This time, we're examining the topic of commissioning, particularly when it comes to heat pumps and ventiliation systems.

Joining us are

• Debbie Haynes, OX Place
• Ian Mawditt, Four Walls Group Consultancy

For more hints and tips, see the pages on commissioning at the Future Homes Hub Knowledge Centre.

Welcome to the Future Homes podcast, where we look closely at the ideas, policies and practical challenges shaping how homes are being designed, built and delivered in the UK today. My name is Chris Gaze.

This time we're looking at the topic of commissioning with care, particularly when it comes to heat pumps and ventilation systems. We've got with us Debbie Haynes from developer OX Place and Ian Mordit from Four Walls Group consultancy.

We kick this chat off by thinking about why commissioning seems to be getting ever more important. Here's Debbie to start.

I suppose when we talk through this, we kind of want to separate the process of commissioning as it is in most of our heads, which is that piece of paper and the process that happens at the end of construction.

So when we're talking about commissioning, we are thinking about that, because there's a number of things that people have to look through there they have to look through flow rates, temperature measurements, pump settings, system controls, sighting of the unit, legionella. There's a whole raft of things in there that we would expect to see on our commissioning certificates.

But the point that we make is that the process to ensure good commissioning happens very early on in the design and build cycle for us.

So even pre planning, we'd be thinking about siting of units, we'd be talking that through, and then there's the detailed design, there's all those steps. So for me, commissioning is.

It's not just that piece of paper at the end, it's all of the steps that go to make sure a heat pump or a solar PV system or a ventilation system, whatever, works efficiently, well and safely when the building's handed over.

So is it really a whole quality assurance scheme?

Really? That's a good way of summarizing it, Chris, thank you.

And for your thinking. Why now are we picking up on this in new ways? I mean, what's changing?

I mean, I think. Interesting. Years ago I did a thesis, it was actually on mechanical ventilation, heat recovery and the underperformance of those systems.

And that was 12 years ago. So we'd hoped to see a change now, but through that it became really clear some of the.

The lacks of communication, the lacks of checks that exist in the existing processes, particularly for complicated technologies.

So I think that's probably the key, that as we move towards complicated systems, complicated technologies, which we're seeing with the future home standard being rolled out more broadly, it becomes very important to run those quality checks by people who have a very strong understanding of what that should look like.

Okay.

I mean, and Ian, how are you seeing this commissioning stuff changing from your point of view as a person who's often involved in helping with commissioning work,.

Debbie's point, really, is that for all ventilation systems, really, an engineer needs to know what they're commissioning against and if they don't have availability to, you know, access to the design, then it makes their life quite difficult because there needs to be a defined ventilation strategy, a designed airflow rate, you know, room by room extract requirements, all of that understanding. And for ducted systems, you need to understand what the resistance is so you can set a fans efficiently.

Not just from a power point of view, but efficiently also from a resident's point of view, usually means from a noise point of view.

And that's the bit where I think there's still scope for improvement, because we're commissioning, strictly speaking, to Part F, which says measure flow rates, but we're not measuring the actual performance of the system. And I think that's where we need to move to. And it's not a difficult space to move into.

We've already got all the necessary tools to be able to do that. It's just maybe an additional process.

But the biggest thing that's missing is a feedback loop from the commissioning engineer, how the system's been set up back to the designer so they can go, ah, that system is set up exactly as I intended it and that can then be fed into future developments, future plots, even on the same development, and say, ah, actually we've had this feedback from commissioning that XYZ wasn't quite right, how can we improve that for the next phase? So I think things are going in the right direction, but room for improvement.

Obviously, Ian's talking through some of the process from the M and E side, but also when we're thinking about this there's contractors, there's house builders who are procuring electricity, mechanical contractors. They need to understand as far as they can, or we need to help people to learn what these systems need to look like, what they need to be.

The understanding, I think, at the back end of the systems that are being procured is really helpful. Otherwise it's very much left to the M and E contractors without a real ownership, I guess, of that from the house builder.

We're seeing that a little bit.

So some of the work we do is to try and do sort of bits of training or have difficult conversations around the technical side of things, or what the ventilation systems actually have, how they operate, what they look like more broadly.

So at the risk of putting words into people's mouths here and you can shoot me down in flames, what we're talking about is a quality assurance system with a feedback loop in where we're going.

We need to have a quality assured process from design, through purchasing, through training, through installation, through what I would have called commissioning, which is the checking at the end and then a feedback loop saying, how are we learning? How are we improving? Is that how you're seeing the whole world of commissioning now? Is that about right?

I mean, commissioning is commissioning. You're right, Chris. Commissioning, fundamentally, is that point at the end.

Well, I can tell that Ian's going to add something else that I've forgotten. What have I forgotten, Ian?

