WEBVTT NOTE Transcript 2024-05-19 from FLAC by https://elvery.net/prototypes/transcribe/ on my MacBook Air M1 on maximum quality setting. NOTE Body edited. 00:00.000 --> 00:05.000 So we all want to have warm homes and consume less energy. 00:05.000 --> 00:09.000 I think one of the things perhaps to understand when you're talking about houses, 00:09.000 --> 00:14.000 and I'm talking mostly about houses, not flats, is that they come, I mean, 00:14.000 --> 00:17.000 they're two basic sorts, particularly in Kingston. 00:17.000 --> 00:20.000 They're the houses that were built before the Second World War, 00:20.000 --> 00:23.000 which are one sort of house, so, and there's, 00:23.000 --> 00:27.000 they're houses built after the Second World War, and particularly more recent houses. 00:27.000 --> 00:32.000 So you might have heard the phrases "solid wall construction" and "cavity wall construction". 00:32.000 --> 00:38.000 So the houses that were built before the Second World War are mostly solid walls. 00:38.000 --> 00:42.000 We often call them brick-thick walls, sometimes rendered. 00:42.000 --> 00:46.000 They have raised timber ground floors, so they're lifted off the floor, 00:46.000 --> 00:51.000 and there are air bricks, which ventilate those timbers under the floor. 00:51.000 --> 00:54.000 They used to have single-glazed windows when they were built, 00:54.000 --> 00:57.000 and they have a loft space with a pitch roof. 00:57.000 --> 00:59.000 The other sort of house, which I'm talking about, 00:59.000 --> 01:04.000 which are more recent houses, might have a cavity wall more commonly, 01:04.000 --> 01:08.000 might have solid floors, although they could still have suspended floors, 01:08.000 --> 01:10.000 and might have been built with double glazing, 01:10.000 --> 01:13.000 and they might have some sort of loft insulation. 01:13.000 --> 01:17.000 So there's already a performance gap between those two sorts of houses, 01:17.000 --> 01:22.000 and houses that are being built today are just such a distance away 01:22.000 --> 01:27.000 from those pre-Second World War houses in terms of energy consumption; 01:27.000 --> 01:29.000 it's unbelievable. 01:29.000 --> 01:33.000 So one of the issues, really, that faces us in somewhere like this, 01:33.000 --> 01:41.000 where probably 75% of our stock in Kingston might be before the Second World War, 01:41.000 --> 01:45.000 I'm guessing a bit, but it's quite a lot, anyway, of all we have. 01:45.000 --> 01:49.000 So how are we going to make those houses perform better? 01:49.000 --> 01:52.000 Because it does help if the house performs better, 01:52.000 --> 01:57.000 if it doesn't lose as much energy when energy is becoming more expensive, 01:57.000 --> 02:00.000 and we want to produce it sustainably. 02:00.000 --> 02:06.000 So one of the things everybody looks at, draughts and air movement, 02:06.000 --> 02:11.000 because those are big factors in heat loss. 02:11.000 --> 02:14.000 I think it's, Damon would probably correct me, but I mean, 02:14.000 --> 02:17.000 it's something like 25% of our heat losses. 02:17.000 --> 02:20.000 30% is through ventilation ... 02:21.000 --> 02:22.000 ... unplanned ventilation. 02:22.000 --> 02:25.000 So even if you've insulated the walls, 02:25.000 --> 02:28.000 if you've got lots of gaps everywhere, 02:28.000 --> 02:30.000 you're still going to be using a lot of heat. 02:30.000 --> 02:33.000 Of course, as you start to shut up these gaps, 02:33.000 --> 02:40.000 you are keeping moisture within your house, 02:40.000 --> 02:44.000 and that's the root of a lot of the problems we're beginning to see. 02:44.000 --> 02:48.000 You know, we've heard of, I think it's called Abassa's Law, 02:48.000 --> 02:51.000 a little kid who died of a mould in his home, 02:51.000 --> 02:55.000 because when you start to put in double-glazed windows, 02:55.000 --> 02:57.000 you're starting to reduce that airflow. 02:57.000 --> 03:03.000 So the whole issue of draughts / ventilations is very interlinked here. 03:03.000 --> 03:06.000 So in older houses, this diagram just shows, 03:06.000 --> 03:10.000 in older houses we used to have the air, wind brought in air. 03:10.000 --> 03:11.000 There were gaps in the house. 03:11.000 --> 03:13.000 You had chimneys pulling the air out through the house. 