What is an ERV Air Exchanger System? (Energy Recovery Ventilation)

Indoor air quality and energy efficiency are increasingly important factors for homeowners. As building science and home improvement evolve, Energy Recovery Ventilators (ERVs) are emerging as an essential solution for modern homes. 

This advanced ventilation system introduces fresh outdoor air while expelling stale indoor air and recovering energy and moisture from the outgoing air.

We’ll explore what is an ERV, how it works, and the factors to consider when choosing one for your home.

Understanding ERVs: The Next Generation of Ventilation Systems & Their Benefits

ERVs are designed to improve indoor air quality by exchanging heat and moisture between the outgoing and incoming air streams. This innovative feature makes your home more energy-efficient and comfortable while enhancing air quality. 

Moreover, energy recovery ventilators can reduce the risk of respiratory infections by minimizing pollutants, such as carbon dioxide and volatile organic compounds (VOCs), in indoor air.

Why ERVs Are on the Rise

The growing popularity of ERVs stems from their energy-saving potential and the influence of codes and standards. ASHRAE Standard 62.1 ¹ sets ventilation requirements for indoor air quality, necessitating more outside air for conditioning as older buildings are renovated.

ASHRAE Standard 90.1 ² regulates building energy consumption, often requiring ERVs for systems with large outside air intake. A forthcoming addendum will further tighten these requirements based on regional climate zones.

The upcoming Standard 189.1 ³, focused on high-performance green buildings, will mandate ERVs for systems with even lower outside air intake. In addition, it is expected that both ASHRAE 90.1 and Standard 189.1 will continue to become more stringent, pushing for net-zero energy use in buildings.

ERVs provide a cost-effective solution to reduce energy consumption without sacrificing indoor environmental quality. They are ideal for various commercial building applications with high occupant density, such as offices, schools, fitness centers, churches, and auditoriums. 

The combination of energy conservation benefits and evolving code requirements has driven the increasing demand for ERVs in the HVAC industry.

Decoding ERV vs. HRV: Navigating the Key Differences

Though ERVs and Heat Recovery Ventilators (HRVs) share some commonalities, they cater to different needs and operate via distinct mechanisms. For example, HRVs primarily recover heat from outgoing air in colder climates, making them suitable for regions with lower temperatures. 

On the other hand, ERVs are designed to recover heat and moisture, making them perfect for hot and humid climates where reducing indoor humidity levels and preventing mold growth is critical.

Read more and compare the two in our ERV vs HRV ventilation system guide.

Types of ERV Systems: Finding the Right Solution for Your Application

home air ventilation system

Energy Recovery Ventilators (ERVs) come in various forms, each designed for specific applications and offers unique advantages. The four main types are:

  • Rotary heat exchangers (wheels).
  • Plate heat exchangers (fixed cores).
  • Heat-pipe heat exchangers (refrigerant).
  • Runaround coils (water).

These technologies have been used for over two decades, providing effective solutions for various needs.

Rotary heat exchangers, or wheels, rotate between the exhaust and outdoor air streams, transferring heat between them. Metal wheels only transfer sensible energy, while some plastic wheels can also handle moisture (latent energy) when treated with a desiccant.

These wheels are popular for their low initial cost, reasonable pressure drop, easy maintenance, and compact size.

Plate heat exchangers, or fixed cores, offer a no-moving-parts alternative, making them suitable for applications where wheels may be prohibited, like hospitals. These larger and more expensive exchangers can be made of metal, plastic, or paper, with different materials offering varying energy transfer capabilities.

Heat-pipe heat exchangers rely on copper tubes filled with refrigerant to transfer heat between the exhaust and outdoor air streams. However, they can only recover sensible energy, limiting their applications.

Runaround coils are preferred when exhaust and outdoor airflows are far apart. 

These systems use water coils in both air streams, connected by pipes filled with a water/glycol mixture. Like heat-pipe heat exchangers, they only transfer sensible energy.

What to Consider When Choosing an ERV

Maintenance

Proper maintenance is vital for optimal ERV performance and longevity. Regularly cleaning the filters and inspecting the system for damage or wear and tear are essential steps to keep your ERV running smoothly.

Noise

ERVs can produce noise, a potential concern for homeowners. Choosing an ERV with a low noise level and installing it in a location that minimizes disturbance is crucial for maintaining a quiet living environment.