Well, it's not forgotten. I think what you've described is exactly how it sort of functions at the moment, or how it should function at the moment.

I mean, commissioning is more than just checking that it's working at the end, it's actually setting it up so that it does perform as designed. So commissioning is about adjusting things and, you know, tweaking flow rates and whatever to get it to be set up correctly.

However, the one point that we're starting to make now is to try and drive that feedback loop and to recognize that there are issues along this path between, you know, the gaps between design, installation, commissioning. Things happen on site that can then affect the commissioning process.

So what we're advocating for now is to help drive that feedback loop, is to have an extra step after commissioning and it's the validation step, and that is that someone comes in after it's been commissioned, before it's been handed over, just to have a sense check to say, actually, does this ventilation system meet the design? So that's where we're hoping to see a drive to improve that feedback loop.

Because if a validation check fails, for example, then that's going to go back to the home builder to make corrective action, which hopefully shouldn't be drastic. And until we're in that place, we're going to see some of the issues that we're currently seeing at the moment.

And can I just ask you both, really, I'll go Debbie first and then Ian. Do you see a distinction between - we talked about as built performance, but pre handover performance, where does post occupancy evaluation fit into this story of commissioning? Just briefly, Debbie, and then Ian.

I think it probably covers both. Obviously, for us, as the kind of development arm, we need to be learning how our buildings are performing and we need to be able to feed that back.

And if considerable issues come up through the BPE process that we find, then we'd be wanting to make them good with them, with the people that we're building our homes for us. So, yeah, I think it covers both of those sides of things. But you wouldn't need it for commissioning.

It's not kind of necessary in the same way that some of the other steps we've talked about are, I guess.

Yeah, I mean, Debbie's right. I mean, it's not a regulatory requirement to do poe for sure.

You know, it's hats off to developers like Ox Place that they are starting to consider a BPE or POE process post commissioning.

And I think one of the benefits that POE brings that commissioning can't do, it's obviously post occupancy, when residents have moved in, they're using their heating systems, they're using their ventilation systems.

That feedback is really critical now, certainly in the first year post occupancy, which probably from an evaluation point of view, isn't the optimum time because they're getting in to their new home, they're tweaking dials that they might don't understand.

So the systems like heat pumps and ventilation systems might not be optimal, but that is really critical still to do some evaluation in that first year window, especially because the property is under sort of a defects period as well. So if anything fundamental can be gleaned from that period.

So you might find speaking to residents, it doesn't have to be hard data, it can be speaking to residents, having surveys and semi structured interviews that you can find very valuable information. So, you know, is the ventilation system quiet enough? Is it too noisy, is it too dry in winter? Or, you know, is it too hot in summer?

And with heat pumps, you can find out, you know, is there a particular room that hasn't been balanced correctly? Is it too cold? How are you getting on with the thermostat?

And also for the hard data part of POE on that, you providing the infrastructures there, you can get data from the heat pumps so you can understand the efficiency, how well it's been set up during commissioning, and that then allows you, if you wish, to do some, I'll call it seasonal commissioning, because that's what people in the commissioning world understand. But Corrective action, you could say, just to make some tweaks to make things better. So I do think first year POE is actually quite valuable.

What does commissioning look like for different types of ventilation system and where do I go to find more information?

I'll repeat the point that I've been saying that there needs to be a design to commission against. So that's really important. That goes across every ventilation system.

Sticking with three basic forms of ventilation, we still have natural ventilation, we're moving more into continuous ventilation in new homes. But natural ventilation is still a significant part of the market. And with that system it's fairly simple. There's not really any adjustments to do.

So you're not really commissioning, you're simply testing the fan. The intermittent fan in the bathroom and the kitchen and so on are working and meeting the flow rate and recording that.

The one area that I find is often an issue with, with natural ventilations systems is having the right size background ventilators. And let's face it, the background ventilators are the important thing. They provide that 24 hour ventilation in the property.

So often they can be either the wrong size or in the wrong rooms or, you know, not enough of them. Sometimes there's too much of them, which isn't necessarily an issue because hey, residents can close them and they often do anyway.

So having extra capacity isn't necessarily a problem when we come to the continuous systems. I mean the commissioning is about the adjusting off the fan and setting up the system as a whole for the whole house ventilation.

Still, what I often find there that happens on systems, particularly MeV systems, whether it's centralized system or decentralized system, is that the fans are often only set to the individual extract rate rooms because that is a published value in approved document F. So a kitchen for example, should achieve at least 13 liters per second. A bathroom should achieve 8 liters per second. And that is what I find.

Like the commissioning sheets actually are set to how they've recorded those values and set the fans to those values.

But what's missing is the important bit, which is, you know, the background ventilation rate, because that is the 24/7 rate that's needed for the whole dwelling. And that often just gets missed out essentially.

