Ductless HRV and ERVs - Breathe New Air into Your Home
Last Updated: Oct 4, 2024We all need fresh air. But energy-efficient homes are built to be airtight. So - how can you get the fresh air you need while keeping your energy bills low? A heat recovery ventilator or an energy recovery ventilator (HRV/ERV) is critical. These have become vital components for efficient homes. Suppose you are renovating an older home, making it more efficient and airtight. In that case, you should consider the addition of an HRV or ERV.
Table of Contents
- What Is A Ductless HRV or ERV?
- What Are Use Cases for Ductless Energy Recovery and Heat Recovery Ventilators?
- What Are The Differences Between An ERV and HRV?
- Do Ductless ERVs and HRVs Improve Indoor Air Quality?
- Can I Run an ERV or HRV Year-Round?
- Will an ERV or HRV Help Reduce Odors in My Home?
- How Often Do I Need to Change the Filters in an ERV or HRV?
- Are ERVs and HRVs Noisy?
- Can an ERV or HRV Reduce Condensation and Mold Growth?
- Is Professional Installation Required for Ductless ERVs or HRVs?
- How Do ERVs and HRVs Affect My Energy Bills?
- How Do I Choose Between an ERV and HRV for My Home?
- How Much Do Ductless HRVs and ERVs Cost?
- Who Makes Ductless HRVs and ERVs?
Most HRV and ERV systems use ducts to bring the exhaust air to the central heat-exchange unit and send the fresh air back through the building. They also have separate vents to bring in fresh outside air and send out stale exhaust air. That's a lot of ducts!
What if you don't have room for all those ducts or don't want them? There is a solution – the ductless heat recovery ventilator.
What Is A Ductless HRV or ERV?
A ductless HRV (Heat Recovery Ventilator) or ERV (Energy Recovery Ventilator) is a ventilation system that provides fresh air to your home without the need for an extensive ductwork system. These units work by exchanging stale indoor air with fresh outdoor air while recovering heat (in the case of HRVs) or both heat and moisture (in the case of ERVs) from the outgoing air. This process helps maintain indoor air quality and energy efficiency in homes, particularly in spaces where installing traditional ductwork is impractical.
What Are Use Cases for Ductless Energy Recovery and Heat Recovery Ventilators?
Ductless Energy Recovery Ventilators (ERVs) and Heat Recovery Ventilators (HRVs) are versatile solutions that provide efficient ventilation while maintaining energy efficiency. Below are some specific use cases where these systems shine:
1. Urban Living
In densely populated urban areas, space can be limited, and installing traditional ductwork is often impractical or impossible. Ductless ERVs and HRVs are ideal for apartments, condos, and high-rise buildings where adding full HVAC ducting isn’t an option. These systems require minimal space and allow urban dwellers to maintain indoor air quality without sacrificing energy efficiency.
2. Retrofitting Older Homes
Older homes often lack proper ventilation, especially those built before modern energy codes were established. Retrofitting these homes with a ductless ERV or HRV system offers an efficient way to introduce controlled, balanced ventilation without the hassle and cost of extensive renovations. These units can be easily installed in existing walls or ceilings, providing an energy-efficient way to improve indoor air quality while reducing moisture and humidity issues commonly found in older homes.
3. Small Commercial Spaces
Ductless ERVs and HRVs are not just for residential use; they are also highly beneficial in small commercial environments like offices, shops, and classrooms. In spaces where air quality is essential for comfort and productivity, these systems help maintain a constant flow of fresh air while minimizing energy consumption. Schools, in particular, benefit from the balanced ventilation provided by these systems, which can help create a healthier learning environment by reducing airborne contaminants.
4. Passive and Net-Zero Homes
For homeowners looking to build or retrofit their homes to meet passive house or net-zero standards, ductless ERVs and HRVs are key components in achieving optimal energy performance. These systems are designed to recover heat or energy from the air being ventilated out, making them essential in homes that prioritize energy conservation and sustainability.
By providing flexible, energy-efficient solutions for ventilation, ductless ERVs and HRVs serve a wide range of needs across different living environments, from modern urban apartments to energy-conscious passive homes.
What Are The Differences Between An ERV and HRV?
