was probably the starting point. For us, then the challenge is uh, you know, if you're setting out on quite an ambitious and coordinated trial, we we chose to do it on a live site, and that was very deliberate. Uh and the reason for doing it on a live site was we wanted to understand the challenges of doing it on a live site with our existing subcontractors, with our existing suppliers, because that would very quickly identify where the gaps in knowledge were, the gaps in skills, the the gaps in the the product pipelines and so on and so forth. So and also just the the natural challenges of building in the the live environment outside. And you've got a supplier base, I guess, that wants to work with you on this. Absolutely. Absolutely. So you know that that was the kind of basis of it. Um after that point, then it was all about finding the right site um because we we wanted to move quickly on it, um, and we couldn't wait for you know a brand new site to go through the planning process, which can often take quite considerable time. So we had to move on a site that was already live or very close to being live, um, and the planning position was such that it could accommodate these kind of future homes within the plots. What was also quite difficult was um we wanted uh to try on as many different house typologies as we could to make it as representative of our house type range across the UK. So we actually set a competition within the business um for all of our 22 business units to come back to us to you know offer sites to us that they think could achieve the brief. And the brief was essentially we wanted five plots that we could isolate from the rest of the site so that when we did get to the point of uh letting visitors come to the site, it was safe. Yeah. Um but over those five plots we wanted detached homes, semi-detached homes, two-story, two and a half story, so we could get quite a variety of um house typologies to test. Well it was a bit of a test, to be fair. It was a bit of a test, so but we did find it. Um and our TWE London um business unit had uh an appropriate site, um, it had planning consent, so we were already on building, and we could carve it this little pocket of five houses that we could uh go and launch the trial again. So that that all worked really successfully, and that model worked really well within our our business as well. So um that that was trial number one uh in terms of uh just identifying the site in the right plots. Then it was actually trying to understand what's what's in the market, you know, what what products exist within the UK. Yeah. Um if you look broader into Europe, Europe, uh some of the European countries have moved faster than the UK in terms of decarbonising. So if you look at um Ireland, you look at Holland, France, um, you know, they've already been building with the air so seed pump and electric technologies for quite a considerable period. Um so we we went to the various countries, we met with uh developers, we met with suppliers, um, and we you know we did a lot of work to understand their experience with uh you know decarbonising housing, fitting some of the specification into houses. Um, and we also have our Spanish operation as well, which is um fully electric as well. So you know we've got good expertise already within our business unit that we could draw some some experience from. So we looked out with the UK, we did look in the UK, um, we engaged with our suppliers uh to understand what they had just now, but also importantly what was in their innovation pipeline, what what hadn't hit the shelf yet that you know we could perhaps offer them the opportunity to trial with us on on our site, which is what we did with quite a few um suppliers. So there was quite a few areas to to look at there. Um our subcontractors had to probably learn quite quickly because you know they're used to to building with us, so they perhaps weren't used to some of the low-carbon tech that we're gonna trial here, but we didn't want to bring specialists in because these are the guys we're gonna have to work with in the future. So we wanted to train them and bring them on and you know test their competencies and learn from them and their experience of introducing us into the houses. Other challenges is actually house type design. Yeah, um, you know, we've we run with standard portfolios across the UK, and okay, they're you know tailored locally to planning requirements and and the likes. But you know, we tried to run a standard portfolio for efficiency. Um, but with electrification, that does change things, you know. Um just now we might build a house with a combination gas boiler, which serves um heating and hot water to that house. When you move to electrification, that could be an air source heat pump, it could be some other technology, but it'll likely require a hot water cylinder in the house. Yeah. Which you wouldn't have space bar just now in a country. Absolutely. So you've got to suddenly find more space, but you don't kind of want to steal it from the customer, you don't want to take it from existing storage within the house. So that's quite a difficult um balance you've got to get right there, and you've got to come up with some innovative solutions, which we're looking at at the moment. Um, other things like sometimes some of the houses, the radiators need to get a lot bigger because it's running at lower flow temperatures within the house. So we see some changes there which then may affect furniture layouts, stair positions, kitchen designs, and so on and so forth. So the design part of the house needs quite careful consideration depending on which specification options you you choose.

SPEAKER_01

Right, I can imagine that whilst you're thinking about this, you could quite quickly find yourself in a position you end up completely redesigning your house type uh without really thinking about it because you're making so many minor changes. So I guess thinking about the technology that you've got, always find it a bit interesting where you've you can have some really interesting tech, but it would it would be so small scale that actually even if you wanted to use it, you couldn't really scale it up. Um so how did you go about making that balance between innovation and new and I guess stuff that was already there but you could apply today?

