Planet Earth Online - The Energy Costs of Old Architecture
Diana - If you live in an old or historical building, and let's face it here in Cambridge the chances of that are very high, then you're also probably aware that there can be downsides too. Sometimes all the features that make a building beautiful such a skylights, architectural touches and masonry, contribute to it being a cold and drafty dwelling. So how do you make buildings that are hundreds of years old energy efficient without tearing them down and starting all over again? Planet Earth podcast presenter, Richard Hollingham, went to London to find out...
Richard - I'm at the back of Paddington Station in West London, next to a fairly busy road, and with me is Bob Lowe from the UK Energy Research Centre. One of his areas of research is how to improve the energy efficiency of cities. Now Bob, you're a building physicist, so let's look at this building here. It's, what, a five story building. We reckon between us (neither of us are architects) about 200 years old. It's got a rather nice cream facade, large sach windows, surrounded by this ornate masonry. And there's a balcony running the length of the building. This is a nice building, you would not want to tear it down, but I guess it's not energy efficient.
Bob - It probably isn't energy efficient. Things will have been done to it over the years, it's almost certainly got some double glazing - in fact, I can see the double glazing in there. It will have modern heating and ventilating systems inside. But basically the envelope is solid wall with no insulation, very high heat loss. So if you want to do something about the energy consumption of London as a whole, you actually have to deal with hundreds of thousands of buildings like this in order to correct that problem. And nationwide, there is something like 7 million solid wall buildings.
Richard - Just on the junction we're standing at, these buildings stretch all the way down the street into the distance, we are surrounded by them, so here's the question: how do you make this more energy efficient?
Bob - We did have a look at the back on our way round and one of the things about buildings of this age is that very often the back is much much more plain than the front. It actually turns out that you have more wall area at the back. Because the wall goes in and out with things that up in Yorkshire we call off-shots, I don't know what you call them down here - kitchen extensions and so on - built in when the buildings were first built. So you've probably got 50% more wall area and, in principle, you can insulate it.
Richard - The thing is, you wouldn't design a modern city, if you were trying to reduce its carbon footprint, like this. The junction here for example, with blocks of four roads going off in each direction, busy roads, and solid walls.
Bob - And yet there were some things that the Victorians got very very right indeed. These days, it's almost impossible to replicate this kind of urban environment under modern planning rules - with rules for roads, turning radiuses for traffic and so on, so this is very very difficult to replicate.
Richard - So what's good about this?
Bob - What we have here is very high density, it's then relatively straightforward to connect this to effective public transport systems, buses, the underground system, something that occurs in very few other cities in the UK. I can think of maybe 2 or 3 cities that have significant underground railway systems. So what we have here in transport term is extremely efficient. And you've got to remember that building energy consumption is only about 30% of total energy consumption in the UK, and transport is nearly as important and growing much faster.
Richard - So if you're looking to retrofit a city - to make it greener - you've got to look at all these things. You've got to look at the clad in the buildings, the transport system, where the energy comes from, the whole lot.
Bob - That's right. At the moment these buildings are almost certainly heated by gas supplied with electricity from power stations in the rest of the country. Well, in terms of the gas heating, it would be possible to heat the area here with hot water supplied from nearby power stations through pipes - something that's done in many towns and cities in places like Denmark and Sweden, parts of Germany and so on. That would require significant interventions across the city, it would require a level of planning which the UK has not been that good at over the last 20 or 30 years since I became involved in this kind of work. These are real problems that don't go away.