3044: Humidifier Review

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Humidifier Review
They should add a little sticker that certifies that the humidifier supports water conservation, but in the sense of energy conservation or momentum conservation.
Title text: They should add a little sticker that certifies that the humidifier supports water conservation, but in the sense of energy conservation or momentum conservation.

Explanation[edit]

Ambox notice.png This explanation is incomplete:
Created by a 101% EFFICIENT TOASTER. This page was clearly autogenerated by an AI that does not understand the comic nor humidity engineering. I tried to improve the first paragraph. Do NOT delete this tag too soon. If you can address this issue, please edit the page!

This comic shows a review of a humidifier, with the reviewer complaining that it uses too much water to increase the humidity of the room to 45%. On the face of it, someone buying a humidifier for the first time might not have an understanding of how much water the device needs, and could be taken by surprise (possibly when their water bill arrives, or by the number of times they are required to manually refill its reservoir). The review in the comic has taken it a step further, voicing their complaint as a flaw in this specific humidifier and wishing another model could somehow achieve the same results with less water.

A humidifier works by evaporating water from a tank, causing the air around it to become more humid. The law of conservation of mass states that the amount of matter in any closed system must stay constant, with the corollary that the amount of any substance in a system can only increase by introducing more, or by generating the substance from existing matter in the system. The humidity level in a given space is a function of the amount of water vapor in the air (in comparison to the saturation levels of water vapor at the given temperature and pressure). Which means that water must be added in order to increase humidity levels under any given conditions.

Unless the humidifier is leaking liquid water (which would likely be detected and mentioned), the amount of water the humidifier "consumes" is the same as the amount of water vapor added to the air (unless the machinery is made by Beret Guy). The amount required depends on the relative humidity level (which is set by the user), air temperature and pressure, the rate of air movement out of the room, and any other sources of humidity present. The humidifier has no control over any of those variables, which means that any humidifier maintaining the same humidity levels under the same conditions must consume the same amount of water. This is not a comment on the quality or design of the specific humidifier, and blaming it on the device makes no sense. The humor is thus at the expense of people who don't understand the requirements of their appliances (or other hypothetical services) and complain in ignorance about the impossible not being made possible for their convenience.

In principle, a particle accelerator could be used to create protons from energy, either directly, or indirectly as a product of the decay of other particles. Protons are hydrogen nuclei, and could be reacted with oxygen from the air to create water. However, such devices are not conveniently small, consume vast amounts of energy, involve dangerous and inconvenient radiation and magnetic fields, and generate a great deal of heat which would decrease the relative humidity. Thus, they are not a practical method of increasing humidity in a room.[citation needed]

Other examples of commonly-used, commonly-reviewed household devices whose operational efficiency is limited by the laws of physics themselves include resistive heaters, such as space heaters and electric kettles. Resistive heaters convert electricity directly into heat with 100% efficiency, and so the amount of power they consume is directly dictated by the amount of heat they're required to produce. Similar to the humidifier, complaining about a specific resistance heater drawing too much power is unfair, since any heater working on the same principle would draw the same amount of electricity to do the same job.

By contrast, coolers and heaters using refrigeration cycles, such as air conditioners, refrigerators, and heat pumps, can vary in efficiency, and therefore in the amount of power consumed for a given task. There is a maximum possible efficiency dictated by thermodynamics, but different designs may be farther away from this ideal efficiency, so the cost of running them may be a reasonable criticism.

Reviews which indicate the ignorance or gullibility of the reviewer, or which indicate the vindictive nature of the vendor, are a common theme in XKCD.

The joke in the title text is based on different senses of the word "conservation". To most people this refers to reducing wasted use of some material, e.g. "water conservation" means avoiding waste of water. But to physicists, it means that some quantity in a system stays the same; for instance, conservation of energy means that energy can neither be created nor destroyed. For many years, most appliances have had Energy Star stickers that indicate their impact on the environment; by adopting the physicists' sense, they can trivially say they support water conservation.

