Humidity Problems In Your Home Recording Studio
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HVAC is certainly the hardest part of building a soundproof home recording studio. An often overlooked part of your heating and cooling system is humidity control. In this article we are going to go over the best practices when designing your HVAC system to keep your relative humidity in the ideal range.
1) What is the ideal relative humidity?
This is a debatable topic, but most books I have read and websites I researched said that 30-50% relative humidity is ideal. (Lennox)
2) Why do we use the term "relative" when talking about humidity?
You might be wondering why we use the term "relative" when talking about humidity. The reason is that humidity is the amount of moisture air can hold at any point in time. The amount of moisture air can hold is not constant. It is dependent on the temperature and air pressure. However, the amount of water in a room does not change with temperature and air pressure.
For example, when you blow up a balloon you put both air and some water vapor from your mouth. Now if you put that balloon in the freezer the balloon will shrink because the air is colder, but the amount of water droplets in that ballon will not change. This is similar to how relative humidity works in your studio.
3) Where does humidity come from?
So most humidity issues will come from people exhaling in your studio and fresh air being brought in from the outside. In the winter months your studio may be too dry and in the summer months your studio may be too wet depending on your climate.
4) How do you get the right humidity in your room?
This is the main question and there are a couple answers depending on your HVAC system. First, let's learn about sensible cooling loads and latent cooling loads.
Sensible cooling loads: measure the ability of your unit to cool the air in your studio.
Latent cooling loads: measure the ability of your unit to remove moisture from the air.
Now calculating those loads is best left up to an HVAC specialist or contractor with experience in HVAC installs. However, you still can ask if the latent cooling load with be adequate if you have an ERV pumping in X amount of air per minute and X amount of people in your studio.
Some contractors will oversize units either to make more money or simply out of ignorance and this can cause problems with your latent cooling load. The reason is that a unit that is too big for your home or studio will run in short bursts. This starting and stopping of the system does not give the unit enough time for the coil to reach dew point and for the air to have enough time to cycle the room through complete air exchanges. (Gervais, 139). This means the air will not pass over that coil and drip into the drip pan removing moisture from the air unless the unit runs for a long enough time.
All in all, it is important to communicate with your HVAC tech or even a couple different ones to get opinions on how big your unit should be to properly remove moisture from your house/studio and keep the relative humidity between 30-50% year round.
5) What about mini-splits?
I am a big fan of mini-splits and energy recovery ventilators working together to heat, cool and provide fresh air in your studio without adding any unwanted noise. The downside to this system is the humidity control can be a bit tricky.
Now, my Mr. Cool mini-split does have a "Dry" mode, which does help remove moisture from the air. In dry mode the unit will end up cooling your room a bit more to help control humidity. This can be great, but I have found that sometimes the room feels a bit too cold to get down to lower humidity levels.
The ERV will bring in fresh air from the outside, but on super wet days here in Nashville that air is still fairly humid when it enters the studio.
6) Use a dehumidifier
It might seem overly simplistic, but you can use a dehumidifier to help with any extra humidity problems you may be experiencing. Yes, these units might not be whisper quiet, but they can run at night or when you are not recording. You can also design your studio to have an air exchange room where the room next to the studio has a dehumidifier and air conditioner in it and the air is then sent into your studio room. This is not always possible, but it does allow for quiet in your studio at all times regardless of humidity issues.
Conclusion
Humidity can be an issue depending on your climate and time of year. The main goal is to keep relative humidity between 30-50% year round. Remember to properly size your HVAC unit to achieve proper latent cooling loads. If you need some extra help you can always run a dehumidifier when you are not recording to help remove moisture from the air.
Works Cited
Gervais, Rod. “Chapter 7: HVAC Design Concepts.” Home Recording Studio: Build It like the Pros, Second Edition, Course Technology PTR, 2010.
“Three Signs Your Home Has Poor Indoor Humidity.” Lennox, 3 Mar. 2020, www.lennox.com/lennox-life/comfort-matters/getting-comfortable/three-signs-your-home-has-poor-indoor-humidity#:~:text=The%20ideal%20relative%20humidity%20for,of%20moisture%20it%20can%20contain.
