Transcription
And the since I've moved into this old cottage ten years ago, I've been grappling with condensation and mould in the cold winter months. So, in today's video, I'm going to tell you what causes it, what steps you can put in place, and what steps I've taken and how effective they've been. Through some pretty exhaustive research I've been carrying out over the last two years, the over this video is to demystify this difficult subject so that I can help you tackle the problems you've got in your own home.
[Applause]
Now, damp and mould, and to a lesser extent condensation problems, stemming from the humidity levels in your house, or relative humidity levels, we'll come on to that later. But, hi, so that's quickly run through the five main sources or generators of moisture humidity in your home. Number one, we've got cooking and kettle boiling. Number two, we've got bathing. Number three, washing. Number four, breathing, and that accounts for half a litre a day per person. And if you're exercising in your house, you can probably triple that. And number five, moisture in the house through basements, crawl spaces, and walls.
Now, these moisture generators exist all year-round, but in the winter, the problem comes to a head because the winter is heating season. We close our windows and we reduce ventilation and circulation of the air in our home to keep out the cold. The same time, rain and melting snow can increase the moisture entering our home through the crawl spaces, basements, and walls, as I mentioned just now. As less moisture leaves the house, humidity levels start to rise. At the same time, you get condensation because parts of the house that are in direct contact with the cold air outside are cooler than the air inside. An example of that is single glazed windows and insulated walls. The temperature difference combined with warm, moist air can cause condensation on those surfaces.
So, what happens if you fail to manage that increased moisture during the winter months? Well, for a start, all that wetness will attract mould growth and moisture stains. And in the worst case, as you can see here, the fabric of your house, particularly plasterboard, will start to rot. Unsurprisingly, it can also have an adverse impact on our health, as we need normal humidity to feel comfortable. Too much moisture can cause allergies and the static conditions. Dust mites, for example, thrive at 23 to 27 degrees or a relative humidity of 70 to 80%, but actually stop growing and die out at humidities of less than 60%. And modern US humid conditions at a relative humidity of 80%, mould will grow 50% of the time. And mould spores can contribute to in children and colleges. And finally, excessive moisture has an impact on electronics as well. It can corrode contacts and cause short circuits, as I found out to my cost when I left my dad's Olympus OM-1 camera in my damp basement.
So, that's all pretty straightforward and, dare I say, a bit obvious. But this is where it gets more interesting because if you're going to understand your own humidity problems, the extent of those problems, or what you've got to do to solve them, you've got to be able to measure the humidity in your own home. And point two, you've got to understand a little bit more about the science behind it. So, a year ago, when I started researching for this video, I bought this hygrometer. This gives me the ability to measure indoor temperature but also humidity in both Celsius and Fahrenheit. More recently, to capture as much data as possible, I bought this additional hygrometer. This is a wireless indoor and outdoor humidity and temperature monitor. It comes with an additional sensor which has given me the ability not only to set up another internal temperature point but also to monitor the outdoor temperature and relative humidity. These things are cheap and an absolutely essential purchase if you're going to tackle the problems you've got in your house. I'm showing you eBay prices here. I bought mine from Amazon, but for some reason, they're currently unavailable on the Amazon website.
And why have you got to measure relative humidity? Well, because anything below 30% is too dry, as indeed you find sometimes outside during the winter because you can get chapped lips, dry skin, and itchy eyes. You want your house to have a relative humidity of between 40 and 60%. Anything over 60% can lead to the mould, damp, and condensation problems we've just discussed. And a quick glance of the hygrometer shows you what the relative humidity levels are in your house at any given moment.
But what I keep talking about relative humidity rather than just humidity? Well, put simply, you can't just talk about humidity in isolation because the temperature of the air affects the amount of moisture the air can hold. Vapour pressure also comes into it, but we won't worry too much about that in today's video. So, relative humidity is the amount of moisture in the air relative to the amount of moisture that air can hold, influenced by its temperature. In short, the warmer the air, the higher its capacity to hold moisture. And that's really important because when you go out and buy your hygrometer and turn the heating on, you'll actually find the relative humidity level in your house drops. Now, that doesn't mean the moisture content in your air has dropped, far from it. What that means is that capacity of the air to hold moisture has gone up. So, if anything, you're just masking the problem that already exists.
