What Is an ERV and How Does It Work?

Does your home feel stuffy and polluted, or maybe you’re constantly battling with high energy bills? If these problems sound familiar, an Energy Recovery Ventilator (ERV) might be the solution you’ve been looking for.

What Is an ERV?

An ERV is a mechanical ventilation system connected directly to your HVAC system. It helps improve the air quality in your home by exchanging stale indoor air with fresh outdoor air.

But it doesn’t just swap air. Unlike a Heat Recovery Ventilator (HRV) which only recovers heat, an ERV exchanges both heat and moisture between the incoming and outgoing air streams to keep your home comfortable while saving energy.

How Does an ERV Work?

On mild days, particularly in the spring and fall, you may enjoy cracking open the windows to let in some fresh air. Unfortunately, that’s not always possible or efficient when the temperature spikes in the summer or plummets during the winter. An ERV solves this problem by using a heat exchanger. Here’s how it works:

• Air Exchange: An ERV uses two fans and two air streams. One fan pulls in fresh outdoor air, while the other expels stale indoor air simultaneously. The air streams never mix, but they pass through a crossflow energy transfer core where heat and moisture transfer occurs.
• Heat Transfer: During this process the ERV uses a heat exchanger to recover heat. During the winter, the outgoing warm, stale air preheats the incoming cold, fresh air. Meanwhile, in the summer, the outgoing cool, stale air helps to cool the incoming hot, fresh air before bringing it to your HVAC unit.
• Moisture Control: ERVs do more than just refresh your indoor air; they also boost comfort by helping manage humidity levels. In the winter, they capture warmth and moisture from the stale air being exhausted and transfer it to the incoming fresh air, so your home feels comfortable without having to crank up the thermostat. In the summer, they work in reverse by removing excess heat and moisture from the air coming in, so your living space feels cooler and less sticky, even if you don’t lower the temperature.

With balanced ventilation, an ERV system ensures there’s an equal amount of fresh air coming inside with the same amount of stale air being exhausted outdoors.

Why Consider Adding an ERV?

Improved Air Quality

ERVs bring in fresh outdoor air, which can help reduce indoor pollutants, allergens, and odors. This is especially beneficial if you live in an area with poor air quality or if someone in your home has respiratory issues. An ERV can also help prevent mold growth, odors, condensation on the inside of windows, and respiratory symptoms.

Energy Efficiency

By transferring heat and moisture, ERVs help maintain a consistent indoor temperature and humidity level. This means your heating and cooling system doesn’t have to work as hard, leading to potential energy savings while extending your system’s lifespan. The U.S. Department of Energy (DOE) estimates that ERVs can recover about 70-80% of the heat energy in the indoor air and transfer it to the incoming fresh air.

Comfort

Maintaining proper humidity levels can make your home more comfortable. In the winter, an ERV prevents the air from becoming too dry, which can lead to dry skin, infections, respiratory issues, and damage to wood flooring and furniture. In the summer, energy recovery ventilation systems can help reduce excess humidity to prevent respiratory problems and mold growth.

How Much Does an ERV Cost?

The cost of an ERV can vary depending on your home’s size and the model you choose. On average, expect to pay between $1,000 and $3,000 for the unit itself.

Installation costs can add another $500 to $1,500, depending on how difficult the job is and your location. While this might seem like a significant investment, the potential energy savings and improved air quality can make it worthwhile in the long run.

Potential Drawbacks of Installing an ERV

While ERVs offer many benefits, there are a few potential drawbacks to consider:

1. Initial Cost: The upfront cost of buying and installing an ERV can be high. However, the long-term energy savings and health benefits can offset this initial investment.
2. Maintenance: ERVs require regular maintenance to ensure they operate efficiently. This includes cleaning or replacing filters and checking the heat exchanger for any buildup.
3. Climate Considerations: In extremely hot or cold climates, an ERV might not be as effective as other ventilation options.

Should You Install an ERV?

It depends. While newer homes are designed to be air tight to keep conditioned air from escaping, this can also cause the air to become stale and odors to linger. In these cases, an ERV might be a good choice. But if you live in a relatively mild climate and can open windows throughout the year, installing an ERV may not be necessary.

Consult with a professional to determine if an ERV is the right choice for your specific situation and home.