SPEAKER_00

Yeah, I think um it's a it's a very good point because there were technologies that we trialed that did perform well, but you know, in today's market weren't scalable. Yeah. Maybe in a few years' time they they would be, but right now we couldn't just deploy it across our our business. There were others that we could. Um there's others that when you're looking at Europe, um, you know, trying to ensure there's a robust supply chain into the UK for some of the products, yeah, there's a bit of work to do there. Um, and equally, um, you know, some of the products that were performing well in Europe when we did our tour there, when you bring them back to the UK and you push them through the energy software that the UK um sap assistors use, it suddenly didn't perform as well. Yeah. Um and that can often be down to the electric tariffs versus the gas tariffs and things like that. So, you know, we did have occasions where um one of the technologies we put into the house actually made the house perform worse than the gas equivalent of the house. Um so then we had to put additional technologies into that house to bring it back to an EPCB to be able to sell it. Um so that was that was very interesting because what that taught us was we can't just take something in Europe that's really successful and just drop it straight into the UK and uh expect it to perform to the the same efficiency. Um there were other things as well, you know, like severe source pumps. There's a lot of talk about air so heat pump in the press, you know. Um that that's likely going to be part of the solution for sure. But there's a lot of challenges with air so heat pumps as well, you know, they're they're they're large units, they're heavy. The sequencing of getting them into the plot, you know, we would normally have um boilers connected and drying out the house a bit earlier with an air so heat pump, uh, that that gets delivered later to the plot. So we need to think about our sequencing and timing and things. Equally, things like health and safety about how you get an air so seat pump delivered to location perhaps in the back garden. You know, how do you do that safely? When when do you do that safely? So it changes a few things in terms of how we would approach a house today to how we approach a house tomorrow in terms of installation of that. We were also just on air so sheet pump. Um we were the first in the UK to to install an airsociat pump in the loft. Um, and that was very innovative um and solved quite a few problems because this is you know they're quite big pieces of kit that you know they can vibrate, they can be a little bit noisy. Now we mitigate all of that in our designs and in the houses where we had external associated pumps, we carried out noise surveys and vibration surveys and things to make sure from a customer point of view, you know, it was absolutely satisfactory. Taking them into the loft door removes all of that. Um so the planning authority on the site was particularly interested in the the noise of these machines. Now, when you hear them, they're actually very quiet. Yeah, um, so you know, I don't think there's really a problem there, but you know, we still had to satisfy the plan department putting them into the new, isn't it? So you've got Well exactly, and there's lots of questions, and there's lots of kind of hearsay and different things that that creeps out. So you've kind of got to disprove a lot of that. Um putting it into the loft, you know, created a situation where it solved quite a lot of those problems for us. Um but then it did generate other problems because it's a heavy piece of equipment taken up into the roof space and so on. But you know, it dealt with you know security concerns and and um vibration noise concerns and things. So there's different ways of solving the same puzzle, I think, is what the the trial taught us.

SPEAKER_01

And how I guess we've talked a bit about the suppliers there, you've talked about a lot of things there that impact how a supplier interacts with you and the house. What was their general reaction and like what were some of the things you had to overcome with?

SPEAKER_00

Um well the the the general reaction, and I'd say it's pretty consistent, was they were all excited and very keen to work with us, you know. They were they were keen to test their knowledge, they were keen to test their competence, and um, but they were also recognising opportunities to work with us and trial their own products in in our homes. Um, because ultimately, being a live site trial, these houses were then marketed and sold. Um, so we've got customers living in the five well uh five homes, which we were continuing to measure and monitor the performance of them. So these suppliers also get the benefit of how their products perform. Um, you know, so they probably could get to market maybe slightly quicker with some of the uh the products. So I would say it was very much a partnership with the the supply chain. Um lots of really interesting conversations, lots of learnings, some things that didn't go as as well as planned, and other things that probably performed a little bit better than planned. So, you know, um that's the purpose of the trial. Ultimately, it doesn't all necessarily work. So we're where we identified some challenges, we found ways to overcome that. And I'll you know, as I started to my starting point, was there's a customer at the end of all of this, so we we had to act with the best interests of the customers, and uh that's where we always pulled the conversation back to. And ultimately, on the consumer cost piece, the move to electric, that's one of the most important parts we need to be very careful about getting the consumer cost part right.