And here are a few examples to illustrate the point. A drop in temperature of 10 degrees Celsius halves the amount of moisture that the air can hold. Now, a 100% relative humidity is also called the dew point. And you'll see here from this graph I pulled off Wikipedia, the amount of water in our 100% relative humidity across the range of temperatures. Linked to this and everything else I've referred to in this video will be in the description below the video.
So, why is he boring us about relative humidity, I hear you ask? Well, I'll tell you why. It's really important to understand relative humidity if you can get to the bottom of why you're getting condensation on your windows. And here's why. Condensation forms when airborne water vapour comes in contact with a surface which is colder than the dew point. And by that surface, we're typically talking here about single glazed windows. And what happens is that surface cools the air immediately next to the window itself. And as we now know, when you cool air, it can't hold as much moisture. So, the net result is the relative humidity in that little area of air next to the window goes up. When that relative humidity level gets to 100%, it reaches saturation point or its dew point. And the air next to the window can't hold any more moisture, so it deposits it on the cold window. So, what you've effectively got on, what I've got with my bay windows, is a massive dehumidifier. Not very helpful for us, but you can understand why it's a dehumidifier because it's basically extracting moisture out of the air.
And talk of dehumidifiers brings us neatly on to the final part of this video. What we can do to resolve our humidity problems. Now, the gold standard for damp, mould, condensation management is new builds that incorporate complete home ventilation systems that basically keep the air around the home constantly circulated. These systems are enjoyed because they remove the existing air through multiple extraction points and pump in fresh, filtered air. Crucially, via the heat exchanger, they ensure that 95% of the heat that was in the air already is retained in spite of the fact that they're constantly recycling it. And the other thing they do is actively monitor the relative humidity levels so that they can boost the system should those levels rise too high. An example being this newer home ventilation system that was in a new build that I was measuring up for soft furnishings in last week. That even has a heat extraction point in the comms cupboard.
But sadly, you and I don't have access to these sophisticated home ventilation systems. So, for the remainder of this video, I'm going to run through the things that we can do to creatively tackle the humidity problems that you and I've got in our homes. I'm going to be touching quickly on three main points: lifestyle, dehumidifiers, and insulation.
So, what do I mean by lifestyle? Well, damp, mould, condensation problems are often attributable to lifestyle. Remember when we were talking, let's start about the main sources of moisture in our home: cooking, bathing, washing, breathing. Now, obviously, we can't do much about hot breathing, but we can have a massive impact on the moisture being released into the air through these other sources. When it comes to cooking, if you've got an extract fan, you should always use it. And in fact, when we forget to use ours, the windows very quickly get covered in condensation. To have a massive impact on removing moisture from the room. When it comes to boiling the kettle, I always phone catch the kettle just after the water starts at boiling point. I'm OCD, but just look how long this kettle boils for if you don't. And if your kettle is anything like mine, it's releasing a ridiculous amount of moisture into the air, as opposed to using up too much electricity. And when I've used that kettle, I typically put a bit of cold water in so that it doesn't sit there steaming for the next ten minutes.
If you haven't got one already, you should really try and install an extract fan in your bathrooms, or something like this. This one switches on when you turn on the lights and only switches off when the inbuilt humidistat decides that the moisture levels have dropped to the right level. This is particularly good for landlords anxious to keep moisture levels low in rental properties where you don't want your tenants to override and switch off the extractor fan. The next to bathroom washing management points are really important. That's sadly something that landlords cannot have any control over their tenants on. In our house, we have a strict rule of opening the window when we have a shower, which is mostly complied with. What Docks is getting a bit slack on it. And you can see from this clip just how much moisture escapes through the window during showering. And finally, our fridge shower. We've got into the habit of squeezing down the shower screen walls and even the shower tray. Fundamentally, this is great if you live in a hard water area to prevent limescale on your glass, but also it removes an incredible amount of moisture. As an experiment this morning, I used our cottage window back to do exactly this, and this is how much moisture was removed. A staggering 200 millilitres of water that would otherwise have simply evaporated back into the air during the day. With these simple steps, we generally get no condensation on the mirror glass. The entire room is generally dry within 10-15 minutes, including the ceilings, which is venting all that moisture from escaping elsewhere into the house. So, that's bathrooms taken care of. Elsewhere in the house, wherever you can, if you've got trickle vents, try and keep them open during the winter. It's not going to permanently flush and recycle the air like one of those home ventilation systems is going to, but it's definitely going to help to bring fresh, less humid air into the house, thereby diluting what's here already. And if we take another look at that dew point graph we saw earlier, you can see just how much drier the air outside is than the air is typically inside your home during winter months.
