- We're recording this episode in the summer. Which you'd think would be a strange time to discuss home heating. However this is a British summer, which means blistering temperatures one day, and then blaming cold, wind, and rain the next. Indeed the mercury reached 28.6 degrees C in West London a couple of weeks ago, and now there are loads of flood alerts from heavy storms.

And this is of course being experienced all around the world. Just look at the recent heat waves in Canada. Elsewhere there is increased sea ice loss and sea level rise, and where animals and plants are living on the planet is shifting. Climate scientists are warning that these dramatic weather shifts and extreme weather events are happening more and more often. And that we've got continued rapid climate change to thank for it. So what can we do about it?

Well that's what the first season of this podcast is all about. I'm trying to find out what I can do to have a real echo effect. And this week I'm looking at the fuels and technologies promising to make the way we heat our homes more sustainable. We haven't resorted to putting the heating on home recently, but the boiler doesn't get the summer off. Every time we turn on the hot tap or have a shower it fires up.

Burning natural gas, a fossil fuel, every time contributing to the greenhouse gases that are perpetuating this rapid climate change. And I'm not alone here. Behind the times with a planet poisoning boiler, a 2019 white paper released by the government called Powering Our Net zero Future, said that 90% of homes in England use fossil fuels for heating, cooking, and hot water. So again, what can we do about it? Well there are plenty of options, including one you may have heard of. I'm Greg Foote. And today's Which investigates asks, will hydrogen soon be heating your home?

Which investigates is a new podcast from the UK's consumer champion. We work to make life simpler, fairer, and safer for everyone. Then our mission for this podcast is simple, find out the facts and see who's actually delivering on the promises we see on packaging in the press or shared on social media. Our first season is focusing on claims of sustainability from plant based plastic free Eco-travel to electric cars. I'll be figuring out what genuinely reduces our environmental footprint and what is simply green-washing? Coming up, I learned the real impact of heating our homes.

- So homes and heating are responsible for around a fifth of the UK's emissions, which is a significant amount obviously. And a lot of people don't tend to realise that.

- I discover some ingenious solutions being used right now to cut our carbon footprint.

- This one in North London that runs from waste heat from the London underground. So they can use heat and energy from all sorts of different sources, and they then basically pipe hot water to all the buildings that need them.

- And we go overseas to hear how one country is leading the way when it comes to decarbonizing their energy.

- Have you ever had natural gas or an oil based, a fossil fuel based system in Norway?

- Households say no.

- Let's start with a personal question. Where do you keep yours? Some people have theirs in the cupboard, in the bedroom, or under the stairs, or in the loft. My boiler however is in the kitchen and I don't really think about it. I guess unless it stops firing or even worse breaks down, which according to one Which article I read from a few years ago happens to around a fifth of UK homes each year.

Now it may not come as a surprise if I say I'm not an expert on boilers, or home heating in general, for that matter. But here at which we seem to have someone in the know about any product, or tech, or area, that you may want to know more about.

- My name's Karen Lawrence. I'm a senior researcher and writer at Which specialising in sustainability.

- You'll hear from Karen a lot in this episode. She is a font of knowledge on home heating. And one of my first questions to her was how many of the 26 million or so boilers across the UK use fossil fuels?

- Well in terms of the UK as a whole, it's about 85% of UK homes that use natural gas, mainly methane. That's around 22, 23 million customers or so something like that. We also have about another 5% use heating oil for their homes, which is also obviously a fossil fuel and not good for the environment. And the remainder is a mix of sort of electricity and other methods.

- Early this season we explored the impact the internal combustion engine vehicles are having on the environment with Oxford Professor Tim Schwann and telling me that they make up a quarter of all emissions. So how do these fossil fuel boilers stack up?

- So homes and heating are responsible for around a fifth of the UK's emissions, which is a significant amount obviously, and a lot of people don't tend to realise that. When you use energy in your home you don't really see anything, and you don't really see anything sort of being smoked like you might do in a big factory. And within our homes it's specifically our gas boilers that are a major problem.

