Humidifier with humidity only at 40% after running overnight? After settling all four accounts one by one, it's almost certainly not a small machine

the end of October, as soon as it cools down, my Mijia ultrasonic humidifier was taken out from the shelf under the TV cabinet. The first night I worked diligently: before bed, I filled it up, set it to maximum, and set the target humidity to 55%. The next morning, I checked the thermometer by the bedside—38% had gone from 41%. After spraying all night, it rose by three points, but the radiator was half down. My child rubbed his nose again in the morning, and my first reaction was that this machine didn't work and I wanted to get a bigger one.

don't rush to place an order yet. Later, I laid out the account and did the math again, realizing that most of the time the machine had no issues, except for me who hadn't settled a single of the four accounts. Today, these four accounts are laid out one by one. If you check them once, there's a 90% chance you'll save money on a new machine.

first thing: which hygrometer to trust first

before settling accounts, there's a premise to mention first: the hygrometer itself. Right now, my living room has three devices that can read humidity: the humidifier sensor on top of itself, an electronic thermo-hygrometer I bought for about ten yuan by my bedside, and another similarly priced device on the living room wall. In the same room, at the same time, the three readings were 41%, 48%, and 53%, with a maximum difference of twelve points.

an electronic hygrometer costing just a few dozen yuan, if the error is within plus or minus ten percent, it's considered normal. The humidifier's own one needs to be discounted — it measures a small patch of air next to the machine, not the one at your bedside. So don't take the readings from a single hygrometer as imperial decrees; it's best to compare two or more readings and choose a middle value before drawing conclusions. A difference of three to five points doesn't matter, but if it's ten or so, it means at least one of them is making things up.

there's another concept to clarify: the percentage on the hygrometer is relative humidity, which is tied to temperature. With the same amount of moisture, the temperature inside the room drops as soon as the temperature rises. This is the root of the fourth account later, so remember it first.

First Ledger: Why can't you finish half a cup of water's work? First

do a paper account. My master bedroom is fifteen square meters, with a ceiling height of 2.7 meters, and the air inside is about forty square meters. Air at around twenty degrees Celsius can contain at most nineteen grams of moisture per cubic meter. Assuming the current humidity in the room is 30%, and you want to push it to 50%, the missing amount of moisture is 152 grams, which is about 150 milliliters, about half a cup of water.

my machine is labeled with a rated humidification capacity of 300 milliliters per hour. On paper, half an hour can finish half a cup of water. But the reality is, I surged all night and only managed to get three points. What's the difference? The missing three items were not included in the paper account. The first

leaked again, so let's explain the second part in detail. The second is quilts, curtains, and clothes. Dry fabrics absorb water more than you might think. When humidity rises in the room, they fill up first, and before that, the hygrometer can't move. The third is window glass. On late autumn nights, when the temperature is around ten degrees outside, when the room is humidified, the inside of the glass becomes the coldest surface inside. Moisture rises and moves toward the cooler spots, with some of it condensing directly onto the glass as droplets that flow away. On paper, it's half a cup of water, but in reality, you have to pour three or four cups in one night, and you have to be able to keep it up to count.

can also draw a useful tip from this calculation: the applicable area listed on the detail page, for example, the suitable area for 25 to 40 square meters, you can only know if you offer a 20% discount and another 20% discount. My unit is rated for 15 to 20 square meters, perfect for a 15-square-meter bedroom, but a 34-square-meter living room with dining room is just a drop in the bucket. It's not that the machine is stingy, it's that I use it beyond my standards.

second account for the air exchange: leaving a crack in the door means half a night of effort

you think closing the door is enough, but after a control test, I found out the door was even harder than I imagined. For two nights in a row, with no other conditions changed, only one thing was changed:

a door crack, a difference of seven percentage points in one night. The reasoning isn't complicated: the air inside the room is fluid. As soon as the door is left with a crack, the dry air in the hallway moves inward through the gap, and the steam the humidifier just adds to the air is diluted. It's just like pouring water into a bucket with a leaky bottom—if you keep pouring, the water level in the bucket just won't rise.

many people have the habit of leaving a gap in the bedroom door in winter to avoid stuffiness; Opening the window for ventilation in the morning is also a perfect habit. Neither of these things is wrong; the mistake lies in putting humidification and ventilation at the same time. My later routine was: close the door before bed and concentrate the humidification on the night, and open the windows for ventilation in the morning during the day when the humidifier was resting. Ventilation is changed to other times, humidification covers sleeping seven or eight hours, so neither is wasted.

if your home has a fresh air system, you need to pay extra attention. The fresh air flows inside the house 24 hours a day to dry the air. If your fresh air is running at full capacity, the small humidifier in the bedroom basically works for the fresh air. If the hygrometer can reach 45%, that's already its best effort. In this case, you either lower the fresh air by one level or accept the idea of replacing the machine with a larger humidification capacity; there's no third solution.