One final point before we move on. Let's have a quick chat about drying racks. Dry racks are obviously a bit of a disaster area when it comes to moisture in the house because all of that damp that in the clothes is basically being lifted out and deposited in the air, which is going to have a very negative effect on the relative humidity levels inside your house. Now, wherever you can, you should obviously use a tumble dryer. But I know this is difficult if you're in a rental property and you haven't got one, or you can't afford the increased electricity bills that tumble drying will incur. Admittedly, has. But just hold that thought. And later on, I'm going to be talking to you about dehumidifiers, which are a really great product in way of giving you the ability to use drying racks whilst also extracting the moisture from the air that's caused. So, that's how lifestyle can impact on the humidity levels in your house. Let's now talk about dehumidifiers and positive input ventilation systems.
So, in our existing homes, it's simply not practical, let alone cost-effective, for us to install all the ducting that will be required for one of these heat recovery systems we saw earlier. But often, the next best thing is perceived to be a positive input ventilation system. As you can see here, with these two new air systems for flats and houses with lofts. The idea of this system is you install it in the loft in a central location, and it pumps fresh air into the house via the loft space in order to try and circulate the air around your house. So, all these systems are great because they do away with all that ducting that you need with a proper heat recovery system that you and I just can't practically install in our old houses. I do see a couple of problems with these units. Number one, from the research I've done, from the forums I've visited, people say that in the absence of a proper heat recovery unit, even with the 400-watt heater, which after all only tempers the air coming into the house, it does create very chilly spaces where the unit's located, and your electricity bills could rise significantly reheating that space. Point two, in my house, I can't install one of these units because this corridor would be the obvious place to install it, but unfortunately, this is not loft above here. It's the valley between two roofs. And you're not meant to install them in the bathroom where I do have a loft because if somebody just had a shower, all the unit's going to be doing is flushing that moist, damp air all around the house. But do let me know in the comment section below if you've had one of these units installed, whether you found that unmanageably chilly in the area where the unit's been installed, but also whether you found it sorted out your condensation problems, because I'm a little bit skeptical as to whether, in the absence of all those extraction points, fire or that ducting you saw in the heat recovery systems, whether a small system like this PIV is going to be able to efficiently circulate the air well enough to prevent condensation occurring, particularly given in a lot of our homes we're going to have doors shut, which is going to provide a block for all of that air trying to circulate around.
But if you can't increase your ventilation, it's not practical to leave your windows open in the winter, and you've got a heap of washing lying around drying all the time, and are suffering from damp, then this section is going to be of interest to you. Let's talk now about dehumidifiers. And we'll quickly run through first the options that are available. First up, we've got small thermoelectric dehumidifiers, followed by moisture absorbers like this Aero 360. Small thermoelectric dehumidifiers are of very limited benefit, can generally only cope with extremely small spaces like cupboards. Equally, moisture absorbers like these can only move very small amounts of water. You may have seen a video done a couple of years ago on this system. I bought five of these stupid things, and they were absolutely hopeless in solving my condensation problems. Would stir when the tablets fully dissolve, you've got to buy a new set, and you're left with this horrible blue slurry in the unit. So, these units are about as practical as a chocolate teapot.
But all is not lost. There was some positivity out of me buying these because on the back of the video I did, I got contacted by Ebac a year ago to ask me if I was interested in trying out one of their dehumidifiers. So, if you're now thinking about buying a dehumidifier, you've basically got two options. You can either buy a desiccant dehumidifier, or you can buy a compressor. You're going to have to decide whether a compressor or desiccant is most appropriate for your situation, but here are the differences to help you make your decision.
So, desiccant dehumidifiers work by drawing air over desiccant attached to a slowly rotating wheel. The desiccant removes moisture from the air, thereby drying it, and then a separate heater heats up that desiccant in order to extract the moisture from it. Desiccant dehumidifiers are not temperature-dependent, so you can use them in much cooler conditions than you can compressors. They tend to be quieter, but I stress that is on the low fan setting. I've seen a lot of comments on Amazon purchases where people say on the high setting, they are quite noisy. And they're generally lighter. And finally, because a desiccant has to be heated to extract the moisture, they're perceived to be more expensive to run than compressors.