03:13.000 --> 03:16.000 That provided a natural circulation of air 03:16.000 --> 03:19.000 and kept moisture levels reasonably low 03:19.000 --> 03:21.000 and kept us cool in summer. 03:21.000 --> 03:23.000 So as we start to... 03:24.000 --> 03:26.000 As we start to put double-glazed windows in, 03:26.000 --> 03:28.000 this is the kind of thing you see, 03:28.000 --> 03:31.000 where that's a double-glazed window. 03:31.000 --> 03:33.000 If you then shut up your fireplace, 03:33.000 --> 03:35.000 which is something you want to do, 03:35.000 --> 03:37.000 I mean, you want to close up your fireplace, 03:37.000 --> 03:42.000 but you've got to pay attention to bringing some fresh air in, 03:42.000 --> 03:45.000 and not letting too much moisture accumulate 03:45.000 --> 03:48.000 to avoid this kind of dampness. 03:48.000 --> 03:50.000 And if you look at pictures of places 03:50.000 --> 03:52.000 which are identified as being damp, 03:52.000 --> 03:54.000 this is often what you see. 03:54.000 --> 03:57.000 And it's not dampness in the way we used to think of it 03:57.000 --> 04:00.000 when it was water coming up through the walls 04:00.000 --> 04:02.000 or rain being driven through the walls. 04:02.000 --> 04:04.000 It's dampness internally. 04:04.000 --> 04:07.000 Because we take showers, we cook, 04:07.000 --> 04:10.000 people sometimes dry washing indoors, 04:10.000 --> 04:13.000 particularly in flats, it's quite a common problem. 04:13.000 --> 04:16.000 And we breathe, and that all creates this sort of difficulty. 04:16.000 --> 04:18.000 So you have to be careful what you're doing. 04:18.000 --> 04:20.000 So this is about ... 04:20.000 --> 04:24.000 This is about where you might want to seal your house up 04:24.000 --> 04:28.000 to try and lose these, to try to stop the loss of heat. 04:28.000 --> 04:33.000 And a very common problem that people are not really very clear about 04:33.000 --> 04:35.000 is when you... 04:35.000 --> 04:38.000 There was a trend for having timber floors, 04:38.000 --> 04:41.000 exposed timber floors in the '70s, I guess. 04:41.000 --> 04:43.000 Lots of people sanded their floors. 04:43.000 --> 04:46.000 I mean, I just mentioned earlier on that the... 04:46.000 --> 04:49.000 There are air bricks on the outside of the house 04:49.000 --> 04:51.000 and there's a continuous passage of air under it. 04:51.000 --> 04:54.000 Well, that is leading to quite a lot of heat loss, 04:54.000 --> 04:56.000 and people sometimes don't appreciate that. 04:56.000 --> 04:59.000 So when you put fitted carpets in, 04:59.000 --> 05:01.000 of course you're sealing off that area 05:01.000 --> 05:05.000 and you are reducing the heat loss through that. 05:05.000 --> 05:10.000 But all these places lose heat and energy. 05:10.000 --> 05:13.000 So... But you can start to do some things. 05:13.000 --> 05:17.000 I would really recommend anybody who's living in a house like this 05:17.000 --> 05:19.000 that's got timber ground floors. 05:19.000 --> 05:21.000 I'm just talking about ground floors here. 05:21.000 --> 05:25.000 First floors are irrelevant because they're already inside the shell. 05:25.000 --> 05:29.000 But ground floors, if you're having your carpet refitted, 05:29.000 --> 05:32.000 it's really worth taking the opportunity to... 05:32.000 --> 05:35.000 I mean, this is disruptive, but it's worth it. 05:35.000 --> 05:37.000 Take all your furniture out of the room. 05:37.000 --> 05:40.000 You've got to take it all out to have it refitted with a carpet anyway. 05:40.000 --> 05:45.000 Lift the floorboards up and put insulation between the floorboards. 05:45.000 --> 05:48.000 And that's... The way these things are done is you can see 05:48.000 --> 05:50.000 that the timber joists are still exposed, 05:50.000 --> 05:53.000 so it's still got air circulation under it, 05:53.000 --> 05:58.000 which stops it rotting because often the underfloor spaces 05:58.000 --> 05:59.000 are a little bit damp. 05:59.000 --> 06:02.000 Put it and then put insulation in between, 06:02.000 --> 06:04.000 and that will help to reduce your heat loss 06:04.000 --> 06:07.000 before you put your carpet back on. 06:07.000 --> 06:11.000 I mean, modern houses all have pre-insulated ground floors. 06:11.000 --> 06:14.000 Yeah. I suppose you might not recognize it, 06:14.000 --> 06:17.000 but when you take the floorboards up on your floor, 06:17.000 --> 06:20.000 that's what you see. You see this pattern of floor joists. 