Optimizing Fresh Air in Your Home: The Essentials of HRV and ERV Systems

By, Kate Hamblet

These systems continuously bring in fresh air while exhausting stale air, creating a comfortable and healthy home environment. However, not all installers are well-versed in the proper setup of HRV and ERV systems. As a homeowner, understanding the basics will help you ensure your system is installed correctly, whether you're incorporating one into a new build or retrofitting it into an existing home.

Optimizing Fresh Air in Your Home

The Essentials of HRV and ERV Systems

When building or renovating a home, ensuring proper ventilation is critical for maintaining healthy indoor air quality. Modern airtight homes are excellent for energy efficiency, but without intentional ventilation, they can trap pollutants, moisture, and stale air inside. That’s why a balanced mechanical ventilation system—such as a Heat Recovery Ventilator (HRV) or an Energy Recovery Ventilator (ERV)—is essential.

How HRVs and ERVs Work

HRVs and ERVs work by exchanging stale indoor air with fresh outdoor air while recovering heat (and in the case of ERVs, also moisture) from the outgoing air to improve efficiency. This means your home receives a steady flow of fresh air without losing excessive heat in winter or gaining too much heat in summer.

Most climates in the US are going toward ERVs now rather than HRVs, but it’s always best to consult with an expert in your area to decide if an ERV or HRV is right for your home.

Proper Placement of Fresh Air and Exhaust Ducts

To optimize fresh air circulation throughout your home, the placement of supply and exhaust vents is crucial.

Fresh air supply vents should be located in:

1. Bedrooms

2. Living rooms

3. Home offices

Exhaust vents should be installed in:

1. Bathrooms

2. Kitchens

3. Laundry rooms

This strategic placement creates a cascading ventilation effect—the fresh air introduced into bedrooms and living areas naturally flows toward the exhaust vents in moisture- and pollutant-prone spaces. This movement ensures the entire home benefits from continuous air exchange, preventing stagnation and improving overall indoor air quality.

Considerations for Installing an ERV System

Here are some best practices and things to consider before installing an ERV in your new home build or renovation.

Ductwork

ERV ductwork is different from heating/ cooling ductwork, so you will need to install new ductwork into the home if renovating or ensure separate ductwork is installed if building a new home. Sometimes ERVs can be ducted into existing ductwork, but it’s not good practice. For the best results and the best air quality, ensure that your ERV system has its ductwork.

Location

Every part of an ERV system needs to be inside the building envelope, which means inside the insulated part of the house. If your attic or crawl space isn’t insulated, you can’t put the ERV unit or ductwork in there.

Space

The main unit of the ERV doesn’t take up a lot of space. They can be hung off a wall or ceiling (depending on the brand).

• If you’re building a new home, make sure you have space in your mechanical room for the ERV unit.

• If you’re renovating and don’t have space in a mechanical room, see if you have space in a laundry room or other storage area. If your basement is insulated, then that’s also a good place for the ERV unit.

• The ductwork that goes to each room is small and can fit within a 2x6 wall cavity. But you will need to plan for the supply and exhaust ductwork that goes between the interior and exterior of the house. Sometimes a service chase (imagine a really small elevator shaft) is needed for those larger ducts.

Electrical Needs

Ensure there's an available power source where the ERV will be installed. Generally, ERVs don’t require special power considerations.

Exhaust Venting

The intake grille on the outside of the house needs to be roughly 10’ away from the exhaust grille so that the ERV intake isn’t sucking up all the gross air it’s exhausting from your home. ERV manufacturers will have their own guidelines for distances and locations, so follow their recommendations.

Balancing the Ventilation

The HVAC contractor is responsible for balancing the ventilation unit after installation by adjusting airflow rates to ensure the right amount of fresh air is supplied to living spaces and stale air is properly exhausted. This process includes measuring and fine-tuning airflows, checking duct pressures, and verifying that the system operates efficiently to maintain healthy indoor air quality and energy efficiency.

Ensuring Proper Installation

Not all HVAC professionals or builders are knowledgeable about balanced ventilation systems.

If an installer doesn’t follow the best practices and manufacturer guidelines for installation, your home’s air quality and efficiency could suffer.

As a homeowner, you can ask the right questions to make sure you’re in good hands. Use the best practices outlined in this article to gauge whether an installer is experienced with HRV/ERV systems.

A Healthier Home With Fresh Air Ventilation

Balanced ventilation with an HRV or ERV is the best way to maintain healthy, fresh indoor air in an airtight home. Whether you're building a new or upgrading an existing home, understanding how these systems work will help you make informed decisions—and ensure that your installer does the job right.

By prioritizing fresh air where it matters most and ensuring proper airflow throughout your home, you’ll create a comfortable, efficient, and healthy living environment for you and your family.

By, Kate Hamblet

The Wellness Architect

Balanced Architecture

Kate helps health-conscious families create homes that support and promote health, happiness, and longevity. You'll find her at www.balancedarchitecture.com