Compressor or refrigerant dehumidifiers basically work like little fridges. Air is drawn over cold coils which are effectively below the dew point, just like that window analogy I showed you earlier on. And because of that analogy, they have to operate in warmer conditions than desiccants, typically in temperatures above 3 degrees. They're generally lower energy consumption, and as I'll come on to in a minute, particularly with the Ebac smart mode, the operation is much more intelligent, more sophisticated than the basic humidistat operation of a desiccant dehumidifier. And price-wise, there's very little between them if you compare this Meaco desiccant with this Ebac compressor on Amazon.
Now, which dehumidifier you go for is a tricky decision, but one you need to get right because if you don't, you'll end up either not solving the problem, or you'll end up having much higher electricity bills. I've got to confess, I only have experience with the compressor dehumidifier, which I'll come on to in a minute. And I used to think desiccants were more for sort of disaster flood relief, that sort of thing, where you've got high volumes of water to remove when cost isn't really an issue. But the Meaco that I showed you a minute ago has had pretty good reviews. And clearly, if you're operating this machine in very low temperatures, unheated buildings like garages, for example, then the desiccant dehumidifier is the one for you because it's not temperature-dependent. The only issue I've got, though, is that desiccant dehumidifiers, like Meaco, tend to have a very basic humidistat system. In short, you set the system to a fixed relative humidity value, whether it's 40, 50%, and then the dehumidifier has to try and reduce the relative humidity to that level. Clearly, like your bathroom extract humidistat, if you set it too high, it never switches on. If you set it too low, and it never switches off. What concerns me is that dehumidifiers need to respond to both indoor and outdoor conditions in order to reach optimal operation. Optimum relative humidity varies from day to day, and even during the day, and every house will have its own optimum humidity level. If you've got, for example, a desiccant dehumidifier set to a low RH level, and the danger is it'll start pulling moisture out of furniture, walls, windows, floors, and obviously that is both unnecessary and costly on your bills.
So, when you're doing your research, be wary of review sites like Which, which rate dehumidifiers according to how much water they extract, rather than actually getting a handle on controlling the humidity in your home. The Ebac that I've been trialing for the last year or so has a smart control system. And the idea is, when you first set the unit up, it runs in smart control mode for 24 to 48 hours, basically monitoring humidity and taking data for that first period. It then switches on and off automatically at the most economical times to keep the humidity at the correct level. If you want to increase the airflow, you can run it in the max mode, and in this mode, you can set different time periods between two, four, and eight hours before it reverts back to the smart mode again. There's also a laundry mode, which again can be set for a certain amount of time. Remember we were talking about laundry earlier on? If you've got a room that's difficult to ventilate where you've got all your laundry hanging, stick this machine on laundry mode, and it will suck all the water out of that laundry, preventing it from circulating elsewhere around the house. You can change the fan speed, and you can also simply run the unit in air purifying mode. And whilst the water container holds over two litres of water, it can be bypassed with the drainage kit, as indeed can the Meaco. And this is a fantastic solution if you're a landlord worried about tenants being too lazy to empty the container, or if you've got a property you don't visit very often.
So, the suggestion is to place this unit in the coldest, dampest part of the house, or alternatively, in a central location, which is what I've done here. Since moisture rises, the first floor is preferable. But you can hear the sound of it. It's not particularly noisy. It's the sound of a sort of small fridge. But we were finding it a little bit noisy to have outside our bedroom door on the landing. So, I got a 73050 by Ebac a year ago now, and I've been playing around with it ever since. But it's only recently, since I've understood the science of relative humidity and the significance of dew points, that I've been able to make sense of the data I've collected. Let me tell you a little bit more. I've done a lot of data gathering exercises over the last year, but the most comprehensive have been over two two-week periods this Christmas 2019. Using the thermo-hygrometer every morning, I've recorded the relative humidity downstairs, the temperature inside, relative humidity outside, the temperature outside. I've sucked all the condensation off the windows using the Karcher vacuum, carefully measured what's left in the reservoir, and I've entered the Ebac unit every morning again, measuring the water extracted. And what I found out has been quite interesting. The first point, as you'd expect, is that the Ebac has been extracting consistently high volumes of water, typically between one and a half litres and two litres a day. Although for reasons I'll elaborate on, that water extraction rate is not correlated to the condensation I've had on my windows. The second point to make is that the relative humidity level in the cottage, since we started the trial, has been slowly decreasing, as you'd expect, as a smart control system started to do its work, and the water extraction had an effect on the relative humidity, and running consistently less than 50%, where safely within the comfort zone. So, I don't have a relative humidity problem in this house, which is a great achievement. But I do have a persistent condensation problem, as you've seen on both our single glazed windows and also in the corners of our double glazed windows. Initially, I was really confused and disappointed by this, but I've since realized that we're like here. You've got single glazed windows. There is very little you can do, even when you've got consistently low RH values around the house, there is very little you can do to stop the relative humidity close to the glass from reaching dew points. And what I'll come on to a couple of steps you can take shortly.
