Dan has been in the HVAC industry for 23 years with experience ranging from installation and service to sales and distribution.
What Is Cross Ventilation?
Cross ventilation is a natural or planned process where cold air displaces warmer air in a given structure. You can use this practice to save you money on utilities and breathe clean air — all without costing you a dime.
The principle of cross ventilation uses the relationship between heat and cold. Heat leaves an object or area to try raising the temperature of the cooler surrounding areas. When it moves, however, the last object/place is left with less heat. If the temperature outside is less than that inside your home, cross ventilation will be a breeze to do!
Two great ways to practice cross ventilation are:
- Opening windows opposite each other in a building
- Using a fan to direct the air
I'll go into more details of each method below, but you can already see that the process doesn't require special equipment or significant investment.
How to Cross Ventilate Naturally With Windows
The easiest way to cross ventilate naturally is to open the windows. It really is that simple. Ideally, you should open a few windows that are across from each other. Don't worry if this set up isn't possible in your home. Just make sure the open windows/doors aren't all located on the same side of the home.
The best method is having a breeze enter one window and exit directly from another one placed opposite the first. The air will find a way to the open areas even if windows are situated at 90 degrees from the inlet window.
Note: The amount of air moved is directly proportionate to the size of your inlet and outlet openings.
Use Fans to Help With Cross Ventilation
When you don't have a nice cool breeze handy, you can use a fan or two to get the air moving in the right direction.
It may surprise you to know that the most efficient way to ventilate a room is to face the fan out of a window rather than into the house. This method draws cooler air in at the inlet opening and creates a better vacuum to better pull warm, dusty air out.
NOTE: Many ceiling fans have a switch to reverse directions. Cooler air is pulled up from the lower portion of the room and thrown out at a higher point to fall back over the area. Use this feature to mix your air and have a more comfortable, even temperature throughout a given area.
Helpful Tips for Cross Ventilation
Why Is Cross Ventilation Important?
We may not want to admit that the air in our home is usually more polluted than the air outside. Cross ventilation pushes warm air out, and with it, dust and pollutants.
You can save money on utility bills with this method in the early morning and evening hours. The air is usually cooler during these times, so air conditioning units don't need to be run as often. If you're not sure what to do, try setting the thermostat to cool.
If your air conditioner kicks on when the windows are open, that means it's cooler inside and it's time to close up. If it doesn't start, that means you're saving money! The air conditioning won't come on unless it needs to, so don't worry about turning it off when the doors are open. This also helps when you run errands and don't want the heat to greet you when you return.
Being Efficiently Efficient
Keeping Indoor Air Fresh
Cross ventilation is a great way to quickly freshen up the air in your home. But when you need to close up the house, you should be able to keep your home's air fresh. Luckily, there are some things you can do to maintain that freshness on more of a long term basis.
These are the two most effective things you can do today to keep the air in your home clean and fresh after you're done cross ventilating.
- Replace Your Home's Air Filter. This will not only help to freshen up and clean the air cycling through your home's central air system, but it will also help to extend the life of your furnace. I prefer these Filtrete MPR 1000 filters. They'll filter out all but the worst dirt in the air, help to keep your air ducts clean, and won't clog too quickly.
- Clean Your Home's Air Ducts. No matter how well you cross-ventilate or how good of a filter you put in your home's air system, if you have dirty air ducts, you'll always be pumping dirty air through your home full of dust, dirt, and dander. I wrote an article all about how you can clean your home's air ducts yourself to help you out.
These simple things can make a big difference, not just for your health, but also for your general happiness. A fresh home is a happy home!
Welcome to the Clean Air and Lower Utility Bills Club!
I know the concept of cross ventilation seems simple, but I see homes closed up all day during the summer and want to tell people how beneficial a cross breeze can be when we catch a pleasant day.
Welcome to the fresh-air club! There's plenty to go around and best of all, it's free!
Other Helpful Ventilation and Cleaning Articles
- Furnace Smells: How to Reduce or Eliminate Odors in Your Air Ducts
Smells originating from our furnace and duct work are not only unpleasant but can present health concerns as well. Learn more about what causes them and how to get rid of these unwelcome odors.
- How to Heat and Cool Rooms With High Ceilings
Heating and cooling a room with vaulted or high ceilings as well as how to better cool and heat the second floor of our homes are very commonly asked questions about our HVAC system. Find out a few options and tips you may try to use to help you acco
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: How do you judge outdoor wind direction?
Answer: I usually rely on weather reports that generally relay from which direction the wind would come from on a given day.
Question: During winter, I have too much moisture inside my windows. What can I do to better cross ventilate?
Answer: If you have a humidifier, turn it down a little at a time till the moisture goes away. If not, I hate to say but you need new windows. It's because the heat inside and cold out is causing this and new windows are the only answer.
© 2012 Dan Reed
Mmargie1966 from Gainesville, GA on April 18, 2012:
I love being a member of the clean air and lower utilities bill club!
Thanks so much for all your tips. Your hubs have proven to be quite helpful.
Voted up and useful!
Simone Haruko Smith from San Francisco on April 09, 2012:
Well, thanks to my VERY leaky windows, I have GREAT cross-ventilation in my apartment! It's less than ideal in the winter, but at least I can feel good about internal air pollution ;)
Dan Reed (author) on April 06, 2012:
In the words of the late Bob Marley - "Stir It Up". Air begins to displace itself as soon as it stops moving. The ceiling fan is a great way to keep the room temperature even. Thanks for reading summerberrie!
summerberrie on April 05, 2012:
cre8tor, I am the worst when it comes to changing my air filters. I will do better-your hub has inspired me to think more responsibly. I never thought about the inside air being more polluted than the outside air! Also,I forgot about the reverse ceiling fan trick. Thanks for the information.