Why You Need to Ventilate Your Home

Ventilation is very important in an energy-efficient home and it helps control moisture allowing homes to breathe. If it’s lacking ventilation it can lead to mold growth and eventually lead to structural damage. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is the determining body on how much a home’s living area should be ventilated.

Here is the formula, if you are interested: CFM = 0.03A + 7.5 (# bedrooms + 1)] as published by ASHRAE 62.2 in 2013

There are three basic ventilation strategies:

  • Natural ventilation
  • Spot ventilation
  • Whole house ventilation

Each of these strategies poses different solutions and steps to ensure the most efficient and effective ventilation. Having a fundamental understanding of each one will help you determine how to ventilate your home.


Natural Ventilation

natural-home-ventilationThis is an unpredictable and uncontrollable form of air movement. The air infiltrates the house through cracks and small holes, typically found in older homes.

With today’s building techniques, we are sealing those cracks and holes to make our homes more energy-efficient, but ventilation is necessary to maintain a healthy and comfortable indoor environment. Opening windows and doors would provide natural ventilation, but many people keep their homes closed up because they use central heating and cooling systems year-round.



Spot Ventilation

Spot ventilation can improve the effectiveness of natural and whole-house ventilation by removing indoor air pollution and/or moisture at its source. Spot ventilation includes the use of exhaust fans, such as those used above kitchen ranges and in bathrooms.

However, by using kitchen hoods and bath fans as a form of ventilation in an air tight home we are causing the home to be put in a negative pressure or “vacuum”. The effect of this happens when you open up a door leading to the outside and you feel a large gust of wind coming into the house, just to find out, as soon as you step outside the weather is calm. Now think about all the allergens coming in with that air. Is that what you want inside your home?


Whole House Ventilation

This is universally known as the most efficient and effective form of ventilation. Whole-house ventilation systems provide controlled, uniform ventilation throughout a house. They use one or more fans and duct systems to exhaust stale air and/or supply fresh air to the house, allowing for a more controlled form of air-flow.

There are two types of whole house ventilation systems to consider:

Supply ventilation systems work by pressurizing the building. Referring back to spot ventilation, rather than sucking in the air when you open the door, you would be pushing the air out. Similar to when you walk into a hospital or any other healthcare facility.

Balanced ventilation systems ( HRV, ERV ), if properly designed and installed, neither pressurize nor depressurize a house. Rather, they introduce and exhaust approximately equal quantities of fresh outside air and polluted inside air.


Heat Recovery Ventilators (HRV) provide controlled ventilation while minimizing energy loss. They reduce the costs of heating ventilated air in the winter by transferring heat from the warm inside air being exhausted to the fresh (but cold) supply air. In the summer, the inside air cools the warmer supply air to reduce ventilation cooling costs.

To prevent any damage or uncomfortable stuffiness to your home, a ventilation system is crucial for its foundation. It’s easy to dismiss this type of airflow as a priority–afterall, you can’t even see it. But it’s proven to be an important component for your house both now and later. So reconsider your current ventilation in your house. Is it good enough? Or is it time for a ventilation makeover?

Author: Joe Tollari