Webinar on the Decarbonisation of Heating

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And good afternoon everyone.

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Welcome to our session, which will cover carbon reduction options for churches
using oil for heating.

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My name is Amad Kayani, I'm a building services engineer within the technical conservation teams at Historic England. and I typically get involved in work
relating to some of our applied research that looks into energy systems
and heritage contexts. And I've also worked on climate change adaptation of buildings, specifically looking at overheating.

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I'm really pleased to say that I'm joined by my colleague Dan MacNaughton today.

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Yes. Good afternoon, everybody.

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I'm Dan McNaughton.

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I'm a senior engineer at Historic England. And when I found out that I was going to be doing this research, looking into carbon reduction options,
the church is using oil for heating. I was really pleased because this combines
my main interests in experience, some design, lots of heating systems, some of them in churches.

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My background is in sustainability,
engineering and working with historic buildings. So a good match, really.

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And before we go any further, I just want
to thank you all for joining us today.

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There's been a lot of interest in this webinar and the last one that our team did
in December on heat pumps. And your support is really appreciated.

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Absolutely.

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So moving on.

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Why do we need to act now?

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Well, I want to start by setting the scene
for this research. And it's fair to say that climate change is quite rightly grabbing most people's attention.

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I find it quite sobering, actually when you consider the impacts that we're already observing, both within our own shores and internationally.

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We've already seen the impacts of things like extreme heat waves, high rainfall and coastal erosion, which is really challenging our perception of what normal looks like and what the future might look like.

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So this work, which is to do with low carbon heating options, aims to reduce carbon emissions and therefore help mitigate potentially disastrous climate outcomes.

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And it is really heartening to see that this event is so well attended. I think we will have around 500 people that's signed up,
so we're really pleased to see it.

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So well attended.

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And it really, you know, provides us with a lot of encouragement and opportunity for shared learning towards more sustainable outcomes for heritage.

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Before we move on, I want to get you all involved now with our first interactive poll, and we'd like to know which low carbon technology has been employed
most widely in historic church buildings.

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Yeah, and as you see,
there's a lot of engagement already,

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but your options are air source, heat pumps, biomass. Ground source heat pumps or photovoltaic solar panels.

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Interesting to see that photovoltaics have taken the lead with air source heat pumps closely behind. And not many going for ground source
heat pumps yet.

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But yeah, much fewer. Um.

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Interesting.

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So just give people a minute, minute more
just to have a think about that and respond.

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so based on the information
that we actually have from C of E, we're aware of 15 biomass installations
in historic buildings, 21 ground source, heat pump installations,
32 air source, heat pumps, installations.

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However, the correct answer was actually photovoltaics. And there's 118 installation. In grade one, grade two store and grade two listed church buildings.

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Well, so why is this research important?

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Well, quite commendably, the Church of England has been very ambitious in setting new targets for all part of the church to be net zero by 2030. And this target is very fast approaching and it's only really seven years away. And it really highlights the scale of the challenge.

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But to illustrate this further, using the example of a Grade one listed church, the annual carbon emissions were around 3000 kilograms for oil and just 67 kilograms for electricity use on site.

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So the overwhelming majority of emissions stemmed from oil consumption and therein lies the problem, but also the opportunity because across all of the churches it was found on average the oil consumption actually accounted
for 94% of the total emissions. In these case studies, the oil consumption was all used to generate energy for the heating system.

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And this really gave us a lot of reassurance. And I hope that you'll agree that this research was tackling the biggest challenge that churches have in reaching net zero carbon, and that has the biggest potential to make a positive impact on reducing the carbon footprint.

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So as well as the clear environmental drivers for this research, the unexpected issue, if you like, that arose during the course of this research was the increase in fuel prices that we've seen.

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The price of heating oil has increased from $0.43 per litrein December 2020 to $0.83 per litre this month. The price actually peaked around £1 per litre, but it hasn't been quite as volatile as natural gas over the past 12 months. And this highlights the ongoing tensions between energy affordability, energy security and carbon emissions, also referred to as the 'energy trilemma'.