ERV System Cost

ERVs may be more expensive than traditional ventilation systems, so factoring in the cost is essential. However, the energy savings and improved indoor air quality often make an ERV a worthwhile long-term investment.

Here is a study that showed the cost of a typical ERV system is usually recouped in after two years of use.

Professional Installation

Ensure your ERV is professionally installed to properly integrate it into your home’s ventilation system and guarantee optimal performance.

Other Ventilation Options

While ERVs effectively improve indoor air quality, it’s crucial to consider other ventilation options, such as natural and exhaust-only ventilation. Assess all options and choose the one best suited to your needs and goals.

The Multifaceted Impact of ERVs: Comfort and Efficiency Combined

ERVs serve several purposes, from supplying fresh, clean air and bolstering energy efficiency to ensuring a comfortable home environment. ERVs create a pleasant living space even in challenging climates by regulating temperature and humidity levels.

Mastering Humidity: Tailoring Your Air Exchanger to Your Needs

In hot, humid climates, excessive moisture in the air can cause discomfort and encourage mold growth. When choosing an ERV, it’s crucial to consider the size of your home, the number of occupants, and the local climate to ensure the system functions optimally. 

Installing a separate dehumidifier or opting for a ventilation system with a lower moisture transfer rate may be necessary to manage indoor humidity effectively.

Making an Informed Decision: Tips for Picking the Perfect Energy Recovery Ventilator

When selecting an ERV for your home, consider your home’s size, the local climate, and indoor air quality goals. While ERVs generally contribute to improved indoor air quality and reduced energy costs, finding the right system tailored to your specific needs is essential. 

Moreover, professional installation is crucial to ensure optimal performance and longevity.

A Guide to ERV Brands and Models

Several reputable manufacturers offer ERVs, each with its unique features and specifications. While the overall benefits of ERVs remain consistent, the specific performance, features, and pricing can vary among brands and models. 

Before choosing a specific brand or model, consult professional installers or HVAC experts to determine the best option for your home based on your needs, local climate, and budget.

Some popular ERV brands include:

  • Panasonic: Renowned for its energy-efficient and high-performance ERVs, Panasonic offers models such as the Intelli-Balance 100 with customizable airflow settings and an integrated MERV 8 filter for improved indoor air quality.
  • Broan: Broan’s line of ERVs includes the ERVS100S, a compact and energy-efficient model suitable for smaller homes. It features a HEPA filter and a moisture transfer rate of up to 65%.
  • Venmar: With a wide range of ERV models, Venmar caters to various home sizes and climates. Their HRV A160 model provides superior energy efficiency and an integrated heat recovery core to improve indoor air quality.

Potential Limitations of ERV Ventilation Systems

Despite the versatility of Energy Recovery Ventilators (ERVs) in managing indoor air quality and energy efficiency across a range of climates, their performance may be suboptimal in regions characterized by extreme temperatures or high humidity levels. 

Under these circumstances, homeowners might need to explore additional heating, cooling, or dehumidification solutions to ensure a comfortable living environment and maintain optimal indoor air quality.

So, Is an ERV the Solution for Your Home?

If you’re concerned about your home’s indoor air quality and energy efficiency, an ERV could be the ideal solution. However, it’s crucial to select an ERV customized to your needs and have it professionally installed for peak performance. 

When choosing an ERV, consider the local climate and indoor humidity levels to ensure the system effectively meets your air quality goals.

Proper home ventilation is vital for maintaining good indoor air quality and overall comfort. ERVs provide an innovative solution for homeowners looking to improve their living spaces while simultaneously reducing energy costs. 

These advanced ventilation systems recover energy and moisture from outgoing air, introducing fresh outdoor air into your home.

While ERVs and HRVs share similarities, they cater to different needs and operate in distinct ways. ERVs are particularly well-suited for homeowners in hot and humid climates seeking to reduce indoor humidity levels and prevent mold growth. 

By carefully considering factors such as your home’s size, indoor air quality goals, and the local climate, you can select an ERV that meets your specific needs and have it professionally installed for optimal performance.

References

1: Standards 62.1 & 62.2. (n.d.). Standards 62.1 & 62.2. https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2

2: Standard 90.1. (n.d.). Standard 90.1. https://www.ashrae.org/technical-resources/bookstore/standard-90-1

3: Standard 189.1. (n.d.). Standard 189.1. https://www.ashrae.org/technical-resources/bookstore/standard-189-1

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Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.