The third account of positioning: the machine's sensors can trick both ends

this account refers to position. Humidifiers and routers share exactly the same problem: if placed in the wrong place, the specs will lie. The idea of 'double scam' is something I came up with myself.

the first end, place the machine in a slightly dry spot near bay windows or window cracks. Its sensor is close and reads 38%, not reaching the 55% target, so the highest setting keeps spraying nonstop, the radiator drops a finger per hour, and the noise is loud. But where else inside the house? The moisture was already sufficient, and even the bedside was already at 58%, yet the machine was still foolishly spraying. This is the situation where the opposites of 'spraying nonstop' and 'not going up' both exist: the machine is right, the humidity is right, it's the position that causes the two to fight. This is how we set up the machine the first night at home. Putting the machine on the bay window saves space, basically letting it squat in the driest corner of the house, anxious.

second end is the opposite: the machine is placed in a spot with a spot like a wall or bathroom door where the floor has just been mopped. It reads 52%, just three points short of the target, so it simply downgrades to low gear or even stops. But the house was actually so dry that static electricity was emerging, and the humidity still wouldn't rise. Last time, I wrote about humidifier doesn't fog up mentioning that its sensor only recognizes a small patch of air nearby. This article covers both ends.

There are three rules for placement: place it in the center of the room, not against walls or windows; Raise it about one meter above the table; the fog is cool, sticking to the ground and easily soaking the floor; Don't let the fog outlet face people, appliances, or wooden furniture, and don't stuff it under the air conditioner vent—the mist just sprayed out will be blown all the way to the wall.

The fourth temperature account: the stronger the heating, the worse the humidity

which is the most counterintuitive record. My home uses centralized heating; the heater is burning at night and the warmest in the morning. One night, I stared at the hygrometer and watched the whole process: at 10 p.m., the room was 23 degrees, humidity 49%; At 7 a.m., the heating came back up to 24.5 degrees, and the humidity dropped to 44%. The moisture didn't decrease at all, but the temperature rose by one and a half degrees, while the humidity dropped by five points.

is what I mentioned at the beginning: the hygrometer shows relative humidity. The higher the temperature, the more moisture the air can hold. If the same amount of moisture is diluted, the percentage drops. At 18 degrees at night, the humidity looks like 62%. During the day, when it rises to 24 degrees, it's still just the moisture, leaving only 44%, dropping by more than ten points in between. So during the day, no matter how much you humidify, you can't count it; half the reason is that the temperature is just holding you up.

this account can't be challenged by physical laws, so we have to follow the schedule: place the main battlefield for humidification at night. Before bed, I turn the bedroom heater down by one setting, close the door, and set the machine to medium setting. With the low temperature and less moisture in the air, the same humidification rate works twice as efficiently, and the first thing I get up in the morning actually feels less dry. If the house is hot during the day, let it be—don't go head-to-head with the temperature.

By the way, if your home isn't using ultrasonic spray but a mist-free evaporative type, it can still be a bit slow for several days. It's not unusual to raise the temperature by three to five points a night. First, check if the radiator level drops and feel if the vent is wet before judging if it's working. Don't just focus on the hygrometer.

all four accounts are settled, it's time to pay the money

. Arranging these four accounts in order is a set of free checks:

• first compare two hygrometers and pass the reading threshold. Don't let a meter with a ten-point error slip into the trenches;
• calculate the area, and the machine's nominal applicable area is discounted by 20%, checking if it's over-the-line or forced;
• the night you test with doors and windows tightly closed, compared to the night you left a gap on the door, the difference is that the air is being used to your humidification;
• move to the center of the room, one meter high, away from the wind outlet, and observe for another night;
• after completing all four steps without moving a bit, then consider switching to a larger machine or a double machine, where the money is spent openly.

pay, there's also a gear level to refer to. I later recorded it on the details page: For a bedroom around 15 square meters, a 300 ml per hour is basically enough, provided the doors and windows are closed; For 20 square meters and above, you have to look at the 500 ml per hour range; In the living room, an open space outside 30 square meters, you either have to use a large set of 600 or higher, or just two units guarding separately, filling the area more thoroughly than a single big machine.

tens to hundreds of Here's an advanced trick: I plug my humidifier into the of a smart socket, and use the automated from the central gateway article to automatically power on when humidity drops below 40%. This setup is worry-free, but if you don't settle the four accounts, the socket diligently opens, the machine sprays diligently, and the hygrometer still doesn't budge—automation only manages the switch, not the area or door gaps.

my final answer was: the machine hasn't been replaced. I moved out the bay window and placed it on the cabinet in the middle of the room. Before bed, I closed the door tightly and turned the heater to a low setting. The next morning, the humidity meter stabilized around 55%, and my child's nose quieted down. Four accounts, three for free—do you want to do the math before placing an order?