What is an Energy Recovery Ventilator?

Energy Recovery Ventilators

Homes and buildings are being constructed or renovated to be tighter than ever before to save energy. Sealing gaps and cracks in the building envelope stops the exchange of air with the outside, conserving energy and promoting comfort. In tight homes without adequate ventilation, however, airborne contaminants get trapped indoors, compromising your family’s health.

High indoor air quality requires a pathway for excess moisture and contaminants to leave the home and for fresh air to enter. Zehnder heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs) provide clean air solutions for homes, commercial spaces, medical buildings, and schools.

Promote Fresh Air for a Healthy Home

Many homes and businesses have poor indoor air quality due to pet dander, mold, dust, volatile organic compounds (VOCs), and excess carbon dioxide. Indoor air pollution can cause fatigue, respiratory issues, headaches, dizziness, and difficulty concentrating. Indoor air pollution is a top environmental health risk, according to the EPA.

Conversely, clean home air is associated with restful sleep, fewer allergy or asthma symptoms, better concentration, and a strong immune system. It is essential to have a proper ventilation strategy to ensure stale, contaminated air is replaced by fresh air.

Zehnder energy recovery ventilation systems extract stale air from the kitchen, bathrooms, laundry room, and mechanical room and supply fresh, filtered air to the bedrooms and living spaces. Numerous projects with Zehnder ComfoAir systems have shown a significant reduction in the levels of carbon dioxide, VOCs, particles, microbes, humidity, and odors.

Choose the Right System for Your Home or Business

What Is the Difference between an HRV and ERV? Although both systems supply fresh air while extracting stale air, there is one key difference: energy recovery ventilators also allow moisture to pass from the airstream to the other. That is, while heat recovery ventilators transfer heat or coolness to the incoming air, energy recovery ventilators transfer heat or coolness, and moisture.

Should I Install an HRV or an ERV? This depends on your climate and how the home or business is occupied. ERVs are commonly installed in climates with dry winters and/or humid summers. During the winter, an ERV helps keep humidity levels in an ideal range by capturing moisture from the exhaust air and transferring it to the intake air. In the summer, moisture from the intake air is transferred to the exhaust air, lowering moisture levels. In contrast, if your home has elevated humidity in the winter and/or low summer humidity, then an HRV is a better fit. Dense occupation (many inhabitants) and lots of pets or large aquariums will introduce more humidity into a home, thus an HRV may be better in some cases.

Modify Humidity Levels for Greater Comfort

The relative humidity level of your home has a big impact on your comfort. In the winter, dry indoor air can cause dry skin and an itchy throat. In the summer, it feels warmer when the humidity is high. As a result, removing excess humidity in the summer offers relief and in some cases can reduce the need for air conditioning. An ERV requires dramatically less energy than an air conditioner because it contains only a fan and doesn’t have a condenser.

Prevent Moisture Issues for Cleaner Home Air

High home humidity levels can cause condensation issues, promote mold growth, and boost dust mite populations. These biological contaminants can degrade indoor air quality and trigger asthma or allergy symptoms.

First, it is essential to fix leaks in the plumbing system or building envelope to prevent standing water. Next, clean up any concerning mold growth. Finally, address excess indoor humidity that results from bathing, cooking, washing dishes, and drying clothes. Humidity issues are especially common in bathrooms, kitchens, and utility closets and can be mitigated with an effective ventilation strategy that removes moisture.

Many homes rely on exhaust fans to vent moisture, odors, and stale air. Unfortunately, exhaust fans are often inadequate in removing contaminated air, especially in tightly constructed homes. Exhaust fans work only if enough makeup air can enter the home through gaps and cracks to replace the air vented out.

Zehnder energy recovery ventilators are balanced ventilation systems that supply and exhaust equal quantities of air.  The two air streams do not mix, preventing cross-contamination.

Remove Contaminants with Air Filters

In most homes, the majority of the outside air enters through gaps and cracks in the building envelope. Unfortunately, this air is often drawn in through the basement, crawl space, attached garage, or attic, which are commonly the most contaminated locations in the home. This gives dust, pollen, mold spores, and vehicle exhaust a pathway into the living spaces.

By contrast, ERV and HRV systems are designed with air quality in mind. The intake air on Zehnder ERVs is strategically located on the outside of the house with fresh air in mind, and all incoming air is filtered before being dispersed in the home.

This process removes many common contaminants, including pollen, mold spores, bacteria, and smog, for cleaner indoor air. Using a filter with a high Minimum Efficiency Reporting Value (MERV) rating ensures that smaller particles are removed; Zehnder has filters up to a MERV 13 rating.

Use Zehnder Technical Expertise

Zehnder provides complimentary technical assistance and expertise every step of the way. The system design service helps clients determine the right system for their home or business, as well as the layout of the ventilation tubing and equipment. Technical support is available during the system installation, and Zehnder air quality experts provide a commissioning service. These services help extend the life of the ventilation equipment, reduce energy costs, and ensure proper airflow rates for cleaner indoor air.

Save Energy for a Comfortable Green Home

Many home ventilation systems increase heating and cooling costs while causing drafts in the home, degrading indoor comfort. Just like ventilating a home by leaving a window open, many ventilation systems exhaust conditioned air without recycling the heat. Exhaust fans need makeup air to operate properly, drawing in unconditioned air through gaps and cracks in the building exterior. This has a huge impact on energy bills and comfort.

Zehnder ERV systems conserve energy and are commonly used in high-performance construction and retrofit projects. The heat from the exhaust air stream is transferred to the intake air during the colder months, saving energy. Zehnder energy recovery ventilators are the most energy-efficient units on the market and are widely used in projects meeting LEED, Passive House, and ASHRAE 62.2 standards.