Dear Reader,
Are you sitting inside in stagnant polluted air? Maybe the cat just hurled, maybe someone put fish in the microwave again, maybe someone brought some paint inside and didn’t check the label to make sure it was safe for breathing. 😬
It’s time to move air! Specifically – fresh air into your space and bad air OUT.
How can we tell IF air is moving? Air is invisible, so this can be tricky. Here’s a list of ways to get an idea of how air is moving through your space (or if it is moving at all):
- A smoke pencil / smoke pen. This tool gives off a small stream of smoke that will move in the direction the air is moving. Faster air will carry the smoke horizontally and stagnant air will allow the smoke to rise vertically.
- Blowing bubbles. Bubbles will travel the way the air is flowing.
- A thin strip of paper (¼ – ⅛ inch, or about ½ centimeter) taped to a steady surface. This is a classic way to figure out if air is blowing through a vent or window. The end of the paper will drift in the direction that the air is flowing and drift more if the air movement is stronger and not at all if the air is relatively stagnant.
- If you want to be more precise / official, you can use an anemometer, a device that will give you precise readings of air flows. Make sure to get one that is designed for lower air flows and use it as directed.
When you’re inside a building and need to get air moving faster, you need to amp up what they call in the “biz” the ACH, or Air Changes per Hour. ACH equals the number of times in one hour the air in a certain space is completely replaced with fresh air.
Here are ways to get air moving:
- Push it. Imagine a fan.
- Pull it. Imagine that same fan pointed the opposite direction.
- Leverage temperature changes since hot air rises and cool air sinks. Imagine a hot air balloon rising high above the cooler air on the outside of the balloon.
- Leverage pressure changes since air will move from higher pressure to lower pressure spaces. Imagine air escaping from an inflated rubber balloon.
To figure out the best ways to get air moving in a particular space, look around and find out:
- Is there a way that air is currently pushed into our out of the space? For example, is there a vent that is blowing air into the space or pulling it out? (You can use one of the methods above to tell if air is coming in or being pushed out.)
- What ways can air get into or out of the space? For example, windows, open doors, cracks under doors or around windows, exhaust fans that get turned on by a switch, range hoods that take air out of the space, etc.
- What is the temperature inside the space and outside the space? We’re getting an idea here of how different the temperature is! Remember, hot air rises and cold air sinks, so the bigger the difference in temperatures, the quicker you may be able to get the air to move.
- Is there anything happening in your space that might cause the pressure to be different than the outside air pressure? For example, if an exhaust fan is running, this will be moving air out of the space causing the pressure in the space to drop. When pressure in the space drops, as soon as an opening is made, air will enter through that opening.
Now, it’s time to move air! This will take some experimentation and your strategies may need to vary from space to space within the same building.
Free Ways to Move Air
With zero budget for fans, electricity or tools, we can still harness the power of temperature and pressure differences on opposite sides of openings like windows and doors to get air moving!
- Start by opening a single window or door to the space. See how much airflow you can get going. If the temperature or pressure differential is large, that may be all you need to do for a good breeze.
- To increase flow, experiment with different combinations of open windows and doors. If you have windows on opposite sides of a room, you may be able to get a crossbreeze going. Similarly, you might have luck with a window across from an open door to a different space in the building.
Low Budget Ways to Move Air
- Add a window fan. It will give you more air-moving power and also a greater level of control over how much air you move through your space.
- Add two or more window fans. Experiment with one blowing air in from an opening and one blowing air out of a different opening.
- If your space has an exhaust fan (like in a bathroom) or a kitchen range hood that takes air outside of the building, you can run it for a short period of time to pull air out of the space. That air will backfill from wherever your air enters the space (like an open window.) These types of exhaust systems are often designed to run for a shorter period of time, so it’s best not to leave them on constantly.
- If your space has a ventilation system and you know how to work it – you can turn it up to move more air through the space for a period of time.
Important Notes:
- Check the AQI outside (US air / international air) to make sure air is actually relatively unpolluted before moving it into your space. Sadly there are many parts of the world where air outside is not “fresh” all the time anymore. You will want to limit that air entering your space when it is especially polluted (unless of course you have an excellent air filtration system.)
- While not a focus of this article – it is generally good to be mindful of energy use. Certain energy generators (e.g., coal powered power plants) produce air pollution. Fresh air from outside may need to be conditioned (e.g., heated, cooled, etc.) when it is brought in a building, which requires energy. Experiment to find a good balance of fresh air brought into your space, and energy required to condition it.
Enjoy your fresher air!
M