Renew & Retrofit Homes with Indoor Air Quality

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Comfort

July 30

As the demand for better indoor air quality and energy efficiency grows, integrating balanced ventilation into existing buildings has become critical.

Ventilation in retrofitted homes and light commercial spaces can dramatically enhance indoor air quality while reducing energy costs.

This article will explore how engineers, builders, and HVAC contractors can successfully integrate these systems into existing blueprints, focusing on residential and light commercial projects.

Understanding HRV and ERV Systems

Fresh air appliances with heat and energy recovery systems (HRV and ERV) are designed to improve indoor air quality by exchanging stale indoor air with fresh outdoor air. Heat recovery systems recover heat from the exhaust air to preheat the incoming air, while energy recovery systems transfer both heat and moisture, providing a more balanced indoor humidity level.

Heat recovery ventilators (HRVs) are ideal for colder climates where maintaining heat is crucial, while energy recovery ventilators (ERVs) work best in more humid climates by balancing moisture levels. The choice between an HRV/ERV depends on the specific needs of the building and its location.

Fresh air from outside

Stale air to outside

Stale air from inside

Fresh air to inside

The Importance of Retrofitting

Retrofitting older buildings that lack mechanical ventilation presents several challenges, including poor indoor air quality and inefficient energy use due to less airtight construction and outdated HVAC systems. Without mechanical ventilation, there's a risk of inadequate fresh air supply, leading to elevated levels of indoor pollutants, discomfort, and increased energy costs. Addressing these issues is crucial to enhance occupant health and reduce energy usage.

Implementing residential ventilation systems, such as Energy (ERVs) and Heat Recovery Ventilators (HRVs), is essential. These systems provide balanced ventilation by continuously supplying fresh air and removing pollutants.

ERVs recover both heat and moisture, making them ideal for maintaining indoor humidity levels, while HRVs focus solely on heat recovery, beneficial in colder climates. Both systems help optimize energy use and improve indoor air quality, contributing to better comfort and lower energy bills in retrofitted buildings.

The benefits of using fresh air appliances with heat and energy recovery are multifaceted. They significantly improve indoor air quality by continuously supplying fresh air and effectively removing pollutants. Additionally, these systems reduce the demand for heating and cooling systems through energy recovery, helping to maintain comfortable indoor temperatures with minimal energy use.

This can result in substantial cost savings on energy bills over time. Moreover, retrofit projects with enhanced indoor air quality often lead to increased property values and improved occupant comfort, highlighting the long-term advantages of integrating these advanced ventilation solutions into existing buildings.

Steps to Integrate HRV and ERV Systems into Existing Blueprints

Initial Assessment

Begin by evaluating the current HVAC system and the building’s ventilation needs. Identify optimal locations for installing the fresh air appliance with heat or energy recovery (HRV/ERV), considering space constraints and airflow patterns. Recommendations for optimal locations might include, but are not limited to:

Residential (Single and Multi-Family)

Attics or Mechanical Rooms

These areas are often ideal for a fresh air appliance with heat or energy recovery (HRV/ERV) as they provide sufficient space and central access to the entire home’s ductwork.

Basements

Another good option, especially if the basement houses other HVAC equipment, making it easier to integrate the new system.

Closets or Utility Rooms

In smaller homes or apartments, a closet or utility room can be a practical location, provided there's adequate ventilation and space for duct connections.

Light Commercial

Ceiling Spaces or False Ceilings

In office buildings and retail locations, ceiling spaces can accommodate compact fresh air appliances with heat or energy recovery (HRV/ERV) without taking up valuable floor space.

Mechanical Rooms or Rooftop Units

These locations are suitable for larger systems that need to serve multiple zones or large open areas.

System Design

Customize the fresh air appliance with heat or energy recovery (HRV/ERV) to fit the climate and the building’s specific requirements. Plan for ductwork and electrical needs, ensuring minimal disruption to the existing structure. Recommendations include:

Ductwork Planning

Ensure that the new ductwork integrates seamlessly with existing HVAC ducts, minimizing the need for extensive modifications. Use flexible ducts where possible to simplify installation.

Electrical Needs

Coordinate with an electrical engineer or electrician to ensure the HRV/ERV has a dedicated power supply and complies with local electrical codes.

Installation Process

Install New Ductwork and Ensure Proper Sealing

Install ductwork according to the designed plan, ensuring all joints and connections are properly sealed to prevent air leaks.