06:20.000 --> 06:22.000 The thing is that the cavity walls, 06:22.000 --> 06:25.000 your house either has a cavity wall or it doesn't. 06:25.000 --> 06:27.000 And there are probably relatively few houses in Kingston 06:27.000 --> 06:29.000 that have cavity walls. 06:29.000 --> 06:33.000 So that is not an option for a lot of people in Kingston to do this. 06:33.000 --> 06:37.000 So there are a couple of options if you haven't got a cavity wall. 06:37.000 --> 06:42.000 One is internal wall insulation and one is external wall insulation. 06:42.000 --> 06:44.000 So just starting with internal wall insulation, 06:44.000 --> 06:48.000 that's where you're adding some kind of insulating material 06:48.000 --> 06:50.000 on the inside of the walls. 06:50.000 --> 06:53.000 And there are some... I mean, there are some problems with this. 06:53.000 --> 06:55.000 I mean, it's quite expensive to do. 06:55.000 --> 06:57.000 It's quite disruptive. 06:57.000 --> 07:00.000 And you have to be careful about where... 07:00.000 --> 07:05.000 You can create a situation where you get condensation inside that wall. 07:05.000 --> 07:07.000 So condensation occurs. 07:07.000 --> 07:10.000 So you've got the warm side of the room where he is. 07:10.000 --> 07:13.000 Then the temperature is dropping through the wall 07:13.000 --> 07:15.000 to the temperature it is outside. 07:15.000 --> 07:19.000 And if you allow moist air to pass through that construction, 07:19.000 --> 07:23.000 it will condense somewhere in the middle of that. 07:23.000 --> 07:25.000 So you've got to... If you're not careful. 07:25.000 --> 07:28.000 If you're not careful, yes. So it's got to be done quite carefully. 07:28.000 --> 07:30.000 And the other problem with this, obviously, 07:30.000 --> 07:33.000 is you've got mouldings in a Victorian house. 07:33.000 --> 07:35.000 You have to replace those. 07:35.000 --> 07:38.000 But you can do it and it can be made to work. 07:38.000 --> 07:42.000 There are some other problems with cold... with joists and things. 07:42.000 --> 07:44.000 Anyway, so it's tricky. 07:44.000 --> 07:48.000 And this is why, in a way, people are not doing this so much. 07:48.000 --> 07:52.000 It's better to do what you can do reasonably easily in a way 07:52.000 --> 07:54.000 and then have an air source heat pump, 07:54.000 --> 07:56.000 which, if we're all worried about the climate, 07:56.000 --> 07:58.000 is what's really going to make the difference. 07:58.000 --> 08:01.000 So that's the external option. 08:01.000 --> 08:04.000 Now, I mean, there are quite a lot of rendered houses in Kingston, 08:04.000 --> 08:06.000 and that is an option for them. 08:06.000 --> 08:09.000 And it is quite a good system because it does... 08:09.000 --> 08:11.000 It makes the whole... 08:11.000 --> 08:13.000 It is putting a tea cozy round the house, really, 08:13.000 --> 08:14.000 and it will reduce it. 08:14.000 --> 08:17.000 But that is quite an expensive thing to do. 08:17.000 --> 08:19.000 But it's not hundreds of thousands to do that. 08:19.000 --> 08:22.000 I mean, I think that's more like 25... 08:22.000 --> 08:25.000 This is the thing that most people do, 08:25.000 --> 08:28.000 and it is the thing that you should all do. 08:28.000 --> 08:31.000 And if somebody says to you, they've insulated their loft, 08:31.000 --> 08:34.000 if you look at the depth that they're talking about here, 08:34.000 --> 08:36.000 because the depth has risen and risen and risen 08:36.000 --> 08:39.000 since I've been working on buildings. 08:39.000 --> 08:41.000 So it used to be 100 millimetres 08:41.000 --> 08:43.000 and we're now at nearly 300 millimetres. 08:43.000 --> 08:47.000 So it is well worth everybody making sure that your loft is properly insulated, 08:47.000 --> 08:49.000 because that's an easy thing to do. 08:49.000 --> 08:52.000 I mean, I say it's easy, because it isn't that easy, 08:52.000 --> 08:55.000 because we all fill our lofts full of a load of rubbish. 08:55.000 --> 08:56.000 And then you've got to... 08:56.000 --> 08:57.000 If you want to put that rubbish back, 08:57.000 --> 09:00.000 you've actually got to build a platform on top of it 09:00.000 --> 09:02.000 to let the insulation run under the top. 09:02.000 --> 09:05.000 But it is still, relatively speaking, the easiest thing to do. 09:05.000 --> 09:07.000 So well worth considering. 