- That's Jess Ralstone. Another expert you'll be hearing plenty from in this episode.

- I'm an analyst at the ECIU, which is the Energy and Climate Intelligence Unit.

- Before we hear more from Jess and discuss the potential or not of hydrogen, of heat pumps, and of other alternatives, let's just take a couple of minutes to understand how did we get here. Why are we now apparently so reliant on fossil fuels to heat our homes?

- It's from around the 60s and 70s when we started to discover natural gas in the North Sea mainly. Our homes before that were heated by a different sort of gas called coal gas or town gas which was produced from coal, which was an even dirtier form of fuel for our heating. Producing even more carbon emissions and lots of air pollution. But once natural gas was discovered that was a much cheaper and cleaner form of heating.

- I don't know about you, but my main memories of the North Sea consist of Chile beach holidays and the likes of skegness, and great Yarmouth, eating an ice cream as the wind blows horizontally across the sea front. But away from the shore, Europe's exploration of the 750,000 kilometres squared of the North Sea has been a source of intrigue and controversy for decades as producer Rob reports. [music playing]

- Long dismissed by many as a potential source of oil or gas. Over the last four decades the North Sea has become the centre of one of the world's most productive energy industries. Gas was first found in quantity in the Netherlands in 1959, followed a few years later by the first British discovery of gas off the coast of East Anglia. The British industry grew rapidly partly because the deepening economic crisis in the UK meant that there was enormous pressure on the industry to get gas. And later oil flowing.

As exploration moved further North, more and more oil was found. In 1975, a small entrepreneurial American company brought it to shore for the first time. And by the early 1980s with more British European and American companies laying claim to sectors of the North Sea, there were soon over 100 rigs.

Britain quickly became a net exporter of oil, and by the 1990s of gas too. Nowadays the North Sea supply is on a slow decline but ever more sophisticated technology means that significant amounts of oil and gas can still be drawn for anything up to 50 years. And we've now cast our eyes beyond the North Sea. Thanks to recent discoveries in the Atlantic Ocean, there's a well-established industry of the West of Shetland too.

- Really interesting raptis for that, and thanks to the University of Aberdeen for allowing us to use their resources to take a little look back through the history. Now though, it's 2021. Over 60 years since natural gas was found and we are still pumping it into our homes. One day the oil and gas will run out, that's why we call it a non-renewable source. But while we use it it's continuing to release greenhouse gases that are accelerating global warming. So we have to focus our attention on cleaner, more sustainable methods to heat and power our homes.

- One of the options for decarbonizing our hands is a technology called a heat pump. And a heat pump is a little bit different to a gas boiler in that it uses electricity to create heat in our homes rather than a fossil fuel natural gas. And that is obviously really good because it really reduces the greenhouse gas emissions because electricity is much cleaner than gas.

- This was something I touched on in our episode on electric vehicles, when I was looking at where our electricity actually comes from. We heard how last year 2020 was the first time renewables generated more electricity than fossil fuels. Windy conditions last spring meant that renewable generation reached record levels, and contributed almost 43% of electricity generation compared to under 40% coming from fossil fuels. Compare that to the figures from 2008 where we got 75% from fossil fuels.

- I think wind and solar will play a really important role in cleaning up our electricity, if we do have a rapid ramp up of heat pumps. That'll be really important in providing the electricity to meet that demand.

- So what do heat pumps look like, and how do they work?

- Heat pumps obviously vary in size and you need a bigger one, the bigger the building is that you need to heat. So it sits outside your house. And they vary from the size of sort of maybe like a very large suitcase up to more like a fridge, and it can take heat from the air and condense it and put warmer air into your home to heat it. It can actually take heat from air, or from the ground, or from water In fact, any source of heat. And it doesn't have to be particularly hot, it can actually be below zero.