Transcript[edit]

[A product review is shown. At the top left is a small drawing of a humidifier within a rectangle. To the right of that rectangle the product name is given. Beneath this is is a line of illegible text, followed by a shorter line of illegible text within a rectangle.]
HydroPro Humidifier
[Then below this is a header above a horizontal line that separates the above from a small close-up drawing of Hairy in a circle to the left with two lines of illegible text to his right. Below this is his review (3/5 stars) with a heading and his review text below:]
Reviews
★★★☆☆ Good but inefficient
It keeps the humidity at 45% pretty well. I'd give it 5 stars if it didn't use so much water.
[Caption below the panel:]
My favorite reviews are the ones that penalize products for not violating the laws of physics.


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Discussion

Somehow, the text here makes me think of the air-source heat pump equivalent, i.e. Why shouldn't it be the case that humidifiers condense outside air and suck the water out of it, and then pump that water into the conditioned space and re-disperse it? Of course, the obvious answer is that doing so would be frightfully expensive and entirely unnecessary given the cost of that kind of condensation compared to the cost of water. And, of course, the capital cost for the minor plumbing to install a domestic water line to the humidifier is going to be far smaller than the capital cost of a heat pump apparatus (or whatever) to generate condensation outdoors and then pump it into the conditioned space. JohnHawkinson (talk) 00:13, 30 January 2025 (UTC)

Also it would still need that amount of water, just that the operator doesn't need to add it manually. --Lupo (talk) 12:43, 30 January 2025 (UTC)
It'd be a "fun" project to capture the condensate from a household ASHP in order to fill a household humidifier tank automatically, for all the wrong reasons. At the moment, ASHP condensate tends to be sent directly into the drainage system, so it's "free" water for the humidifier, you "just" need to store it from the damp months to the dry months. Farnz (talk) 10:42, 3 February 2025 (UTC)

This reminds me of the whole thing with the VTuber Sakura Miko where she was using a humidifier without knowing she had to fill the tank with water for at least a year 172.70.223.184 01:10, 30 January 2025 (UTC)

Related to that, just a week ago Sharp announced a humidifier collaboration with Sakura Miko, and as part of the PR they made a formal apology for "Not being able to use magic to make a waterless humidifier" 198.41.236.162 (talk) 02:01, 30 January 2025 (please sign your comments with ~~~~)

I'm waiting for the HydroPro High-Efficiency Electric Kettle™ which is connected to a heat pump to heat your tea water. 172.71.170.192 04:39, 30 January 2025 (UTC)

High-Efficiency Electric Kettle™ which is connected to a heat pump to heat your tea water You jest; but in the US we get hot water at the sink faucet. There is a push to do it all with heat-pumps, save a hundred bucks a year! (They say more, but I've compared our use.) But the heatpumps are $2K. A dumb resistor tank is $500. Payback is well in excess of 5 years. And it would make my cold cellar even colder, thus damper. --PRR (talk) 06:17, 30 January 2025 (UTC)
A heat pump water heater would (if properly installed) make the cellar colder and dryer. Essentially, it's air conditioning the cellar and that's what A/C does. In detail water will condense on the cold coils (giving up latent heat which helps heat the water) and the condensate should go down a drain reducing the amount of water in the cellar.162.158.62.107 16:02, 31 January 2025 (UTC)
Just install a dehumidifier. And feed the water that the dehumidifier into the water heater. Infinite hot water! Also, enormous electric bills. Also legionnaire's disease. RegularSizedGuy (talk) 06:22, 30 January 2025 (UTC)
All dehumidifiers and all humidifiers must be connected together for the ultimate harmony! (If there turns out to be a net need/excess, we can work out what to do... We probably have a whole load of piping leading all over the planet, by this time, so we can find the most optimal source/sink.) 172.70.162.33 13:32, 30 January 2025 (UTC)