09:07.000 --> 09:13.000 Now, the other thing to understand is that the physics of houses 09:13.000 --> 09:16.000 is relatively simple, but you ventilate. 09:16.000 --> 09:20.000 That space under your roof, you really want to ventilate, 09:20.000 --> 09:23.000 because moist air will rise up through your ceilings. 09:23.000 --> 09:28.000 And I talked about moisture condensing. 09:28.000 --> 09:31.000 What you do with the roof, where it rises through the loft, 09:31.000 --> 09:36.000 you have to keep it ventilated so that that moisture will be dispelled. 09:36.000 --> 09:39.000 If you close up all your eaves and seal everything off, 09:39.000 --> 09:43.000 and that can be a problem with some sorts of insulation system, 09:43.000 --> 09:46.000 the thing won't perform properly. 09:46.000 --> 09:50.000 But I mean, most traditional houses have eaves ventilation. 09:50.000 --> 09:52.000 If you go up in your roof space, 09:52.000 --> 09:55.000 you can often feel a bit of air movement, and that's a good thing. 09:55.000 --> 09:59.000 That's what you want, provided your insulation is at ceiling level. 09:59.000 --> 10:00.000 That's just repeating that. 10:00.000 --> 10:01.000 And that's talking... 10:01.000 --> 10:05.000 This is a trickier problem to insulate 10:05.000 --> 10:07.000 where you're following a line in the ceiling, 10:07.000 --> 10:10.000 and you haven't got a big depth. 10:10.000 --> 10:12.000 And there are various solutions to that. 10:12.000 --> 10:15.000 You can actually put the insulation on the outside of the roof, 10:15.000 --> 10:19.000 or you have to keep a ventilated void on the other side of that, 10:19.000 --> 10:21.000 again, to dispel the moisture. 10:21.000 --> 10:26.000 Or you can go for trying to completely seal it from the inside. 10:26.000 --> 10:29.000 But it has to be carefully thought through. 10:29.000 --> 10:32.000 And that's a bit more of a discussion. 10:32.000 --> 10:35.000 This is how you prevent the condensation of the roof space 10:35.000 --> 10:37.000 by bringing the air in at the eaves. 10:37.000 --> 10:39.000 Now, the other thing to talk about is... 10:39.000 --> 10:43.000 So when you've done all this, if you do a lot of sealing up, 10:43.000 --> 10:44.000 then the question is, 10:44.000 --> 10:47.000 how do you make sure that you don't get this condensation 10:47.000 --> 10:48.000 I've been talking about? 10:48.000 --> 10:52.000 So the building regulations has some solutions to that. 10:52.000 --> 10:53.000 So when you... 10:53.000 --> 10:55.000 They ask you to put... 10:55.000 --> 10:57.000 There are various ways of doing it. 10:57.000 --> 11:01.000 One way of doing it is to put what we call "trickle vents" in your windows. 11:01.000 --> 11:02.000 So if you look at... 11:02.000 --> 11:04.000 when people have replaced their windows, 11:04.000 --> 11:08.000 you'll often see these little grilles at the top with a sort of flick, 11:08.000 --> 11:10.000 so you can have them open or shut. 11:10.000 --> 11:11.000 And that's what that's about. 11:11.000 --> 11:16.000 That's supposed to be providing a little bit of fresh air into the home. 11:16.000 --> 11:19.000 And then they're also building regulations 11:19.000 --> 11:23.000 for having fans in your bathroom and your kitchen. 11:23.000 --> 11:25.000 Again, that's another place. 11:25.000 --> 11:27.000 That's where you're generating the moisture, 11:27.000 --> 11:30.000 because you want to get that out of the room. 11:30.000 --> 11:32.000 A more sophisticated approach 11:32.000 --> 11:36.000 and what happens in new buildings now is something called... 11:36.000 --> 11:39.000 is a system where you actually extract the air 11:39.000 --> 11:42.000 and you pass it through a heat exchanger somewhere in the building, 11:42.000 --> 11:44.000 maybe in the loft or in a hallway. 11:44.000 --> 11:46.000 And that preheats air coming in, 11:46.000 --> 11:49.000 so that's an even more efficient way to do it. 11:49.000 --> 11:52.000 But what's particularly dangerous is if you don't do any of those, 11:52.000 --> 11:54.000 if you put in double glazing, 11:54.000 --> 11:55.000 you seal up your chimneys 11:55.000 --> 11:58.000 and you seal up all the ... draught proof the doors, 11:58.000 --> 12:01.000 and then you don't do anything else about ventilation, 12:01.000 --> 12:05.000 you are in danger of getting condensation in the building.