The Hows and Whys of A Well-Ventilated Home

A well-known building scientist named Joe Lstiburek of the Building Science Corporation says there are seven steps to a healthy home.

He identifies these areas as:

  1. dry
  2. clean
  3. well-ventilated
  4. combustion product free
  5. pest free
  6. toxic chemical free
  7. comfortable.

Today I’m going to talk about the third step: a well-ventilated home

The information I am providing is basic. If you have specific questions, please feel free to email me.


Why Ventilation is Important

Most of us spend 90% of our time indoors, much of it where we live. So our health is hugely influenced by the air we breath in our homes. Good home ventilation can help ensure the health of your home and family. Here’s how:

1) Proper Ventilation Reduces Condensation

This helps prevent mold and mildew from forming in the home, and keeps the humidity down, which is both more comfortable and more healthy.

2) Decreases VOC Concentrations & Radon Gas Levels

High concentrations of VOCs (which come from household chemicals and furnishings) and Radon (gas which is a naturally occurring carcinogen) can occur in a home that is not properly ventilated. Both of these are very detrimental to your health at high levels. Northern Virginia has many areas where Radon levels are high, and home ventilation in these areas needs to be adequate to ensure these levels are kept in the healthy range.

3) Proper Ventilation Reduces Airborne Allergens

Improperly ventilated spaces tend to trap airborne allergens such as pollen, dust, and other irritants, where they become concentrated. Proper ventilation can effectively help to reduce allergens by diluting the concentrated air and removing large allergen particles. This helps make your indoor air much more comfortable for allergy sufferers.

4) Creates Positive Pressure.

If the air pressure inside of your home is lower than the pressure outside of the home, outside are will be pulled inside. This is called negative pressure, and it allows unhealthy airborne contaminants to be sucked into your home. A positive pressure situation, which can be created using proper ventilation, ensures that air from inside the house is pulled outside, further helping with dilution of your indoor air and preventing dangerous buildups of combustable gases and carbon monoxide, among other airborne contaminants.

Well Ventilated

So how do you ensure that your home is properly ventilated?

The solution to indoor pollution is removal or dilution. The biggest sources of moisture and odors in the modern home are kitchens and bathrooms. Kitchen and bath exhaust fans provide active means of removing moisture and other elements. Be sure that your kitchen and bath fans vent outdoors, rather than just recycling the air through a filter. It is also extremely important that your clothes dryer vents outdoors. Exhaust fans and ducts should be cleaned on a regular basis to remove buildups of grease, oil, lint and dirt that can attract airborne pollutants.

Whole house mechanical ventilation, which can take many forms, can be:

  • supply only:  meaning that fresh air is brought into the home but not expelled
  • exhaust only: meaning that air is expelled from the home but fresh air is not brought in
  • balanced: meaning that fresh air is brought in and old air is expelled.

Obviously, a balanced ventilation system is the best way to ensure healthy air quality in your home. It is also the most expensive both in terms of the equipment and energy loss to your home through expelling conditioned air.

The good news is that there are a lot of tax incentives for buying and installing energy efficient tech in your home, which can help reduce the cost of investing in a balanced ventilation system. The Department of Energy keeps a searchable database:


 Energy Recovery

You can also install a system to help capture and retain the air temperature and humidity of your home’s air before it is expelled. Theses systems, called Energy Recovery Ventilators, help keep the warm air inside during the winter, and the cool dry air inside during the summer, and will significantly reduce home energy costs.


Other thoughts:

Humidity – during winter months keep relative humidity of the home to less than 30%.

Blinds and shades – use them to control solar gain or rejection depending on the season and location of the window.

Old, leaky exterior doors and windows? Consider replacing them with high-performance double glazed units. FYI, air-seal the gaps between the window and frame with low-expansion foam.

Green is a big passion of mine, and I love sharing my knowledge and experience with others. If you ever have any questions about how to make your home a more healthy living environment, more energy efficient, or anything else related to building and Real Estate, get in touch!

– Lou


Contact Lou Sagatov