It can still extract heat from the air and condense it, make it warm enough to actually heat your home. I know that sounds a bit bonkers but they use them quite a lot in countries that are much colder than ours. So places like Norway have a lot of heat pumps as it goes, and they can use them even in the winter to warm their homes.

- I think this is the first chance I've had on this podcast to press the Norway Claxton. I mean the Scandinavians. They just get it right, don't they? So no surprise that Karen has chosen them as a potential vision of our heat pump filled future.

- That is the Norway Claxton.

- Where are you right now?

- I'm in my office in Trancham. It's 550 kilometres North from Oslo.

- Is it as beautiful as I'm picturing that area?

- I don't want to compare us with Italy, but it's very romantic in some way.

- Norway just always comes up at the top of almost every list, doesn't it? Happiest place, healthiest place, is it that wonderful to live in?

- If you think walking to job and biking to job is very good, and of course no big pollution.

- This is Natasha Nor.

- My name is Natasha Nor. Professor at Regent University of science and technology, department of energy and process engineering. There is something very special that you should know about Norway. I think now it's 100 are more than 100 years ago when they found out that Norway is very rich of hydro-power.

- Have you ever had natural gas or an oil based fossil fuel based system in Norway?

- Households say no. Maybe some farms, but usually they are using wood or electricity. But households never.

- Natasha told me that 20% one in five of Norway region households have heat pumps in their homes, with many of the others being heated by waste from industry. Something I'm going to come back to later in fact. And I was interested in the numbers around how heat pumps compare against other alternatives.

- Electric heating generally is 100% efficient. So it converts 100% of the energy into heat. A gas boiler is around about 90% efficient. A heat pump is something like 300, 350% efficient. It actually produces far more heat, 3 1/2 times more heat than the energy that you put into it.

- 350% efficient?

- So, yes they run on electricity. But they are very efficient with that electricity.

- OK. That's enough on heat pumps for now. I'm going to come back to the costs of them later though, and also what you need to do before you consider a heat pump or indeed any of these alternatives. That's later though. For now let's turn to the title contender, as in the contender mentioned in the episode title hydrogen.

- Hello I'm Stella Matthews. And I'm hydrogen development manager at Northern gas networks.

- Stella is one of many overseeing a trial in Gateshead called simply the hydrogen home, with the aim of showing how useful hydrogen could be to decarbonize the home of the future. And in this case, rather than a gas boiler a hydrogen boiler is installed.

- The hydrogen home is in essence a showcase her Maharashtra home, which is going to be installed with hydrogen appliances, it will run on hydrogen boilers, it also features hydrogen cookers, hydrogen Hobbes, and hydrogen fires. And it's there for people to come along and look at the hydrogen appliance to see how normal they are see how they work, and feel exactly like your natural gas appliances.

The actual assets that we have in the ground that transport natural gas to your home can actually transport hydrogen with no queries of that at all. It will be a case of having hydrogen appliances installed into your homes, and then an engineer come in and just check in that they can be hooked up to the hydrogen if you like.

- But could we switch the entire country from natural gas to hydrogen gas? Well we have done something similar before. When the UK moved from coal generated gas to the natural gas mined under the North Sea, a government directed nationwide campaign saw the conversion of millions of household gas supplies. It started in 1968. And it took just eight years to change a whole system from one fuel to another. It involved converting 40 million appliances for 14 million mostly residential customers, reaching a peak of over two million a year in the 1970s.

And at the time led to a huge reduction in carbon emissions. The conversion exercise was, in the words of Sir Dennis Rooke, chairman of British gas at the time. Perhaps the greatest peacetime operation in the nation's history. So it could be possible, but is hydrogen really greener?

- You can make hydrogen in a few different ways. And at the moment it is actually made from fossil fuels in the UK majority of the time.

- Just to interrupt Jess, to make sure you heard that. At the moment hydrogen is actually made from or extracted from fossil fuels.

