myke
Well-Known Member
With all this cold my NG house furnace is running so much my humidity has dropped a lot.
Cold and high RH. Buy an extra Heater to solve both issues?
- Thread starter greenops
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thumper60
Well-Known Member
yup i have hot air furnace very dry when it gets 10-20 below zero step out on the deck in the morning sounds like a gun going off with the pop.
thumper60
Well-Known Member
Yup furnace will dry stuff out quick not so much with a boiler.
ttystikk
Well-Known Member
And this is why they work so well.
ttystikk
Well-Known Member
If you look at an air conditioner, it's actually producing more heat than cooling. On the cold side, it might even be condensing water but as the air warms up, its RH falls.
A dehuey is basically an AC unit you leave in the room, rather than sticking the hot end outside of it. The reason it dehumidifies has little to do with the trickle of water running out of it but rather the heat it's rejecting out the back of the unit.
Gonna disagree with u on that one; its true that if the moisture content of the air remains the same and temps increase that the RELATIVE humidity will decrease...and if temps fall then RELATIVE humidity will increase.
You are wrong on dehumidifiers.
They are essentially air conditions, that is correct. The difference is that the a/c part of a dehu serves to cools a coil which allows moisture from the room to condense and collect on the coils, this is how moisture is removed from the room.
Yes any heater, including a dehumidifier will decrease relative humidity simply by increasing the temp(assuming of course that the moisture content of the air remains a constant) that is not how a dehu removes moisture. It actually removes moisture.
Some commercial dehumidifiers even have the option to duct the heat out of yhe space being dehumidified.
thumper60
Well-Known Member
True the water that comes out of mine is ice cold.
Bukvičák
Well-Known Member
You need both coils: condenser and evaporator to get it work. Their names comes from in which stage the refridgerant is. AC is suppose to cool thats why you exhaust the air which goes through condenser out. Thats the case of portable units. If you have minisplit than you just have your condenser in your outside unit. AC dehumidify as well. Dehu is not suppose to cool down and they work better with higher temp thats the reason why the air is not exhausted oustside rather than expelled back in the room. You are basically right about temp/RH relationship but You should take into consideration that you have plants in your room. But it has been said, higher temps means higher transpiration so adding heater into the room wont lower your RH thats BS!
HydroKid239
Well-Known Member
A heater won’t bring the RH down, but it can be used to bring you to a better vpd. If you are staying around 65%, bring temps up to about 25-26c.
A good rule of thumb for dehumidifiers: It should have a capacity equivalent to the amount of water you put into your plants.
For example, if you have 5 plants and each drinks 2 liters of water, that is 10 liters in total, so you need a dehumidifier with a capacity of 10l a day, at least.
Plants transpire 90% of water so you want to dehumidify all of it. Of course the transpiration happens over a course of few days so you might think of cutting the capacity in half for each day, but you also need to dehumidify the natural humidity in your room that doesn't come from the plants, that's why you need that extra capacity. And also better safe than sorry, having a stronger dehumidifier won't hurt. If anything, it will dehumidify quicker and you can turn it off sooner, saving electricity over the long run. They can be noisy like fans so it's better to run a strong dehumidifier for short periods than running a weak dehumidifier all day.
Personally i have this one: https://uk.trotec.com/products-services/machinery-homecomfort/dehumidification/condensation-dehumidifier-of-the-ttk-series/ttk66e/
I still haven't used it properly with my grow so i can't suggest exactly this product, but just to give you an idea.
I tried it though and it works well, it's not too loud either. You can set the desired humidity from 35% to 80%, you can put a hose to drain water constantly without filling the main reservoir. Usually when the main reservoir fills, the dehumidifier stops, but with a hose extension it doesn't stop.
You can also change the fan speeds so it can be quiet on low setting. And it's pretty powerful too, 24l/24h.