And instead what a lot of commissioning engineers are doing are just setting it to the individual wet room rates, thinking that would be sufficient for the background rates and actually sometimes you need more. So we can find that homes are a little under ventilated when they're set up in commissioning.

Moving on to MVHR Systems, which is the most complex, if you like, but it's the same. But with the issue that you've now got supply air and the supply air needs to balance with the extract air.

And so as well as the issues of perhaps not having quite the right ventilation rates, what's more critical with a MVHR system is the balancing.

So if the system's slightly out of balance, it's leading on supply air, or even if it's leading on extract, you've paid a lot of money for a heat exchanger in that MVHR unit. You want to make sure as much air passes through that heat exchanger as possible, otherwise you're wasting money, essentially.

So if you're bypassing that by imbalancing the system, then that's an area that needs to be focused on, really.

And in terms of, I mean, if I'm a developer and I'm looking to find somebody who can commission for me when I, you know, purchasing the services of a commissioning engineer, I mean, how do I go about that and how do I make sure I've got somebody who's on all of these issues that you're talking about?

I'll plug the ventilation guide that the Future Homes Hub have just published. So Ventilation in New Homes, where to Start for Home Builders.

It's available on the website. I will say it's a great guide, but then I have a biased view being the author, but I think it's a fair guide.

It's a great guide!

I will say, but, you know, it's not me alone. Obviously there's a steering group and it's also taking the work from the ventiliation implementation group and bringing that into under one cover.

What we talk about there quite a lot is competence. That is essentially where home builders should be asking their subcontractors. And that subcontractor could be an M and E contractor.

The M and E contractor could be the designer for the ventilation system. There might be a separate designer, but that still comes under the main contract procurement. But they need to understand the competence requirements.

And what we advocate for in the guide is for a named designer, because that's where everything starts and everything should belong to that designer.

So I would say, however, we are in a bit of a transitional period right now, because where to go right now to point a home builder to a place where they can procure a competent designer is a bit of an unknown quantity.

There's not a single place I could say this is, you know, go to this website and look for a List of contracts that are registered here that doesn't exist yet. I'm hoping it will do in the future.

But what home builders do have is they've built up over the years is these relationships with preferred supply chain. I think it's just important, though, to start asking questions.

I would say the first thing they could ask for is to understand that it's not unreasonable for a house builder to expect that the person installing their heat pumps or the person installing their windows knows what they're doing. So they tend not to ask the questions, which might seem confrontational in some ways, to say to your contractor, but do you know what you're doing?

But I do think they should ask questions around basic competency and especially a way around that is to say, who is your designer?

Because we need to see a ventilation design and just looking at a manufacturer's set of layouts, you know, manufacturers are great at providing, if you like, I'll call it a free design. It's not. It's simply a drawing. Layouts of ducting and fans and equipment and a component list. But the design needs to be more than that.

And a manufacturer can't provide everything because they're not on site doing coordination and so on. So it needs to come from their installer / designer. That needs to be part of that process. So it's having those questions early on.

Brilliant. Thank you so much. Right, Debbie, I'm going to come talk to you about heat pumps.

There's a similar sort of sets of questions, but the heat pump world is slightly different, isn't it?

Because you often may get your heat pump designed for you by, say, by a manufacturer, but what does the whole system design for you by the manufacturer of the heat pump? But what does the commissioning process, what does that potentially look like?

I mean, just talking to that point about design, I mean, I'm not a specialist like Ian is in that level of detail. But we would expect the M and E contractor to be coming back with a design, whether it comes in part from the manufacturer or not.

It does need to be sort of with the relevant heat loss calculations, those kind of things that kind of set up specifically to the dwelling that we're looking at with commissioning.

Again, I've kind of got a sort of checklist of the things that we see when it comes through commissioning, but there's a lot of things that are fundamental to the performance of the heat pumps. So flow rates, temperatures, the pumps, system controls, looking at the weather, compensation, things like that.

All in all, what we're looking at is them commissioning something that meets what they say the coefficient of performance is that they've stated early on.

I think the other thing that we look at, we pull out in our energy quality assurance, as well as being things that are commissioned, it's looking at the siting of the units, things like the air circulation around the external unit, buffer vessels on the cylinder tank, how they're spec'd and how they're worked into it, condensation drains, sexy stuff like that, defrost cycles.

All those kind of things are things that we get looked at and we get checked over by people like Ian and our other energy quality assurance people at the commissioning stage and much earlier. So I think what we're seeing is a big jump from somebody setting up a gas boiler to somebody commissioning a fairly complex heating system. I think the other point is, obviously, with the heat pumps, you're looking at achieving that coefficient of performance.

The reason why we want them in is that they're not direct electric, that they're efficient.

So that's what we're really pushing to see - a design all the way through to commissioning that achieves an efficient product that will save our residents money in the long run, basically offer cheaper energy bills.