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And we might, you know, often hear about this at a national scale. But what's really interesting is how changes in global energy supply chains can trickle down and impact communities on the ground and also impact how we assess what carbon reduction options are viable for particular sites. One of the really great things about this research was having the opportunity to visit some amazing places and directly engage with communities and being part of that discussion on the ground.

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The churches that formed part of this study are located in the Cotswolds area of outstanding natural beauty, which is a central area of England, certainly very picturesque, and we were very fortunate to be serving such beautiful locations.

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I'm going to run through the churches that we surveyed.

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And the first is Church A this is a grade one listed Anglo-Saxon church built around the 11th century and comprises of a single church building. And there's several listed monuments within the church yard.

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Within the church yard  what was also was really interesting is that this church has no mains water, no mains water supply. And from this you can already appreciate some of the unique limitations for different sites that might constrain possible heating options.

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Yes, one of the big mysteries about this site was that I knew that it had a hydraulic or wet heating system with radiators, but I was also told that there was no mains water supply at the church.

What puzzled me is that it's not possible to have a hydraulic heating system like this without a mains water supply
to pressurise the water.

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So what I found during my survey was a feed in expansion tank at high level in the vestry, and I looked everywhere for a water connection to the tank,
but there just wasn't one. So I asked the church how they put this tank and was really surprised to hear that they do this manually. Using the watering can is located in the church out for water in plants.

Now this mains water supply in the churchyard is nowhere near the church building. But what they did show me was that all of the existing heating components are at risk of corrosion from air ingress, and this can also cause significant damage to components such as pumps.

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Now, the cost of bringing in a new water main for this church to the church building was in the order of £10,000. So it is easy to appreciate how this could
impact the financial viability of any heating system with pipework and radiators.

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Absolutely.

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Church B is a grade two star listed church dating back to the 13th century.

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Like church, this also has several designated monuments in the churchyard, which also includes a specific scheduled monument which is pictured
to the right of the church.

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The church is currently heated with oil and only has a single phase electricity supply, much like what we've already seen.

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Church C is a grade two listed church built around the 19th century,
which is also heated with oil and only served with a single phase electricity supply.

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What the picture on the right demonstrates quite well is that it's quite a large area around the church and it sits on these large grounds.

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However, what we quickly realised was that using this for any renewable generation would not be possible due to the various grave sites
that you could see in the image.

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Finally, Church D is a grade one listed church and comprises of an 11th century building itself. It's 11th century and also comprised of a nearby church school which was constructed much later.

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These buildings have individual three phase electricity supplies and mains, cold water. And the reason why it's important to highlight this is that sometimes larger plant equipment can necessitate upgrading the electricity supply, which can have cost implications.

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So moving on from the individual churches, I want to talk a little bit about the technology appraisal process and developing a robust appraisal
was based on this process that you can see where each step was informed by the next and this was applied for each of the case study churches
for both consistency and rigour.

And this process really started with the people using the buildings.

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The first step was sending out a pre-survey questionnaire to really get to grips with the user needs and what the priorities were on the ground.

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Once we had this information, we could go and visit the various sites to try and understand the physical constraints that we were working with, but also recognising the importance of sizing systems correctly and not assuming that legacy building services could simply be swapped out. Like for like in terms of size, we looked into heat loss calculations on paper to inform what then went
into the technological appraisal once we were sure of the actual heating demand and finally we were able to present the outcomes
back to the users to close the loop.

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And I'm now going to pass over to Dan, who's going to speak specifically
about each step of this process and how this informed our methodology and the conclusions that we ultimately came to think. Smart.

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So a key part of this project was visiting the sites to understand more about the historic buildings, the existing heating system and the external site.

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It was possible to approach these surveys with an open mind as there was no prior knowledge of the buildings other than some written feedback from the end users about the performance of the existing heating system and the future aspirations.