- So basically you take a bit of natural gas and you do something called steam methane reformation , which sounds really complicated, but it's not that complicated. It basically just splits up the gas to create hydrogen as a byproduct. And that's how it's made at the moment. So it's not very clean.

- That's what's known as grey hydrogen. And there is an option to capture the carbon produced in the process leaving what's known as blue hydrogen. Both though do come from fossil fuels.

- But there is an option in the future to make green hydrogen, which is basically when you take water and you take spare electricity from say a wind turbine, or a wind farm, and you use that electricity to split the water up from H2O to hydrogen and oxygen. And then that is a much cleaner way of making hydrogen, which can be sort of more aligned with the UK's climate change targets. But that unfortunate at the moment is still very much in the development phase.

- So, Yeah. If we could make enough green hydrogen then, brilliant. But it looks like any new hydrogen homes are going to be relying on grey or blue hydrogen for a while.

- I'd love to talk hydrogen.

- Oh. If we must.

- This is Karen from Which again, who has studied the committee on climate change's projections more than most in it. The government reveal how they expect the UK's future heating network will shape up. By 2050 they say they're aiming for 57% heat pumps, 19% low carbon district heating, 14% hybrid hydrogen stroke heat pumps, and 10% other. So what does she think?

- Yeah. Well, it's a tricky one because it's clearly being pushed by quite a lot of people and I'm not convinced that it has a massive part to play.

- I picked this up with Jess too.

- There's a big gas lobby in the UK and they are really putting lots of money into hydrogen to do trials and to see how much it can be used for heating.

- A gas lobby? Well knowing what we now know about where the hydrogen we might use comes from fossil fuels, I can't see why some people are suggesting that the push for more hydrogen homes may be driven not by a green agenda but by the industry manufacturing, and supporting it. And what is clear is that hydrogen might not be the green future of home heating that I certainly thought it could be.

There are, of course, lots of options for more quite sustainable ways to heat your home both now and in the future, and obviously don't have time to investigate them all this week sadly. But there is one final area I want to briefly look at. I mentioned it just now when reading out the committee on climate change is projections. I said that by 2050 they're aiming for 19% low carbon district heating. So what is this excitingly named district heating, I hear you ask?

- District heating sometimes known as heat networks, they are a way of generating heat at one central point and then distributing it to a whole bunch of houses flats, and also commercial buildings as well. They've actually been around for in fact, a very long time. If you back to the Romans.

- I hadn't heard of this but you may have. Because according to the association for decentralised energy, there are already 17,000 district heating networks in the UK supplying almost half a million consumers. Which if this is a greener option for home heating is, great news. However sadly the majority of these networks are currently based around heat produced by burning fossil fuels. The idea is 2018 report says 56% are fueled by natural gas, and another 32% by the more efficient gas CHP, combined heat and power, which is a little bit cleaner. More encouragingly though district heating networks are using increased proportions of other energy sources.

- They can be powered by all sorts of things. So for example, there's one in North London that runs from waste heat from the London underground. So they can use heat and energy from all sorts of different sources, and they then basically pipe hot water to all the buildings that need them. And all you have in your home is a heat exchanger that exchanges that heat from the pipe work through into your own heating system.

- I asked Norwegian professor of engineering Natasha Noer for her thoughts.

- Do you think that district heating is the most sustainable option that we have currently to heat our homes?

- It will be. Because you don't need to use just this municipal waste or bio, it will appear more and more that you can use these heat either from industry. In Norway we have a small town North Moderna, they are 100% based on waste heat from industry.

- So just like the example Karen gave with heat from the tube providing heating in North London, this is yet more evidence that waste heat can go to good use, rather than just escaping into the atmosphere and warming the planet. But again forgive me, there is a catch.

- You're using a central plant that combusts waste that is not clean, that is not green, that produces significant emissions.

- I think waste is treated in a different way, because of what else you should do with your garbage.