Another device which is often getting negative reviews for not breaking laws of physics is car. Not only that, EU laws for 2035 are basically making against the EU law for a new car to not break laws of physics. -- Hkmaly (talk) 09:08, 30 January 2025 (UTC)

The only two transportation options that do not either break the laws of physics or ultimately prove either unfeasible or useless against carbon dioxide spiking and resulting anthropogenic climate change have five toes on each one. 162.158.42.87 15:34, 30 January 2025 (UTC)
Cycling burns about half the calories per mile as walking. Which one has the lower overall carbon footprint depends on a lot of factors, including the carbon created for food production, bicycle production, the lifetime and maintenance requirements for the bike, the health benefits leading to a longer life (and hence more carbon production) for the walker/rider, etc. But if you already have a bike, it's probably more efficient to ride than it is to walk. 162.158.62.169 17:59, 30 January 2025 (UTC)
Except that this isn't how humans work. Just because you reduce your calorie expenditure on transportation doesn't mean you reduce your calorie expenditure overall - it will just get expended somewhere else. Besides which, calorie expenditure isn't tied to calorie consumption. Even if you were able to reduce your overall expenditure, it would make no difference at all to your carbon footprint. To do that you'd need to reduce how much you eat (or change its composition).141.101.98.7 09:33, 31 January 2025 (UTC)
You would burn fewer calories if you cycled for a while (instead of walking) though. Maybe cycling a mile compared to walking it wouldn't really make any difference, but cycling 20 miles as opposed to walking that definitely would burn fewer calories. Walking 20 miles is already going noticeably over your regular calorie expenditure, which is going to require more food no matter what, so cycling instead would definitely require less food. Although the difference is probably not too big compared to what you would usually burn. Beanie talk 10:09, 31 January 2025 (UTC)
Be sure we're talking of the same things. Cycling twenty miles might be accomplished in an hour (allowing for sympathetic terrain/roads, bike and degree of fitness), with some effort and therefore raised metabolism, but should normally take less than two hours just by keeping the wheels turning at a decent rate. Walking twenty miles might be six to twelve hours of walking (including stops, which I don't bother to assume that the rider will take).
(...assuming you are physically/mentally capable of either. I regularly walk a nine-mile (rugged) path from A to B every week, taking about 3.5 hours unless I'm rushed (faster) or it is/has been raining (the 'direct' route gets muddy, either slowing me down or I divert by longer roadside routes around sections). For the purposes of the trip (for which I know I have a handy lift back), I know I have a reason to get there. (Ocasionally with a diversion to a handy geohash!) I probably wouldn't walk in a nine-mile circuit, without something to do at the extremities of the point. Even though I have walked 20+ miles, I'd need even more incentive. Meanwhile, I wouldn't go cycling for 'just' nine miles of circuit, that's a waste of time in the other direction. The pleasure of the ride (balanced with the effort of it, and preparing for it) means that 20 miles of no other purpose is at the lower end. But then I was brought up as a cyclist used to weekly 50+ mile rides via at least one cafe-stop, or similar. I know some people wouldn't/couldn't/daren't walk maybe half a mile (total) to the shops and back, or ride there. Others (not me!) will happily ride as fast as they can for 12 or 24 hours, or more, for their own reasons.)
...Anyway... Having saved enough time to have five hours for every hour of travel, you don't then flatline your activity and consider it done, but continue to exist. Even if that's vegging out in front of the TV. 20 miles on the bike should probably include the hours (and the meals) you spend pre- and/or post-trip, which map to the equivalent time you'd spend for the same walk without the bicycle. Also, as you might or might not also have the bike, whatever the reason you can't/shan't use it, hard to factor in the 'investment' carbon footprint for equipment you might or might not use, and which might amortise its 'cost' across an indeterminate number of actual uses. Much like you could have a car or any other vehicle but can only reliably compare fuel/charging costs, between alternative modes of travel, not usually the capital costs...
And even wear-and-tear-based upkeep is also a somewhat variable relationship. I wear out walking shoes within a year or two. I typically expect my bike tyres (and inner-tubes) to last much longer, but are subject to unrepairable damage at any time (I've had to deal with three separate punctures in a single day, before, luckily was easy to patch), which can badly mess with the running average.
The point being that comparison is difficult. And even if you're sure you've tied down what you mean, someone else may think it applies to their own (different) understanding. 172.70.91.246 17:47, 31 January 2025 (UTC)
You would burn less calories doing the cycling vs doing the walking, but you wouldn't burn less calories overall, because the calories you 'saved' would simply end up being burnt elsewhere. Even if you drove the journey, your overall calorie expenditure would still end up being the same. And in any case the food you consume doesn't tend to have much relationship to how much you 'require' — just because you walk rather than cycle doesn't mean you're then going to have a smaller portion at dinner — so how much you're burning is fairly irrelevant to carbon footprint.172.71.178.124 09:14, 3 February 2025 (UTC)
Actually, climate activists are trying to avoid mentioning it, but humans are TOTALLY significant producers of CO2 considering how many of them are. But mentioning it reveals the uncomfortable truth: we can't REALLY get to zero carbon dioxide emission. It's not realistic goal. -- Hkmaly (talk) 06:43, 3 February 2025 (UTC)
The idea isn't zero emissions, it's net zero - as much coming out as goes in.172.69.43.182 09:23, 3 February 2025 (UTC)
Exactly - the carbon you exhale was taken out of the air by plants through photosynthesis. You ingested it through food, it's part of Earth's natural cycle. The carbon from your car exhaust was taken from fossil fuels, which had been stored in the ground for many millions of years. It was (very slowly) taken out of the atmosphere a long time ago when the Earth was a much, much warmer place. And we are heading back to those temperatures by putting this underground carbon back into the atmosphere!162.158.203.27 15:48, 11 February 2025 (UTC)