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As the market has just mentioned, we issued a pre-survey questionnaire with 13 specific questions
to improve our understanding, and this captured information, which proved to be essential to the recommendations regarding how and when the building was used.

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So I'm not going to go through every site
that are visited in detail, but instead I'm going to pick out one of the locations
and look at it in greater depth.

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This amount is already mentioned.

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This case study is a grade two listed church dating back to the 19 century. It's located in a conservation area and the yellow area on the plan shows the extent of the churchyard and on this particular site there isn't any land that is suitable and available for renewable technologies.

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The church is currently heated by an oil fire boiler, which heats all areas of the church using column radiators.

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And now all of the churches that I visited, this one had the most positive feedback
about the performance of the existing heating system and the level of thermal comfort achieved. And it's worthwhile making a mental note to remember that the existing heating system works well because this has some influence on the recommendations that you'll see in a minute.

So we're very fortunate actually to have this. But the Matterport camera that we have at Historic England allows you to carry out very detailed internal surveys, and we use this during our surveys of the churches.

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And are you able to bring in the video for this one?

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Perfect.

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There we go.

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So it's a really useful tool for revisiting surveys, and you can take accurate measurements
of the church. And these measurements are to within one or two percent accurate. You will see if the space or the building services that once we've created this digital model, we're able to store this
the survey online.

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And what has been quite nice is being able to share these with the churches, which has allowed them to showcase the buildings which they know so well. And another thing I like with this survey tool is you can zoom into areas of the church to look at things in more detail, and you've probably noticed that the video isn't the smoothest. That is because of controlling the movement using the circle cursor, and it's a mechanical design engineer.

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You can easily measure the size of the existing heat emitters, which is really useful when you're estimating
how much heat output they can provide.

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So the real value of the Matterport survey was in overcoming the poor quality of the existing record drawings for the buildings where these were available, they were limited to lay out plans, which went to scale.

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So in order for us to be able to carry out heat loss calculations, it was necessary to use the key building
dimensions. And this was definitely enhanced by the use of the Matterport camera.

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Absolutely.

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I would just echo that and say that even in some of the other work that I was doing around overheating, it's been a really useful tool in capturing not only the, you know, the physical dimensions of the building,
but also how the building is being used at that moment in time by the occupants.

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So absolutely a very important tool for us.

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Excellent.

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So after completing most of the research, one of the things that I wanted to do was to carry out a detailed heat loss calculation for one of the churches for the recommendations. I had used, estimate heat
loss calculations, and I wanted to justify that decision. So what I found out was that my quick engineering estimate resulted in a design heat loss of 65.2 kilowatts, and my detailed heat loss calculations, which took more time, resulted in a design heat loss of 63.2 kilowatts. So I was very happy that my engineering
estimates were accurate.

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Now, the other reason for wanting to understand the proportion of the different heat losses is that one of the churches that was surveyed had been advised already that most of the heat is lost through the roof in the windows. They were advised to insulate the roof and provide secondary glazing to the windows.

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At the time I advised them that you need to understand how the heat is being lost to the sphere before making these decisions and I wanted some data to support this.

So in addition to the physical fabric components that are visible to us, such as windows and walls, there are infiltration, heat losses and infiltration is the air leakage through cracks and gaps in the building envelope.

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And I had to make some simplifying assumptions about the fabric properties to allow this calculation to be performed.

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So in this example, glazing only accounts for about 8% of the total heat loss,
and the roof counts for around 28%.

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As you can see from the chart, infiltration is the most significant heat loss that is observed at this church. And you could spend a lot of time and money improving the thermal properties of the glazing, but then only be having a positive effect in reducing just 7.7% of the overall heat
loss.

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Clearly the form and the proportion of the fabric components will vary for every church,
which is why a detailed heat loss calculation should always be carried out by a competent person.

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In addition to appraising the thermal properties of any proposed fabric improvement, it is also essential to consider any impact to the aesthetics, the historical significance and the moisture performance of any historic building.

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So these are the practical heating technology options that have the potential to help us to achieve low or zero carbon.