- So even in the place that I would love to live an apparent, happier, and greener Norway, a portion of their district heating networks are powered by fossil fuels. But is it too much for me to expect that these networks are entirely, or at least majority fully powered by renewable sources? If only a small amount of district heating comes from emission generating sources, is that still better than the current heating system we have here in the UK?

- Do you think it's going to help us decarbonize the system lower our carbon emissions?

- Yes absolutely. I think heat networks have got a massive part to play. Obviously they're not suitable everywhere, but they are particularly useful in urban areas and areas of dense building. Heat networks work very, very well when you've got a mix of commercial and domestic, because you're generating heat the whole time.

So when people aren't at home during the day and don't need the heating, you can be using it in buildings like schools, hospitals, leisure centres, that sort of thing. So you're using that during the daytime, you're using it in homes at night. So it makes the system even more efficient.

- According to the heat networks in the UK report I quoted earlier, heat networks can reduce UK building's carbon emissions by up to $1 million tonnes of CO2 each year. And that by 2030 that could be as high as 2.2 million tonnes of carbon emissions savings which sounds pretty good to me, and you'll be happy to hear there is no but this time.

We've heard the options. We've heard how green they are or could be, but what will they cost? I hear you yelling. It's all very well and good Greg telling us we need to change to a heat pump or whatever, but is it affordable for us to do so?

- I think we have to acknowledge that at the moment expecting people to decarbonize their heating, expecting people to replace a form of heating that is generally quite affordable for most people with something that's more expensive in terms of the actual boiler and potentially more expensive in terms of the electricity. It's just not going to happen without some form of incentive, or grant, or support, from the government.

- The government did offer help before in the form of the green homes grant. A 1 and 1/2 billion pound programme that offered households grants of up to 5,000 or 10,000 pounds to put in insulation or low carbon heating. But in March this year it was scrapped after just six months, leaving the UK without a plan for tackling one of the biggest sources of greenhouse gas emissions.

- Is it fair to say the green home grant was a bit of a failure? And if so does that give us any confidence for what comes next?

- The green homes grant it was actually a really, really popular scheme with consumers so they had I think it was over 160,000 applications in just six months. Which is huge.

- Although that was potentially part of its downfall too with such levels of interest people were waiting ages to get the vouchers. There were too few installers registered with the scheme for some people to get any work done, and there was also accusations that it harmed the renewables industry. As people were delaying getting work done while they waited for the vouchers, but the fact that the appetite was there from the public for them to do their bit for climate change is really encouraging. And it looks like the government is now looking at what incentives they can offer.

- So the government are looking at changing how some of the levies on gas and electricity bills are split up and kind of redistributing that so it's a bit more even. And that's because at the moment about 23%, about a quarter of an electricity bill is due to social and environmental levies, whereas only 2% of the gas bill is.

- 23% of electricity bill a Levy on social environmental 2% of the gas bill when our electricity mix currently is what 50% renewables, and gas is 100% gas is fossil fuel. So surely the levies from social and environmental should be higher on the gas than it is on the electricity?

- That's one of the arguments that people in the industry are making and they're saying that's not even switching at all but just distributing it so it's more even will hopefully encourage people to see electricity as more of an option for heating.

- It looks like cost may actually be the biggest obstacle of all then when it comes to swapping what we currently have for a greener alternative. However cost could also be the biggest motivator for the one thing we could all be doing to make our homes, not just more energy efficient but also save us money every year. It's the thing that every expert I spoke to this week said when I asked them what they would recommend that I do for my house, insulation.

- The one single thing that everyone can do is to make sure that their home is better insulated. And that means wall insulation, loft insulation, floor insulation, double glazed windows, draft proofing, all of those things that actually stop the heat that you've generated from escaping.

- V would I know as a homeowner which areas of my home I could improve the insulation?

- Well one of the ways that you can find that out is through your EPC.