Zero stars:

Dried out my house when I was already dehydrated

- BButton1869 PotatoGod (talk) 20:42, 30 January 2025 (UTC)

I'm not sure conservation of mass is the right law here. It would be possible to increase humidity without using water or violating the conservation of mass, such as by burning hydrogen. The relevant law here is the conservation of molecular quantity. Except . . . that's not a law (hence my hydrogen combustion counterexample). What's going on here is that you cannot change the amount of water without a chemical reaction, essentially by definition. So any humidifier that operates in a purely mechanical manner without reacting any chemicals will "conserve water" in this sense.

In the real world, every humidifier works this way, and it would rarely make sense to do it any other way. In fact, you are more likely to see oxygen made from water (e.g. in a submarine or space station) than vice-versa. However, if you have a natural gas furnace, that will produce water, and in principle, there's no reason that produced water could not be fed into a humidifier, thus saving on the water bill. Highly efficient furnaces capture the water without letting it out the flu, not because they want to salvage the water, but to increase efficiency. Still, the water is there, so this isn't a physically or even practically impossible demand. EebstertheGreat (talk) 01:28, 31 January 2025 (UTC)

"...a natural gas furnace, that will produce water, .....could ...be fed into a humidifier," There are gas appliances, cookers and room heaters, also gas clothes dryers, which can vent damp exhaust directly to the room. But even when I paid for water, I never fretted about the cost of humidity. And I already run a dehumidifier 7 months a year. And the hi-eff gas burners and the dehumidifier in a damp basement already force me to maintain a non-ignorable pump infrastructure to lift water out of the cellar. -- So unlike the joker in the cartoon, I am hyper-aware of my humidity.--PRR (talk) 04:39, 31 January 2025 (UTC)

"High efficiency electric rangetop!" High efficiency electric heating? Were other models making too much light? 172.70.179.132 (talk) 15:44, 10 February 2025 (please sign your comments with ~~~~)