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I'm not going to explain what these technologies are or how they work, but if there is something
that you are unsure about, then please feel free to ask any questions.

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So normally when someone presents help and all of the information and then conclude I'm
going to slightly change things around so that you can think about what I say
next before I go into detail.

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So I found out that there was no single heating solution that work best for all churches, and the solution depends on the church site, the physical form of the church,
and the operation of the church.

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The challenging reality is that it does cost money, but as an engineer, I can say that it is technically possible
to heat churches with low and zero carbon heating systems, and from a heritage perspective, it is possible to achieve this without adversely affecting the character and significance of these listed churches.

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So before carrying out detailed calculations for every possible option I carried out this assessment of the technologies to first consider the suitability of the site for them.

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This was a level where I just considered if it was technically and practically possible to install a certain technology.

Some of you may have noticed already that in addition to assessing the heating technologies, I also considered photovoltaics, hydro electricity, tea and wind power.

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So the technologies that could work for this site: air source, heat pumps, biomass electric boilers and electric heating.

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Then would you please be able to just clarify the difference between an electric boiler and electricheating for the audience, please?

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Yeah, I think that's a good point because it's something we get asked quite a lot.

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So I think the easiest way to consider the difference of is to recognise electric heating as local emitters
which have electrical supplies. These come in all sorts of form, but they were often wall mounted like radiators. But it's also possible to have electric fan compactors and even electric underfloor heating. But on the other hand, an electric boiler is very similar to a gas boiler, except that the gas supply
pipe and flue obviously not required, but of course it will need an electrical power supply.

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Now the electric boiler will also have hydraulic pipe connection so that it can connect to the heating system pipework in exactly the same way as a gas boiler does.

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So hopefully that clarifies things a little bit.

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So moving on with a viability assessment, those technologies that may work, bio, LPG and photovoltaics with bio the lowest carbon fuel that any supplier could provide to this church was a blend of 40 to 60%, which means 40% bio LPG blended with 60% LPG. This blend of fuel does lower the carbon emissions, so it's great in that respect, but this won't help the church get close to net zero.

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The reason that this may change in the future is that there is a commitment within the supply  industry for 100% bio LPT to be available by the year 2040. And personally, I think that well could be a useful bridging option, particularly for rural locations as the UK works towards its 2050 net zero carbon target with photovoltaics, there wasn't any land available at this site for an array to be installed
at ground level, but a roof installation could be possible, subject to a detailed study, structural assessment and survey being carried out and a faculty being obtained.

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There was one church in this research that did have land available, so I did carry out a photovoltaic feasibility study at that site and then the technologies that weren't
suitable for this site with ground source, heat pumps, hydro electricity,
water source, heat pumps and wind power.

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So it's time to get you involved again.

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Actually, the audience and we would really like to know before we go any further, what you think are the most important factors to consider when comparing heating technology options?

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That's right.

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And what would work really well is if you could just enter a single keyword

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and we'll use this to generate a word cloud of your ideas.

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We did something similar to this in a face to face interactive workshop at the future of Heating Conference last June, and we had some really well
considered ideas.

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So interesting to see immediately that cost is quite a large, quite a popular word.

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Just give that a moment to refresh
is changing very quickly, isn't it?

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Absolutely, yes.

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Sustainability features in have really their brilliant.

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Yeah. Is refreshing quite a lot.

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I think what it does highlight is that how tricky it can be when developing an an appraisal process for different types of technologies because there are so many different
considerations that would actually vary depending on, you know, specifics of the site.

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And maybe if we bring that to a close, have a quick look.

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Wow. Oh,

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yeah.

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Efficiency, appearance, aesthetics.

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Oh, great ideas there.

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Even even those that have embodied energy
there as well.

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Space is one absolutely,

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really important one.

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We will capture any anyway.

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We capture that just just for our records
as well because it's always good to hear from the audience as well.

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Brilliant.

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Payback time. Yeah, that's fantastic.