- Your EPC or energy performance certificate to give it its full title. And you don't just get one for houses, you buy any property has one including rentals. Now I got an EPC when I bought my house about 18 months ago but like most things you receive in the mountain of paperwork when you purchase a place, I didn't give it much thought at the time.

- My name's Alan Bokeh. I'm director London EPC, and we do commercial and domestic energy certificates inside the 25.

- I sent Alan my EPC so he could tell me how efficient my house is. But firstly what does an EPC actually show us?

- So it's rated from I to j. Anything at the minute I to A is required for anything that's being rate. So Whether you're on a current lease, or a new lease, you have to get a minimum of an A rating. And that's with good reason, because actually J rating properties are going to be very inefficient, and that is why the government wants you to improve on that plus the bottom line.

The plan is that over the next few years, they're going to actually increase the minimum standard. So it's OK. Is it 2025? We're looking at D rating as a minimum and then at 2030 a C rating. So we have to have a lot of people coming to us and saying but we're looking to future proof. We want to make sure we're a C rating so that we don't have anything to do with over the next few years or as those minimum requirements go up.

- OK Cheers Alan. That's really helpful to know. So Gomen then how does mine look?

- So looking at it, it's actually pretty good. It's got here you've got 150 mil loft insulation. So you could potentially get a top up. So the standard these days is around 270 to 300 ml. So you could definitely look at getting a lot of top up on there, especially if you're looking at putting in heat pumps, insulation is absolutely crucial.

- Karen said the same when we were talking about heat pumps. She told me that it is possible.

- You can retain exactly the same radiator system with the same plumbing, as you've got in your current gas central heating, and you just switch out the gas boiler for a heat pump.

- However that depends on how well insulated your home is.

- The one thing that is not so great about them is that they tend to work at a lower temperature than your gas boiler. So a heat pump typically might heat the water in your radiators to 40 to 50 degrees, whereas your current gas boiler might heat it to more like 70 degrees. So what that does mean is that for a lot of homes you might find that you actually have to upsize your radiators because the heat that they supply isn't as hot. You need to insulate your home better.

So going back to the idea that a heat pump is like a fridge in reverse. If you imagine trying to run your fridge with the door open, that's a bit like trying to heat your house with a heat pump. If you're not very well insulated, you're pumping all that heat in but you're losing so much of it that it's inefficient. So actually you need a better insulated home if you're going to switch to a low carbon heating system.

- So what can I do to better insulate my home? Well according to the energy saving trust you could save around 155 pounds worth of energy with a cavity wall insulation, and 150 pounds by installing loft insulation. And at a cost of around 300 quid for loft insulation, you'll be in profit from the third year. What else then?

- Windows don't make quite as big an impact as insulation does just because the surface area. So windows maybe make up 10, 15% of the external fabric of the building whereas the walls and the roof are going to take up 80% to 90% of that. So those are the areas you want to look at first and then the windows. You really want a nice reasonably airtight building to work with.

- Would I also need to change out the natural gas boiler that I have?

- That's an interesting one because we've got a lot of people saying well you know everyone's moving away from gas and should be able to use electricity it is greener. But increases haven't really caught up with that, if you take out your gas boiler and you put in electric heating you will actually massively lower the rating because gas is basically a third of the price of electricity. I've actually had properties that spoiled and made that ripped out the gas boiler and I put an electric interest, at all while I've got these great new electric stuff installed, and that I can actually no longer let their property anymore.

- So I guess I naively thought that what you have mentioned that the more renewables I have could push me up into those higher bands of A and B. But now it sounds like if I actually switch to renewables, that could lower me because it's going to cost me more per unit energy?

- It could do. And that's going to affect obviously with a well insulated property with an associate. It will balance out a little bit, but yeah you probably will see a slight drop in the rating with an associate from.

- That seems bonkers to me. Does that suggest that we need to change the way that we do energy performance difficult moving forwards, if we do want to transition to more green fuels?