SPEAKER_01

Yeah, absolutely. And I guess if you're doing something like a trial and pushing the boundaries slightly, you're probably not pushing hard enough if you're getting absolutely everything right, right?

SPEAKER_00

Well, that's right, absolutely. And you know, I don't think there's an awful lot of value of just testing things that are available on the market just now. You know, there is value in that, um, but the innovation part really pushing the the supply chain to to innovate. Um, you know, the zero carbon journey is not just about house emissions, it's also about things like embodied carbon, um, you know, how much carbon is in that product and the manufacture of that product and getting it to site. So, you know, we've got responsibility there to to push our our supply chain to consider all aspects of their products.

SPEAKER_01

And when we're thinking about the finished product, um what was the market reaction to the finished products, I guess, outside of the customer base, and then maybe if we could move through to what the customers have have said and and how they do.

SPEAKER_00

Yeah, um we we were quite open about this trial. So, you know, I think it's important just now the the industry and it's been proven through some of the industry groups that we we represent our um upon. Um it's important the industry collaborate against all of this at the moment um because it's it's bigger than any one company, you know. The UK industry needs to solve some of these problems, and and the sub UK supply chain needs to solve some of these problems. So it's not an individual developer's problem, it's the an industry-wide um problem to overcome. So that said, we actually opened up, we we bought a visitor centre as part of the trial, so we ended up with about five or six hundred visitors through uh a whole series of guided tours across the summer of 2023. Um, and that you know, that was all sorts. That was internal stakeholders within Telewimpey, um, it was um investors, analysts, it was insurers, banking, uh surveyors, lenders, uh NHBC, HBF, you know, it was a whole plethora of um very interested stakeholders across industry. Um and the response was excellent. So, you know, the feedback was we did do obviously a feedback questionnaire as part of that, and it was overwhelmingly very positive. You know, in the trial itself, um, you know, we we trialled five houses over the different typologies, but each of those individual houses have a had a completely different set of specifications, so there were different combinations of products in each of the five houses. So each house told us something different and told them something different as well. So they found it very interesting um and you know, we shared a lot of information. Uh as I say it's an industry problem to overcome rather than a you know a tailor in uh problem to overcome. Um and we also did um we offered out calls for the SMEs. So HBF organised uh some calls with the SMEs where we had I can't remember exactly numbers, but it was a couple hundred people on from SMEs just to learn our lessons from from our trials. So it was very, very, very open. We shared a lot of information, there was a lot of good learnings from it to to tell industry and tell interested stakeholders, but also to challenge. Yes. Um to challenge, you know, people like um Valiers, surveyors, you know, they're they're stepping into this world of um low-carbon housing. Um, and you know, we were challenging that you know, there was one of the houses um which was very much um designed to not necessarily to meet the future home standard because we think we know what that'll look like. This was test the boundaries of what's possible. So this was a kind of art of the the possible. Yeah. Um and that house had the the the capability of delivering zero bills. It was a smart house that you know traded the energy grids for you, it learned your movements and patterns within the house, when you needed hot water, when you would need lighting, and so on and so forth. So that was quite quite an interesting house. Um but if that had the the possibility of zero bills, then the lenders and surveyors then considered the affordability of that house compared to the existing um housing market, and does that change the affordability calculations? If your energy bills are now dropping down, does that you know change that conversation? So we we were challenging back to the the stakeholders as well. Good, yeah. Um and you know, to to be fair to to all of these groups, it's new for them. You know, everybody's trying to understand this and how it what it means for their business models and and so on.

SPEAKER_01

And classically, people like to have seen stuff proven, don't they? So you've got to do it. There's a bit of a dynamic in the middle. So yeah, great that you're challenging back. And so the people that have been living in the homes probably haven't been living in them for too long, but are you getting feedback? If you've not, when are you planning to do it?