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Thank you for that.

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We are keen to move on now.

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Perfect.

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So this heating technology comparison summarises all of the calculations that I've done to estimate the annual carbon dioxide emissions, the annual fuel costs and the capital cost for this case study, the baseline is the first row on the top left, which is the existing 59 kilowatt oil fired boiler which currently uses £1,764 of fuel power and has annual carbon dioxide emissions of over 5000 kilograms.

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Now, the first thing that I want to point out in this comparison is that although I've calculated emissions data for the air source, heat pumps, electric boiler and electric heating options, these emissions
could all potentially be zero if a green electricity supply tariff is available.

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And on the financial side of things we have running costs varying from £1,216 right up to just over £5,000 per year.

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So big difference there, depending on what option you go for.

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And then there is a lot of information
regarding the capital costs, as I've included options to retain the existing heating system for the biomass and electric boiler proposals. What I mean by that is retaining the existing heat emitters and distribution pipework.

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And the row on the bottom right of this comparison shows what can be achieved if we provide local electric heating in the form of a pure heat to install to every PUE.

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This option won't provide the same amount of heat or the same level of thermal comfort
as the other options. But this does offer an alternative approach.

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So before we share our recommendations, it would be really good to hear your thoughts.

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And our question is based on the data that you can see that will remain on the screen, what would be your
preferred heating technology?

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Thank you very much for bringing that up.

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And your options are air source heat pumps, biomass, electric boiler and electric heating.

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I will say as well, while while you're thinking about this, because we've run this exercise before in person,
an interactive workshop, I would stress that it's not really a right or wrong answer to this.

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It's more to understand your ideas because different churches have different priorities.

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And as with everything, there's a lot of different things to consider.

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You may be restricted by your capital budget or you may have low carbon emission ambitions.

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So lots to think about.

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It's interesting that air source heat pumps and biomass are in the lead.

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Yeah, interesting.

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Very similar for the electric boiler in electric heating.

00:27:36:06 - 00:27:40:03
That's that's understandable because we've perhaps put the running costs as identical for those.

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Okay. I think we'll leave it there.

00:27:48:11 - 00:27:52:16
So what we've got, we got round about 34% of you said air source heat pumps, 43% have gone for biomass, 8% electric boilers and a few more actually now 14% going for electric heating.

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So yeah, I can understand why you went for those.

00:28:05:16 - 00:28:11:18
So now what I would do is I'll say what our recommendations were, but I'll talk you through that and
and explain it as well.

00:28:17:05 - 00:28:21:08
So for us, biomass sort of agreed with the audience.

00:28:21:08 - 00:28:23:10
There was the recommended heating solution as it provides a route to low carbon
emissions.

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Electric heating and electric boilers are also feasible and should also be considered
as they have the potential to achieve zero carbon emissions.

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The advantages of biomass are that it has the lowest fuel costs.

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It is compatible with the existing heating system, which we know works well and it's the lowest capital cost
for providing heating.

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If the existing heat emitters and distribution pipework are retained.

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The advantages of electric heating and electric boilers are that as the grid decarbonize this
this proposal will allow the church to be net zero carbon by 2050 or sooner if a green electricity tariff
is available.

00:29:08:20 - 00:29:11:18
The running costs of around £5,000 per year is the main drawback of the electric heating and electric boiler options.

00:29:16:08 - 00:29:20:16
And the estimated capital cost of electric heating would provide a brand new heating system.

00:29:22:06 - 00:29:24:12
There were no onsite emissions.

00:29:24:12 - 00:29:26:23
So when you look at high electric running costs of electrical systems,
it's always sensible to think about air source heat pumps
so they can be a really efficient way of using electricity.

00:29:35:04 - 00:29:39:07
But what we found for this anyway is that they're very expensive for this church
in comparison to the other heating technologies at nearly £100,000.

00:29:45:17 - 00:29:49:16
This technology does not achieve financial payback at this site within the expected life of the plant
when compared with electric heating.