- Yes. Is the short answer that needs to be an overhaul or that. It's definitely something that needs to be looked at because people are basing decisions off of this now with the means regulations. An everything is quite limited it was never really designed to do that, it was invented back in 2007 the first series came out.

- Karen agrees that installing a low carbon heating system may increase the running costs, because of the higher cost of electricity versus gas. And because of the way the EPCs are calculated, that could indeed lower your energy efficiency rating. But it would improve the environmental impact rating, which used to be on the front page as big as the energy efficient rating, but has recently been moved to the last page.

So yes. The way EPCs are calculated at the moment means you are effectively being punished for making your home greener if that makes it more expensive to run. And the rating of its environmental impact has been relegated to the back. Well Allen suggested to improve my house is likely to be able to help improve yours too. The Office for National Statistics data from last year shows that only around 15% of existing homes were built after 1990. Meaning that the majority of homes were built before the introduction of standard for insulation and energy performance.

Their evidence suggests that over eight million layoffs require insulation or top up insulation, and that there are over 5 million uninsulated cavity walls. Plus I saw a report from the government that said that 2/3 of homes are rated D or worse on their EPC. It has definitely given me plenty of thinking to do, especially if I want to make the most of any newer greener way of heating my home. Which leaves me with one final question for Karen and one surprising answer.

- If I am going to be encouraged to replace my gas boiler, what am I going to replace it with?

- The point about replacing a boiler is most people do it as a distress purchase. The time when you replace your boiler is when it breaks down. And that's not a time to then be thinking, Oh how efficient is my home? What options do I have? What's the best type of home heating for me? So the best thing that you can do is to make your home efficient in advance of the time when your boiler next breaks down, so that you have got the option to potentially say, Oh actually my house is quite efficient I can instal a low carbon heat pump because my home is ready for it.

So I would say, yes. The next time most people replace their boiler, it will probably still be a gas boiler. But if you've prepared your home well enough. If you've got an efficient cosy house that retains the heat, you would be able to actually consider putting a heat pump in instead of a gas boiler.

- Wowsers, there you go. For all this talk of decarbonization there is still not a viable, affordable, fossil fuel free boiler alternative unless you've already improved your insulation. That is the reality right now. So I am definitely going to look at ways that I can improve the energy efficiency of my home. See if I can up the loft insulation, how air tight things are, maybe consider the windows after that. And then if the government will offer good incentives for me to buy a heat pump which hopefully will find out when they release their heat and building strategy very soon, I'll think about installing one of those. But I won't be considering hydrogen until I know it's green hydrogen. Not a fossil fuel wolf, an Eco-friendly clothing.

As ever I would love to hear your thoughts on this heat pump, hydrogen, district heating. What are your takeaways from this week's conversations and investigation? Let me know. I'm at Greg Foote on Twitter and Instagram, and Which is at Which UK.

- If you enjoyed this podcast, please do rate and review us wherever you get yours. It really helps people decide whether to click and listen. Please you spread the word as well. More episodes are on their way so follow us to catch them, and if you've got something you'd like us to investigate then please do let us know.

Here at Which we are making sustainability key to what we do from how we assess the products and services we review, to the way we run our whole organisation. That's why this first season of Which investigates is dedicated to helping you make the sustainable choices that you have told us are so important.

We've got new reviews, and advice every day on Which Doc at UK that will give you the power to make the best decisions for you and the planet. And if you want to make the most of your money with everyday personal finance tips, then why not have a listen to our sister show the Which Money Podcast.

Today's episode was presented by me Greg Foote. Written and produced by me and Rob Lily, edited by Eric Brea, and our executive producer is Angus Faqir. Special thanks go to Richard headland, Michael Briggs, Emily Seymour, Evet Fletcher, Karen Lawrence, Sara Ingrams, and Sam Morris. And I'll see you next time. [music playing]