You may not give much thought to the ventilation of your home. Perhaps you are always just concerned with whether or not it's properly heated and cooled. However, if your home doesn't have good ventilation, it could trap hot air and humidity, and this can lead to mould and mildew growth and damage to the home's frame and building materials. While there may not be one simple test you can conduct to note if your home needs more ventilation, usually it's easy enough to determine if you take a few things in consideration.
1. Your home is always warm and stuffy
During the summer, if your home seems warm and stuffy even when the air conditioner is running, it may not be that you need a new A/C unit but that the home needs some ventilation, especially in the roof. Remember that heat rises and if your home has no ventilation, that heat can get trapped in the attic or upper floors and then your entire home feels stuffy.
Note, too, that your home needs ventilation in order to move cool air from your air conditioner around; otherwise, it's simply blown out of the vents and then sits in any one room, not really cooling the entire space. If you know your air conditioner is properly sized and there are no other issues with why it should be so warm in your home, consider adding some roof ventilation.
2. Upper floors have mould growth
If your home has mould growth in the bathroom, you may need more ventilation in that room alone. A stronger bathroom fan or opening a window during or right after a shower can be enough to compensate. It's also not unusual for a basement to be very damp, as it allows in moisture from a poor-quality foundation. However, when you have mould in the upper stories of the home, this usually means that there isn't enough ventilation throughout the entire house. Without enough air circulation, that added moisture from cooking, bathing, and just the atmosphere gets trapped before it evaporates and causes mould growth.
3. Someone in your family gets a breathing disorder
If anyone in your family has trouble breathing, of course you want this diagnosed by a healthcare professional. However, they may be struggling against the mould, mildew, dust mites, pet hair and dander, and other contaminants trapped in the air that are not being circulated to the outside of the home. Installing roof ventilation can mean pulling out those trapped contaminants and also bringing in fresh air, allowing everyone to breathe more comfortably.