I'll be also growing in bedroom just like you, and i bought a much stronger dehumidifier than needed so i don't have to deal with noise as much, running it for short periods of time. It's a very humid area where i live so i need to dehumidify not only the transpiration from the plants but also the room itself. Room is around 20m2, i'll have 6 plants in small pots that will take around 2 liters of watering. So in theory i should've gotten a 12l/24h dehumidifier, but the price, wattage, and noise are not that much different between the different capacities so why not go for the more powerful one.
A heater will surely lower some humidity, but not much, maybe 10% from my experience. But if i'm not mistaken, that evaporated humidity still needs to go somewhere, so once you turn off the heater without venting/opening windows, the humidity would quickly rise again. But i'm just guessing, i could be wrong.
Also AC units dehumidify only when cooling, but not when heating. Some AC units have a built-in dehumidifier though.
For example, if you have 5 plants and each drinks 2 liters of water, that is 10 liters in total, so you need a dehumidifier with a capacity of 10l a day, at least.
Plants transpire 90% of water so you want to dehumidify all of it. Of course the transpiration happens over a course of few days so you might think of cutting the capacity in half for each day, but you also need to dehumidify the natural humidity in your room that doesn't come from the plants, that's why you need that extra capacity. And also better safe than sorry, having a stronger dehumidifier won't hurt. If anything, it will dehumidify quicker and you can turn it off sooner, saving electricity over the long run. They can be noisy like fans so it's better to run a strong dehumidifier for short periods than running a weak dehumidifier all day.
Personally i have this one: https://uk.trotec.com/products-services/machinery-homecomfort/dehumidification/condensation-dehumidifier-of-the-ttk-series/ttk66e/
I still haven't used it properly with my grow so i can't suggest exactly this product, but just to give you an idea.
I tried it though and it works well, it's not too loud either. You can set the desired humidity from 35% to 80%, you can put a hose to drain water constantly without filling the main reservoir. Usually when the main reservoir fills, the dehumidifier stops, but with a hose extension it doesn't stop.
You can also change the fan speeds so it can be quiet on low setting. And it's pretty powerful too, 24l/24h.
I'll be also growing in bedroom just like you, and i bought a much stronger dehumidifier than needed so i don't have to deal with noise as much, running it for short periods of time. It's a very humid area where i live so i need to dehumidify not only the transpiration from the plants but also the room itself. Room is around 20m2, i'll have 6 plants in small pots that will take around 2 liters of watering. So in theory i should've gotten a 12l/24h dehumidifier, but the price, wattage, and noise are not that much different between the different capacities so why not go for the more powerful one.
A heater will surely lower some humidity, but not much, maybe 10% from my experience. But if i'm not mistaken, that evaporated humidity still needs to go somewhere, so once you turn off the heater without venting/opening windows, the humidity would quickly rise again. But i'm just guessing, i could be wrong.
Also AC units dehumidify only when cooling, but not when heating. Some AC units have a built-in dehumidifier though.
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ttystikk
Well-Known Member
It's called RELATIVE humidity for a reason, and that reason is because the ability of air to hold moisture changes with temperature. The warmer it is, the more moisture the air can hold, therefore RH falls unless more moisture is being added.
Bukvičák
Well-Known Member
The theory is correct. Practice is like this: you have grow space with some temp/RH. You rise your temp while amount of the water in the air stays the same (assuming there is no living biomass in there) so your RH drops thats fine. But once you have plants there and you rise your temp you are actually also rising VPD which means that the amount of water respired by the plants is also higher. Without removing the water from the air the effect is completely opposite than and you end up with hot and humid environment and thats much worse than cold and humid. Dehu’s work can not be replaced by adding a heater…
ttystikk
Well-Known Member
Strange chart?
And there's more to it than that, by far. Small plants don't create much RH, lots of big plants definitely do.
I WAS talking about theory.
VPD isn't a cause, it's a range of ideal conditions. By the way, that range is more humid the warmer it is. Maintaining proper VPD is most important if you're supplementing with CO2.