Cooling
Ask most people what air conditioning does and they will say it makes a room colder. True enough, but it is only half the story. A good system also pulls moisture out of the air, and in a damp climate like ours that is often the part that makes a home feel genuinely comfortable. Reducing humidity does as much for how a room feels as dropping the temperature, and it brings real benefits for the fabric of the house too.
We fit systems all over the North-East and this is one of the most underappreciated things they do. Here is the science made simple and why it matters more than you might think.
Our climate is the reason it matters so much here. We get plenty of mild, grey, humid days that are not hot enough to want the cooling blasting away but are heavy and close indoors, and we have housing that holds moisture well. That combination is exactly where controlling humidity does more for everyday comfort and for the health of the building than chasing a lower temperature ever would. Once you understand what is going on, you will find yourself valuing the drying as much as the cooling.
The science, kept simple
Warm air can hold a lot of moisture. When that warm, humid air is drawn across the cold indoor coil of an air conditioner, it cools down, and cool air cannot hold as much water. The surplus moisture condenses out onto the coil as droplets, just like the water that forms on the outside of a cold glass on a warm day. That water runs off the coil, collects in a tray and drains safely away.
So every time the system cools, it is also drying the air. The dry, cooled air blows back into the room and the moisture leaves through the drain. You do not have to do anything to make this happen, it is simply how refrigerant cooling works. The warmer and more humid the air going in, the more water the system pulls out of it.
It can genuinely surprise people how much water comes out. On a muggy day a unit working a busy room will pull litres of moisture out of the air and send it down the drain, water that would otherwise be hanging in the room making it feel close and settling on cold surfaces overnight. That is moisture coming off breathing, cooking, showers, drying washing and simply from damp outdoor air finding its way in. All of it is quietly removed in the background while the unit does its main job.
Why lower humidity feels so much better
Humidity has a huge effect on comfort, often more than the thermometer suggests. A room at 24 degrees with dry air feels fresh and pleasant. The same room at 24 degrees with high humidity feels close, sticky and oppressive. That is because your body cools itself by evaporating sweat, and when the air is already full of moisture that evaporation slows right down, so you feel hotter and clammier than the actual temperature warrants.
This is why a dehumidified room feels comfortable at a higher temperature than a humid one. By taking moisture out, air conditioning lets you feel cool and fresh without having to crank the temperature right down, which is kinder on both comfort and running costs. The feeling of relief when you walk into a properly conditioned room on a muggy day is as much about the dryness as the coolness.
There is a comfort point worth knowing. For most people a relative humidity somewhere in the middle of the range, neither bone dry nor saturated, feels best and is healthiest to live with. Air that is too damp feels heavy and encourages mould, while air that is extremely dry can feel harsh. A well run system keeps you in that comfortable middle band rather than at either extreme, which is part of why a conditioned room feels pleasant to be in rather than just cold.
Dry mode
Most systems have a dedicated dry mode, usually shown by a water drop symbol on the handset. In dry mode the unit prioritises pulling moisture out of the air over hard cooling. The fan runs gently and the system focuses on wringing the humidity down rather than dropping the temperature sharply.
It is ideal for those muggy, overcast days that are not especially hot but feel heavy and close, the sort we get plenty of. The room does not get cold, it just feels lighter and fresher as the dampness comes out of the air. Dry mode is also gentle and economical, so it is a good option overnight or when you want comfort without a chill.
A lot of people never try dry mode because they do not realise what it is for, and then wonder why straightforward cooling leaves the room a little too cold on a mild damp day. Once you know it is there, it becomes one of the handiest settings on the handset. It is particularly good in spring and autumn, when the weather is not warm enough to want cold air but the house still feels clammy, and for drying out a room after a lot of cooking or a bathroom full of steam. Give it a try the next time it is grey and sticky rather than hot and you will feel the difference.
- Muggy days. When it is warm and sticky rather than genuinely hot.
- Overnight. Takes the clamminess out without making the room cold.
- Shoulder seasons. Spring and autumn days that feel damp indoors.