SPEAKER_00

Yeah, so we are we are getting feedback and we've done some sessions with the customers. Um, one of the main things we're doing is actually just testing the performance of the house. So one of the the key principles of the the trial originally was to get seasonal data over the four seasons so we understand how each of the five different specifications um work through winter, summer, and so on and so forth. So we're just about through that now. We're just uh compelling the final data on that. We've now been through the winter cycle. Um so that's again teaching us a few lessons about some of the combinations perhaps working better than expected, some perhaps not working as well as expected, but still well. Um, and this, you know, that it's all part of the trials, just understanding you know what what we think is going to happen, what the the energy software tells us, what the suppliers think the product does to what actually happens. But you know, ultimately the the customers live in their own way in in their house, so they'll demand a different amount of you know, I'd I'd maybe need different heating from you or a different amount of hot water. So you know it's difficult difficult to compare across the five plots, but what we can do is kind of compare against the average of that type of house that we would build under gas, and then you start to understand what the difference is. Um but the the customer feedback's positive. I think there's been um good feedback from customers as well about some of the the products, some of the interfaces with some of the products. Um, I think one of the main challenges the the industry will face is about customer education. Um, you know, things like uh underflow heating, for example, excellent product. But if you're not used to having had underflow heating, you might not understand that it takes quite a long time to heat up the grey floor slab. So you're better to have it on all the time at a very low uh value rather than switching it on and off like you might with a heating system with radiators because it won't perform like that. So there's there's education bits we've we've picked up and we've developed you know education uh for customers in the way of kind of QR codes and animations and things through our show homes. Um so that's that's helped us, but also helped our suppliers develop their products and develop the interface with customers and our products. So customer education I think is critically important, but equally so is the competence of the contractor installing it. And again, they've had a lot of good feedback to us as well from some of the products and some of the challenges they've faced. Yeah, great. So what's the next milestone for you, OpenS? Next milestone. Um so there's a few. Um mentioned future open standards, so we're expecting that to come out in summer. Uh so when that comes out, we will, you know, be moving very swiftly onto testing all of our assumptions, testing some of our conclusions so that we can settle on a specification, firm up supply chain uh arrangements and and prepare for the future in that respect. Um we've got other trials going on, you know, in the same site that we did the Five Plot trial, they're actually we've just recently connected just before Christmas a series of customers onto our first um air source heat pump network uh with GTC. So that's a community-based uh heating network solution. So you don't have any air source heat pump in the plot, it's all done in a compute uh community centre. So that's quite interesting as well in terms of a large, large-scale site. Um so we're monitoring that trial as well. So we're doing lots of innovations still. Um, there's a lot of work around how we accommodate the products in the homes and how we innovate, perhaps where we might put them within the homes, and uh um with the customer in mind again that you know we're not diminishing their experience and diminishing the storage available to them and so on. So quite a lot of working on our in there just now in prep for the future home standard coming. Um so really that that's where we are at the moment. There's there's a lot of trial, a lot of innovation going on just now, a lot of prep work to these regulatory changes that we're expecting this year. So

SPEAKER_01

No, not at all. So I guess uh bringing it uh to the present day lab if you could give one piece of advice to a property developer, what would it be?

SPEAKER_00

I would listen to your customers engage your supply chain early, understand your own subcontract base and what their challenges and limitations and but also experience that they can bring to the table is and then just consider what what you want to choose to offer your customer because I think in the past the building regulations dictated a lot of the homes were quite similar from a specification point of view. Yeah. Whereas now with as we move into future homestanders a lot more choice. Um so you can choose, you know, do you go to your social heat pump, do you go to PV panels, do you go to underfore heating, do you go to radiators? There's all manner of choice now. Yeah. Um so you know, understanding your customer base, understand your subcontractor strengths, and understanding your supply chain, uh, you know, that's that's what you need to get right.

SPEAKER_01

And a final quick fire one for you then. What was the biggest learning for you throughout this process?

SPEAKER_00

Yeah, so the the biggest learning I would say is education. Um, really education, education of our designers um of how they're going to design homes, uh, education of the designers around specification of homes and the combination of specification. Our suppliers, education. Yeah. You know, how are they going to innovate? How are they going to bring these products? How are they tackling carbon emissions, but how are they also tackling embodied carbon? Uh, education of subcontractors, you know, really talented subcontract partners, but this does change things slightly. So, you know, there's some new competencies to learn, there's some new approaches to learn. And then ultimately the um the education of our customers, which comes from perhaps some of our sales exec's teams, um, and how they they explain when they're selling the products to customers. But ultimately the customers are going to be living in these homes which are going to be zero carbon-ready homes, which may be a little bit different from what they're used to living in. Now it is quite exciting. Yeah, you know, it is exciting. Um, but I think we just need to get that education piece right through industry and to customers, and then it will be a success.

SPEAKER_01

Yeah, absolutely. I mean, when you think about, I guess, the border climate journey, we are still in that education piece and moving into action over time. But yeah, you've got to do the education first. So thank you very much. Thank you. That's it for another episode of Property Perspective. So I think you're happy to have toy. Please remember if you enjoyed the episode, click like and subscribe.