Place the HRV/ERV Unit in the Designated Location

Secure the unit in the chosen location, ensuring it is level and accessible for future maintenance.

Connect the Appliance to the Ductwork and Electrical System

Connect the fresh air appliance with heat or energy recovery (HRV/ERV) to the ductwork and ensure all connections are airtight. Hook up the electrical supply and any necessary control systems.

Test the System to Ensure Balanced Airflow and Proper Operation

Perform a thorough check to balance the airflow, ensuring that the system provides adequate ventilation to all areas of the building.

Testing and Commissioning

After installation, perform thorough testing to confirm the system is balanced and functioning correctly. If not part of an ongoing service plan, provide ongoing maintenance tips to the home or building owner to ensure long-term efficiency and performance.

Here are some quick recommendations:

Initial Testing

Measure airflow rates and adjust the system to ensure even distribution throughout the building.
Check the operation of all controls and safety devices, including smoke detectors, high-temperature limit switches, pressure switches, condensate overflow switches, and CO2 and TVOC sensors, for example.

Ongoing Maintenance:

Regularly clean and replace filters to maintain air quality and system efficiency.
Schedule periodic inspections to identify and address any issues before they affect performance.

Case Studies and Examples

These case studies showcase successful retrofitting projects that have integrated advanced ventilation systems to improve indoor air quality and energy efficiency.

Residential Project: 32 Mill Street Net-Zero Energy Retrofit

In Kitchener, ON, the Kitchener Urban Native Wigwam Program (KWUNP) and the University of Waterloo’s Warrior Home team retrofitted a surplus home at 32 Mill Street.

The project included a rooftop photovoltaic (PV) system, advanced insulation, and a vapor variable air barrier, achieving a HERS score of 37 with PV and reducing energy use to less than 2,000 kWh per year.

An ATMO™ fresh air appliance with energy recovery (ERV) was installed to meet National Building Code (NBC) requirements, ensuring excellent indoor air quality and a HERO® HS300 HEPA Filtration System was added for enhanced air purification.

This retrofit provides a healthy and energy-efficient living environment for an Indigenous family at an affordable rate.

Multi-Family Project: Le Divin in Beauport, Quebec

Le Divin, a former convent in Beauport, QC, was transformed into 280 contemporary condominiums while preserving its historic charm. The renovation included modern amenities like high ceilings, balconies, and superior soundproofing, along with common spaces such as a fitness room, indoor virtual golf lounge, and a preserved grand chapel.

To meet the 2015 National Building Code (NBC) with Quebec’s amendments, each condo was equipped with Fresh Air Appliances with heat recovery ventilation (HRVs), ensuring compliance with ANSI/ASHRAE 62.1 ventilation standards.

These appliances with heat recovery provide fresh air to living spaces and temper incoming air with exhaust air to maintain energy efficiency, controlled by user-friendly touchscreen IAQ controls with ECO mode, cutting ventilation energy consumption by up to 25%.

Best Practices for Engineers, Builders, and HVAC Contractors

Best Practices for Engineers, Builders, and HVAC Contractors include early collaboration to ensure seamless retrofitting projects. Comprehensive planning covers all installation aspects, minimizing potential issues.

Staying informed about the latest technologies and regulations through continuous education is crucial for adopting best practices and innovative solutions.

Clear communication with building owners and occupants about retrofitting benefits, detailed timelines, and realistic expectations ensures a smooth project execution.

Future Trends in HRV and ERV Integration

Future trends in HRV and ERV integration point towards significant technological advancements like smart controls and advanced filtration systems, poised to improve system efficiency and user experience. These innovations align with sustainability goals, helping to reduce carbon footprints and meet green building standards.

Looking ahead, the market for HRV and ERV systems in both residential and commercial sectors is anticipated to expand, fueled by heightened awareness of their benefits for indoor air quality and energy efficiency.

Reflections

Integrating HRV and ERV systems into existing blueprints offers significant benefits in terms of air quality, energy efficiency, and occupant comfort.

Engineers, builders, and HVAC contractors play an important role in this transformation. By adopting these advanced ventilation systems, they can contribute to healthier, more energy-efficient buildings.

Technical Resources

ASHRAE Guidelines on Ventilation and Indoor Air Quality

EPA's Indoor Air Quality Tools for Schools