While both Energy Recovery Ventilators (ERVs) and Heat Recovery Ventilators (HRVs) provide balanced ventilation by exchanging indoor air with fresh outdoor air, they have distinct functionalities that make each suitable for different climates and specific needs. Below is a breakdown of the key differences to help homeowners and builders choose the right system.
1. Climate Suitability
One of the primary differences between ERVs and HRVs is their suitability for different climates:
- ERVs are ideal for humid or temperate climates. They transfer both heat and moisture between the incoming and outgoing air, allowing them to retain humidity indoors during winter and reduce it during summer. This feature is particularly useful in humid climates, where excessive moisture can lead to mold and mildew.
- HRVs, on the other hand, are better suited for colder, drier climates. They transfer only heat, making them efficient at recovering warmth during the winter months. However, they do not manage humidity, so they may not be the best choice in areas with high humidity levels or fluctuating seasons.
2. Humidity Control
ERVs have the added advantage of controlling indoor humidity, which can improve comfort and protect your home:
- In the summer, ERVs reduce the amount of humid outdoor air entering the home, preventing excess moisture from building up indoors.
- In the winter, they help retain some of the moisture indoors, preventing the air from becoming overly dry, which can cause discomfort, dry skin, and damage to wood floors and furniture.
HRVs, however, simply exchange warm indoor air with cooler outdoor air without altering the humidity levels, making them more effective in cold and dry environments but less suitable for managing humidity.
3. Energy Efficiency
Both ERVs and HRVs are designed to improve energy efficiency, but they do so in slightly different ways:
- ERVs transfer both heat and moisture, which means less energy is needed to maintain comfortable indoor temperatures and humidity levels. This can be particularly beneficial in climates with high humidity.
- HRVs focus solely on heat transfer, making them incredibly efficient in cold climates where the primary concern is conserving heat. They prevent the loss of warm air while bringing in fresh air, ensuring that your heating system doesn’t need to work overtime.
4. Installation Complexity
In terms of installation, both systems are relatively straightforward for professionals, but there are a few factors to consider:
- ERVs might require more attention to moisture management, as the system will be handling not only heat exchange but also the movement of humidity. This can slightly increase installation complexity, particularly in areas where mold and condensation are concerns.
- HRVs, on the other hand, are generally simpler to install in cold climates, where humidity levels are less of a concern.
5. Maintenance Requirements
Both ERVs and HRVs require regular maintenance to function efficiently, but there are some differences:
- ERVs: In addition to regular filter changes, ERVs need to have their moisture transfer cores inspected and cleaned to ensure efficient operation.
- HRVs: Maintenance for HRVs focuses more on cleaning the heat exchange core and checking for any buildup of dust or debris, which can hinder performance.
6. Cost Considerations
The costs of purchasing and installing an ERV or HRV vary depending on the size of your home, the complexity of installation, and the brand. However, there are a few general trends:
- ERVs tend to be slightly more expensive than HRVs due to their ability to manage both heat and humidity. However, in regions where humidity control is critical, the added cost can be offset by savings on heating, cooling, and moisture management over time.
- HRVs may have a lower upfront cost but are best suited for homes where heat recovery is the priority, such as colder climates.
7. Choosing the Right System for Your Home
When choosing between an ERV or HRV, consider the following factors:
- Climate: If you live in a region with high humidity, an ERV is likely the better option. In colder, drier climates, an HRV will perform more efficiently.
- Indoor Comfort: If maintaining a stable indoor humidity level is important for your comfort or home preservation (such as preventing wood damage), an ERV will provide more benefits.
- Energy Efficiency: Both systems improve energy efficiency, but the specific savings will depend on your climate and ventilation needs. If your priority is preventing heat loss in the winter, an HRV might offer better energy savings.
By understanding these differences, you can choose the system that best suits your home’s unique climate and indoor air quality needs. Whether you opt for an ERV or HRV, both systems offer valuable solutions to improve ventilation while maintaining energy efficiency.
If your home needs ventilation, a ductless HRV could be an excellent choice for you, especially if you have limited space to install ducts. Apart from the energy savings they offer, ductless HRVs are designed to fit inconspicuously into your home, with their low profile and quiet operation. A great example of this is the container cottage that we featured previously on Rise. In a house made of containers, there was not much space for ducts in the rooms. The architect chose to go with ductless HRVs, and they love the results.