And with the heat pumps. So the commissioning's done by your M and E contractor?

Well, we commission a contractor, so we don't build ourselves, we commission house builders. So, yeah, it will be their M and E subcontractor. It'll probably be a subcontractor of the mechanical contractor.

Normally that's often the way it goes. So it's subcontracting.

So Ian's point about competence is really valid here, because we're at the top of the procurement chain. It may go down like three different routes to the person who's actually maybe designing and installing.

So the competence of that person is really vital.

So you're making that judgment on who to use based on the competence of the person of the organisation at the top of that supply pyramid and then seeing how that works out, because you're going to get feedback from the people living in the homes if any of that's going wrong. I see, yeah.

Well, we don't get to evaluate the competence at that level because the procurement process is.

There's a lot more things that come into the procurement process that kind of, I suppose, go ahead of that, but quality, obviously, being one of them, but not to that level of detail.

So we're very reliant on our employers requirements to set out what we require and what we need, and also our energy quality assurance process to go through and check that that is being met.

Because, you know, three steps down the line, we're not evaluating, or we don't have the power to evaluate who is contracted as installer or designer. We only have the power to comment and engage and push our house builders and their subcontractors to a standard that we would like to see.

So you can imagine there's a lot of difficult conversations there and we're very keen to sort of help engage and teach and learn with people along the way on that process. It's these new technologies as they come in, we're all learning.

So I think that we're at the top of the chain, but we are bringing in support and guidance from technical experts to check the people who were kind of maybe three or four bits down the tender chain, who were brought in to do the actual real work of commissioning and all the design work before that.

And, Debbie, I've noticed you've used the expression difficult conversations and Ian has also used the expression difficult conversations.

We have a lot of difficult conversations.

Do you think as a sector, we're a bit shy of those difficult conversations?

I don't. I've never been shy of those conversations and I don't know about Ian, but they're hard to have, aren't they?

You know, it's really important to have a positive relationship with your contractors and appreciate the work they're doing.

I think that's probably more the key phrase is - it's important conversations rather than hard conversations, and does not shy away from them.

So in my role, for example, as an energy QA for Ox Place, my role is sort of new to a lot of home builders.

And probably in the earlier sites that I was involved with, there wasn't really an understanding of what my role was, because, you know, there's the client role, there's the building control role, there's the clock of works role that I explace, employ. And so my role is, well, who's this other guy who's checking our stuff?

And so there were some important conversations to be had with the builders about that role.

And as we're seeing sites now sort of progressing and the same contract are being appointed onto the next sites, they're starting to understand what the energy QA role is. And actually, we've had two different types of relationships, really. We've got some who are kind of maybe a little bit still.

Well, we'll just do things the way we always have and deal with building control and the clerk of works and the client and the energy. QA role is more background.

But there's been others where it's been really positive, I would say, where the home builders said, you know, oh, gosh, you've caught us out on a few things we didn't quite get right, but I'm really pleased.

That's what Ian and I love hearing people saying, how can we learn more? How can we do this right next time?

Absolutely. So now we're providing training courses for those builders on things like airtightness, on ventilation and whatever. And those are being developed so that we can go right at the beginning, at the first design team meeting, say, this is what our role is.

This is what we're looking at. These.

We've already done a critique on maybe some of the early design stage drawings and the feedback is really positive because they're starting to get that. Actually, if we get this right at the beginning, our life's going to be a lot easier at the end.

Well, it's not been a difficult conversation, it's been a fascinating conversation, I just want to say!

Before we go, I just like to grant some wishes. I don't have the power to grant you three wishes, I can only grant you one wish each, which is. And what is it that you would wish for people to take away from this podcast? What's the one key message you think? Think would be great?

I'll start with Ian and I'll go to Debbie.

I think a short answer for that is focusing on ventilation, is that ventilation is a whole dwelling system. It's not just a fan.

And I think if we move away from that mentality and start thinking about the whole dwelling, the air intake, the cross flow through the dwelling and then through the fan, you know, at the end, that. That is what I would like to get across, is that think about the whole. The building ventilated system, the fan is just part of that.

Okay, Debbie?

Yeah, I had to think about this one.

I think for house builders, who I assume are kind of normally our audience, it would be really to encourage them to fully understand the systems that they're procuring. The ventilation, the heat pumps, whatever, seek out CPD on it.

Look into these systems in a bit more detail so they can understand what good quality, what compliance and what good design looks like.

Ian, Debbie, it's been a real treat. Thank you so much. Thanks for joining us on the Future Homes Podcast and I look forward to seeing you again soon. Thanks a lot.

Thanks Chris. Thanks Ian.

Thank you very much.

Thanks for listening to this episode of the Future Homes Podcast, and thanks once again to Debbie and Ian.

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