Fighting condensation, damp and mould
This is where dehumidification earns its keep beyond comfort. Damp air is the root cause of condensation, and condensation is what leads to black mould around windows, in corners and behind furniture. When the moisture level in the air is kept down, there is far less water available to settle on cold surfaces, so condensation and the mould that follows it have much less chance to take hold.
For homes that suffer from steamed-up windows, musty smells or recurring mould patches, controlling humidity is a big part of the answer. Air conditioning is not a cure for a leak or rising damp, which need fixing at source, but for everyday condensation driven by moist air it makes a real difference. Drier air also means the room smells fresher and feels healthier to be in.
Bedrooms are a common problem spot. We breathe out a surprising amount of moisture overnight, and in a cool bedroom with the curtains drawn that moisture settles on the cold glass and runs down to the sill, where it feeds mould along the frame and in the corners. A system that keeps the air drier through the night gives that moisture far less chance to condense, which is why controlling humidity often sorts out streaming windows that no amount of wiping down ever cured. The filtering the unit does on top helps keep the air cleaner too, which many people with hay fever or dust sensitivity notice.
Protecting your home and belongings
Persistent damp is not just unpleasant, it is damaging. Over time it can affect plaster, decoration, soft furnishings and timber, and it is bad news for anything that does not like moisture. A home kept at a sensible humidity level is a home that looks after its contents better.
- Decoration. Less risk of mould staining paint and wallpaper.
- Soft furnishings. Curtains, carpets and upholstery stay fresher in drier air.
- Timber and furniture. Stable humidity is kinder to wood over the long run.
- Stored items. Books, instruments and electronics all prefer dry air.
For some of our customers, especially those with a music room, a home office full of equipment or a room that has always felt damp, humidity control is the main reason they fit air con in the first place. The cooling is almost a bonus.
Humidity versus temperature comfort
It is worth understanding that comfort is a balance of the two. You can be perfectly comfortable over quite a range of temperatures if the humidity is sensible, and deeply uncomfortable at a moderate temperature if the air is saturated. That is why simply turning the thermostat down is not always the answer to a room that feels unpleasant.
Often the better move is to bring the humidity down and let the room feel fresh at a reasonable temperature rather than overcooling to fight the stickiness. A well set up system does both at once, and once you learn to read your own comfort you will find you reach for dry mode as often as full cooling. The aim is air that feels light and easy to breathe rather than air that is simply cold.
This balance is why a decent air conditioning system beats a standalone dehumidifier for all-round comfort. A plug-in dehumidifier only dries the air and, because of the way it works, it tends to warm the room slightly as it runs. Air conditioning dries the air while cooling or gently warming it as you choose, under one control, so you get the humidity and the temperature right together instead of fixing one and upsetting the other. For a room you actually live in, that joined-up control is what makes it feel properly comfortable rather than merely less damp.
The drainage side of things
All that moisture the system removes has to go somewhere, and this is a part of the installation that quietly matters. The water collected from the indoor coil is piped away through a condensate drain, usually run to a suitable outside point or drain. On the outdoor unit in heating mode you will sometimes see water too, which is normal.
A good installation gives the condensate a clean, reliable path away with the right fall so it drains properly and does not sit or back up. A poorly run drain is one of the common causes of an indoor unit dripping, so it is worth having done properly from the start. A blocked or badly fitted drain can cause leaks and damp, which rather defeats the purpose, so it is part of what we get right on every job and check at a service.
Where there is no convenient drain to fall to by gravity, a small condensate pump can lift the water to a suitable point, which gives us far more freedom over where the indoor unit can go. The main thing is that it is planned properly at the design stage rather than bodged on afterwards. A little care over the drainage is the difference between a system that quietly removes moisture for years and one that leaves a damp patch on the wall, so it is well worth getting an experienced installer to set it up correctly.
Talk to Air Con North
If your home feels damp, sticky or prone to condensation, the right air conditioning system will cool, filter and dehumidify it, and keep it fresher and healthier all year. We design, supply, install and maintain systems for homes and businesses across the North-East, from Sunderland and Durham to Newcastle, Gateshead, Middlesbrough and Carlisle, with over 25 years behind us. Call us free on 0800 246 5430 for a no-obligation survey and we will talk you through what would work best for your rooms, including getting the drainage and controls right so it performs properly for years.