00:29:54:20 - 00:29:56:10
But you'll see see in a minute.

00:29:56:10 - 00:29:58:21
And the ANOVA site.

00:29:58:21 - 00:30:02:22
So source heat pumps work very well and actually are the preferred option.

00:30:04:09 - 00:30:07:07
Now, the lowest counter cost option is to just replace the existing heating plant with an electric boiler. So that might be something you'd do if you had a very limited budget comparing this option with a new biomass boiler while still retaining the rest of the existing heating system.

00:30:21:20 - 00:30:26:20
The simplified paper model, which doesn't consider inflation or future fuel costs, shows payback for a biomass boiler in seven and a half years, the expected working life of well-maintained
biomass plant is 20 years.

00:30:35:23 - 00:30:39:12
Therefore, over the longer term, this is the most financially viable heating option.

00:30:42:02 - 00:30:43:11
I think what this really does show is it kind of highlights the practical implications of delivering net zero on the ground.

00:30:51:17 - 00:30:53:22
Occasionally we do see net zero strategies that can be a bit disjointed from what the reality is for a community.

00:30:58:05 - 00:31:00:21
The reality is for a particular building or group of buildings.

00:31:01:09 - 00:31:06:09
But what I think this work captures quite well is how to arrive at a solution that is part of the way and working towards that solution from the bottom up.

00:31:17:19 - 00:31:21:13
So to conclude, the key observation is that no single heating technology is recommended for either
all of the buildings or each building type.

00:31:27:12 - 00:31:31:02
There is an even split in this small sample of historic buildings between associate pumps, biomass
and electric heating being favored.

00:31:37:05 - 00:31:38:08
This highlights the need to carry out a detailed technical feasibility study at the early concepts stage of a project involved in the replacement of a heating system in a historic building.

00:31:48:21 - 00:31:53:03
The recommended heating technology was found to be influenced by many factors, including the building, site and location, the size and form of the buildings, the use and operation of the buildings, the condition of the existing heating system and the existing utility infrastructure.

00:32:05:20 - 00:32:08:13
So lots to consider there. Surprisingly, it was found that the estimated costs and the recommended technology was not significantly influenced by the type and capacity of the existing electrical supply. Although we do need to stress that it's just for this small sample of churches, which is why I was surprised that the existing utility infrastructure that did affect the recommendations was the one we've already mentioned where one church church did not have an existing water supply.

00:32:38:07 - 00:32:41:16
From a technical perspective, a good design engineer always aims for the most efficient use of any fuel and heat pumps provide a solution which uses electricity effectively to generate heat.

00:32:51:21 - 00:32:53:07
The factor which prevent it. Air source heat pumps being recommended for some of the churches was the high capital cost of the plan.

00:32:59:07 - 00:33:03:10
I'm hoping that as the market for heat pumps in the UK develops, the cost of this technology will become more competitive as this will help heat pumps to be financially viable.

00:33:10:02 - 00:33:13:13
In more case studies already in the past year, I've seen that the major boiler manufacturers
are starting to offer heat pumps for sale, which is a strong indication of the direction that they see the heating market heading towards.

00:33:23:16 - 00:33:27:16
The increase in fuel prices will also favour the viability of heat pumps.

00:33:28:13 - 00:33:31:23
The factor which resulted in a source heat pumps being recommended for the Church D was the regular use of the church throughout the week and the consequential high existing energy consumption.

00:33:41:13 - 00:33:45:06
Biomass would have been viable on most sites if the boiler room and flue location could be established, that would not adversely impact local air quality.

00:33:51:07 - 00:33:53:06
But overarching all of this what I'm really pleased about is that all of the historic buildings investigated have the potential to be net zero carbon, and none of the recommended heating technologies present a significant risk to heritage.

00:34:08:07 - 00:34:10:18
Well, thank you very much for joining us today. We've hope you've found it useful.

00:34:13:23 - 00:34:16:22
The work that we've spoken about today is in the process of being published and it will be available
on our website very soon for free access.