So, the one thing you can be sure of, which is obviously no surprise, is that the outdoor temperature is directly related to the condensation on our windows. Just look what happened to the condensation on day 5 when the temperature outside dropped to two and a half degrees Celsius, and on days 13, 14, and 15 where it was near freezing. And this is not a failure of the dehumidifier. Again, it's down to that pesky dew point. On day 4, taking all factors into consideration, the dew point was approximately 8 degrees Celsius. So, with an outdoor temperature of 8.3, there was very little condensation. On day 5, however, the outdoor temperature plummeted to two and a half degrees, and with a dew point again of around 8 degrees Celsius, it's no surprise we had 175 millilitres of condensation. So, clearly, installing double glazed windows is going to help no end with your condensation issues. But it's not all bad news. If you've got single glazed windows like I have, it dawned on me during this trial that the whole reason why heat exchange systems, PIVs, are so good is because they thrive on circulating the air around your home. And of course, when you go to bed at night and shut your curtains, you're denying any circulation in that space between the curtains and the window. So, of course, even with plenty of heating in the house and low relative humidity levels like I've got, we're not giving our windows any chance to stay free of condensation with the curtains shut, because what we're doing is we're denying the chance for that drier, warmer air to keep flushing over the window surface to prevent the relative humidity rising to dew point. And to illustrate this, on a couple of evenings, like for example, day 15 of the trial, I left the curtains open, and the effect was dramatic. Condensation plummeted from 210 millilitres to zero overnight. And just to finally illustrate the point, this morning, final day of filming, 3.6 degrees outside, and an insignificant amount of condensation on this window where we had the blinds open all night. And then on the same wall, just a few feet away, where our bay's curtain shut all night, loads of condensation. Now, that's probably not exactly what you want to hear, as it's not particularly practical advice to say leave your curtains open, particularly with privacy issues and also trying to keep warm at night. But I hope that gives you a bit more of an insight into why the condensation is forming, so that it gives you some ideas and maybe a bit of a strategy as to how you can fix your problems.
So, what about the second two-week trial when I have this Ebac dehumidifier switched off? And weirdly, the relative humidity levels stayed stubbornly low, as did a lot of the other data. The honest answer is, I don't know why this should be the case. But I think, in conclusion, I've got a pretty well-ventilated house with leaking windows, but also the lifestyle measures that we put in place, as described earlier on in the video, to keep condensation, to keep moisture down. However, there are other factors at play as well. We've got a brick and dirt floor immediately below this carpet. I've got a basement that's not properly insulated. So, this has not been the perfect trial for this unit, where typically you want a better sealed space for it to operate at maximum efficiency.
So, the third header in my solutions list was insulation. And I will just quickly mention that because it fits in with everything we've been discussing. We have insulated now most of the upstairs rooms in our house to really good effect with insulator that plasterboard. And what that has done is it's warmed up the wall, it's stopped it getting to that dew point that we discussed earlier. And as a consequence, walls that used to have a lot of mould in them no longer do. However, I would say to you, I would urge you to think of insulation as part of your moisture reduction strategy rather than the answer to it. You need to tackle those relative humidity levels, get them down first, and maybe see the insulation as an additional measure to make your house easier to heat. Because if you just do the insulation, you're potentially masking the problem, applying a sticking plaster to it rather than resolving it.
So, that's it for today. I've gone for far too long, over 24 minutes. I'm sorry about that. I was just wanting to make the video as comprehensive as possible for you. And I hope it's given you some good ideas as to how to resolve your problems. Get yourself one of these. It's an absolute lifesaver where you have got condensation you can't sort out. I'll put post links to that as well as everything else in the description at the end of the video, which, don't forget, on your smartphone, you can access by clicking on the little arrow, and on your computer by clicking the show more button. If you liked today's video, do please click on the like button below. And if you're new to my channel, it means so much to me if you were to subscribe. You can do that by clicking on the link here. Thanks, and see you soon.