Your Health and Mechanical Ventilation: Why You Need It In Your Home

If you've been following along with me for a while, you know how I feel about including mechanical ventilation into your home.  Mechanical ventilation is a MUST in every home, old or new.

And now we have results from an amazing study that shows WHY mechanical ventilation is so important for our health and longevity.

I'll dive into what I mean by mechanical ventilation and the aforementioned study in this article.

Mechanical Ventilation: What is it?

Good question!  In broad terms mechanical ventilation is anything that is venting (removing air) from your house that is run by electricity - something that has a motor.   It's not referring to natural ventilation which would include opening doors and windows, or having louvers that open and shut manually.

Mechanical ventilation exists because the air in our homes is not clean.  Everything in a home has the potential to create toxins from the finish materials to the furniture to the cleaning and body care products we use, and even from cooking (ESPECIALLY from cooking).  

And many homes are so air tight that we aren't getting enough oxygen from outside air.  This leaves us breathing in a lot of carbon dioxide.  

Mechanical ventilation is also necessary to control moisture and prevent mold.

Are there different types of mechanical ventilation?

Yes!  And they aren't all created equal.

The most basic form of mechanical ventilation is probably in your home already.  These are exhaust-only systems.  You most likely have an exhaust fan in your bathroom and at your kitchen stove.  These are code minimum requirements.  But they aren't good enough.  They aren't taking care of most of the poor air quality in your home.

To start with, they usually don't get turned on.  These systems require you, the occupant, to remember to turn the fans on.  Plus, often they're noisy so people don't want to turn them on.

And even if they are used properly whenever someone is cooking or taking a shower, they aren't on all the time.  And they are in such specific areas of the house that they are only targeting a small portion of the air in the home. 

And finally, an exhaust only system isn't bringing fresh air into your home.  You need fresh air for cognitive function.  And you need fresh air to balance out the stale air that's being exhausted.

Side note: There are 'whole house' exhaust-only ventilation systems that can be installed to help exhaust all the rooms in the house and that run continuously, but unfortunately these still are not good enough (though they are better than the bathroom/kitchen code-minimum scenario).  

And they can actually do harm.  The pressure within a house always needs to balanced.  So if you have an exhaust fan running constantly in your house, outside air is being sucked into your house to equalize the pressure of the air that's leaving the house.  This usually happens through cracks and gaps in the walls, roof and foundation.  And it can be dangerous because you're bringing in toxic, unfiltered underground or outdoor air that might be passing through wall cavities with mold or rodent carcasses. (Ick.)

What do you need in your home?

A balanced mechanical ventilation system with a heat recovery unit known as Heat Recovery Ventilators (HRV) or Energy Recovery Ventilators (ERV).  The type (ERV vs HRV) that is installed in your home depends on your climate and location. 

An HRV/ERV is a box that sits in a utility room or installed at the ceiling that brings fresh air into your home at the same rate that it exhausts stale air.  It's connected to air ducts that run through your home (especially bedrooms) to bring fresh, filtered air into the house. 

The stale indoor air is then exhausted through the same box, but in a different chamber so the air doesn't mix, and then thrown back outside.  These units run continuously.

The reason the exhaust air goes into the same box as the fresh air is so that the heat can be 'recovered' from the indoor air to help warm up the outdoor air before entering your home (or vice versa in summer).

The image below shows the 'box' and fresh air vs stale air chambers.

Why do you need balanced Mechanical ventilation?

This is where the new study from Enterprise Community Partners comes in.

Enterprise is a nonprofit 'that exists to make a good home possible for the millions of families without one.'  They have a very successful healthy and sustainable housing certification program called Enterprise Green Communities.

The study shows that continuous mechanical ventilation significantly reduces exposure to contaminates that poorly effect health.

Most notably is the difference it makes for PM 2.5 exposure.  PM (Particulate Matter) 2.5 is linked to respiratory issues.  It affects everyone, but like all things it can affect kiddos the most, and this can be seen in the amazing amount of child asthma cases throughout the country.

Read the article about the study here (It's a short article, and definitely worth the read!)

How Continuous Mechanical Ventilation improves health

This chart from the study shows how a continuous mechanical ventilation system in your home can improve your health outcomes.

Does this mean I don't have to worry about my gas stove?

Sadly no.

The study also found that mechanical ventilation did not address the nitrogen dioxide in the house, which comes from fuel burning appliances like gas cooktops and ovens.  And this has a major impact on respiratory health.

Here's a study by the Rocky Mountain Institute on cooking with gas.

Final Thoughts

Getting fresh air into your home is one of the best things you can do for your family's health.  And the best way to do that is to install a balanced mechanical ventilation system in your home.

But if you can't install an HRV/ERV just yet, here are some other things you can do:

• Install a ductless HRV by Lunos.  They are less expensive and easier to install.  And if you're renting, you might have an easier time convincing your landlord to install these rather than a whole house ventilation system.
• Use your kitchen and bath fans whenever you're cooking or bathing.  Turn on the fans prior to cooking and prior to turning on the shower.
• If you have a recirculating range hood, replace it with a hood that vents outside if possible.  The recirculating hoods could be doing more harm than good.
• If you have a gas stove and can't replace it with an electric stove you can look at portable cooktop and oven options.  I'm in a rental house and don't have the option to replace appliances. So I purchased a portable oven (it's a combination steam / convection oven) that sits on the counter.  I also purchased a single burner induction cooktop that sits on the counter.