Modern homes are airtight and therefore need mechanical ventilation. ERV and HRV are methods of mechanical ventilation used to improve indoor air quality. They work in similar ways, but there is a little bit of difference. This post focuses on the difference between ERV and HRV.
What Is Home Ventilation?
There are three methods for home ventilation: natural ventilation, spot ventilation, and mechanical ventilation.
Natural ventilation is the most common method of home ventilation. It means relying on airflow through open doors and windows. And this airflow is inconsistent.
Spot ventilation improves air quality in a particular room, such as the kitchen.
Mechanical ventilation is the most reliable method of ventilation. The method is also known as whole-home ventilation. The procedure involves consistently capturing fresh air from the outside and circulating the air inside the home.
Let’s go a little bit deeper into mechanical ventilation. It offers three options: supply-only, exhaust-only, and balanced. Of the three options, a balanced ventilation system is preferable because it combines the features of supply-only and exhaust-only systems. It does two things simultaneously: removing stagnant air and bringing in the fresh air.
Both ERVs and HRVs fall into the category of balanced home ventilation systems. Now we will see how these systems work.
How Does an ERV System Work?
ERV stands for “energy recovery ventilation.” An ERV system has two fans. One fan pushes stale air out of your home, and the other draws in fresh air.
Within the system is a heat exchanger that transfers heat energy from the outgoing airstream to the incoming airstream. As a result, the system replaces stale air with fresh air, but the temperature remains the same.
How Does an HRV System Work?
HRV stands for “heat recovery ventilation.” HRV systems are highly energy-efficient. They vent stale air outdoors and replace the stale air with fresh air captured from outside.
Two separate airstreams pass through the system. As they cross paths, the stale air transfers heat to the fresh air. As a result, there is no energy wastage, and the temperature in your room remains constant.
In summer, to cool the incoming air, the opposite effect occurs.
What Is the Difference between ERV and HRV?
Depending on the season, HRV systems only recover cooled or heated air. On the other hand, ERV systems go a step further and recover heat and humidity.
An HRV ventilator core works more or less the same way as the human breathing system. The exchange of air occurs inside the unit. But as the heat recovery process takes place, incoming fresh air and outgoing stale air do not mix. These airstreams pass in separate channels.
To understand the main difference between ERV and HRV units, you have to be familiar with another concept: efficiency rate. Every HRV device has a specific efficiency rate. This rate determines how much energy the particular device can save. Although a fan moves in the device continually, the device saves more energy than the fan requires.
We encourage you to invest in a high-quality HRV system because the fan wears out quickly. HRV systems produced by the established brands come with durable, silent, and energy-efficient fans. Typically, the efficiency rate is between 55% and 75%. However, some models offer higher efficiency.
In terms of operation, there is not any significant difference between ERV and HRV systems. ERV systems capture both heat and humidity. Before introducing fresh air from the outside, it removes humidity from the air. Thus, dehumidifiers and air conditioning systems work less, which saves energy. During the winter, the unit produces the exact opposite results. The unit extracts humidity from the outgoing air and transfers the moisture to the incoming dry air.
Factors to Consider When Choosing an ERV or HRV system
Above, we discussed the difference between ERV and HRV systems. Below are factors to consider when determining the type of ventilation right for you:
First, consider where you live. You should choose an ERV system if you have long, dry winters and hot, humid summers. This system will maintain comfortable humidity inside your home.
Installing an ERV can also lead to lower energy consumption because, in such a case, the air conditioner will not have to work that much. To reduce humidity in the home, we recommend using a dehumidifier, even using a ventilation system.
The humidity levels, to a great extent, depend on the number of family members. More cooking, breathing, and showering mean a higher level of humidity. If many people live in a relatively small home, there is usually more moisture in the air. For a large family, an HRV is a better choice than an ERV.
Your personal needs
When choosing a ventilator, the needs of you and your family also have to be taken into consideration. Does a member of your family suffer from asthma or allergies? Before choosing a particular ventilation system, learn if dry air causes discomfort for anyone in the family. In such a case, an ERV unit can be a better option than an HRV unit.
Difference Between ERV and HRV – Final Thoughts
The main difference between ERV and HRV systems is that an ERV system transfers both heat and moisture, but an HRV system transfers only heat. You may choose an ERV or HRV system depending on the climate of the region you live in and your personal preference.