HRV vs ERV: Understanding Modern Home Ventilation Systems
Modern homes are built tighter than ever. While this improves energy efficiency, it also reduces natural air exchange. As a result, stale indoor air can linger longer than many homeowners realize.
Heat Recovery Ventilators (HRVs) and Energy Recovery Ventilators (ERVs) are designed to solve that problem — by bringing fresh outdoor air into your home while exhausting stale indoor air.
Understanding the difference between the two is key to choosing the right system for your home.
Why Ventilation Matters in Energy-Efficient Homes
Today’s homes feature:
Sealed building envelopes
High-performance insulation
Reduced air leakage
Improved windows and doors
These improvements reduce heating and cooling costs — but they also reduce passive airflow.
Ventilation systems are designed to:
Replace stale indoor air
Maintain oxygen levels
Reduce lingering humidity
Support healthier indoor environments
Ventilation is different from filtration. Filtration cleans the air already inside your home. Ventilation replaces it.
Both matter — but they serve different purposes.
What Is an HRV (Heat Recovery Ventilator)?
An HRV is a mechanical ventilation system that exchanges stale indoor air with fresh outdoor air while transferring heat between the two air streams.
How It Works:
Stale indoor air is exhausted outside
Fresh outdoor air is drawn in
Heat from outgoing air is transferred to incoming air
Air is distributed through the HVAC system
The key feature of an HRV is heat transfer — not moisture transfer.
HRVs Are Typically Best For:
Colder climates
Homes where winter dryness is common
Situations where heat retention is the priority
In winter, an HRV helps maintain indoor temperatures while still allowing continuous fresh air exchange.
What Is an ERV (Energy Recovery Ventilator)?
An ERV functions similarly to an HRV but transfers both heat and moisture between incoming and outgoing air streams.
How It Works:
Exhausts stale air
Brings in fresh air
Transfers heat AND humidity
Balances indoor moisture levels
Because it manages humidity as well as temperature, an ERV provides more balanced year-round control in many climates.
ERVs Are Typically Best For:
Regions with seasonal humidity changes
Homes with moisture imbalance concerns
Year-round indoor comfort optimization
HRV vs ERV: What’s the Difference?
Here is a simplified comparison:
| Feature | HRV | ERV |
|---|---|---|
| Heat Transfer | Yes | Yes |
| Moisture Transfer | No | Yes |
| Best for Cold Dry Winters | Strong option | Also effective |
| Best for Humidity Balance | Moderate | Better |
| Year-Round Versatility | Seasonal strength | More balanced across seasons |
In Southwestern Ontario, where winters are long and summers can be humid, both systems can work well — but the choice depends on your home’s construction and existing humidity patterns.
Which System Is Better for Ontario Homes?
Ontario experiences:
Cold, dry winters
Humid summer conditions
Increasingly airtight new construction
In older homes with natural air leakage, ventilation may be less urgent.
In newer homes — especially those built to modern efficiency standards — balanced mechanical ventilation becomes more important.
Many homeowners benefit from ERV systems due to their humidity regulation capabilities. However, homes with persistent winter dryness may lean toward HRV systems.
The right choice depends on:
Square footage
Insulation levels
Existing HVAC configuration
Seasonal humidty patterns
Occupant sensitivity
There is no universal answer — only the right answer for your home.
Do HRVs and ERVs Replace Air Purifiers?
No.
Ventilation and purification serve different purposes.
Ventilation replaces indoor air with fresh outdoor air.
Air Purification filters particles from existing indoor air.
An effective indoor air strategy may include both.
If you would like a deeper explanation of what commonly circulates inside modern homes — from particulate matter to chemical compounds — you can read our guide on what is in the air we breathe.
When Should You Consider Installing a Ventilation System?
You may want to evaluate ventilation if you notice:
Persistent stale air
Lingering odors
Excess humidity or condensation
Uneven indoor comfort
New construction or recent renovations
A tightly sealed energy-efficient home
Ventilation is not about overreacting. It’s about ensuring air exchange matches modern building practices.
Does an HRV or ERV Affect Heating and Cooling?
When properly installed, both systems integrate with your existing HVAC system.
They are designed to:
Recover energy from exhausted air
Reduce heating/cooling loss
Improve airflow balance
Professional installation ensures that ventilation enhances comfort without overburdening your system.
Frequently Asked Questions (FAQ)
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Both HRVs (Heat Recovery Ventilators) and ERVs (Energy Recovery Ventilators) exchange stale indoor air with fresh outdoor air. The difference is in what they transfer during the exchange.
An HRV transfers heat only, while an ERV transfers both heat and moisture. ERVs are often preferred in climates with seasonal humidity changes, while HRVs are commonly used in colder, drier conditions. -
Most HRV and ERV systems last between 10 to 15 years when properly maintained. Regular filter replacement and periodic servicing help extend system life and maintain performance.
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In many Ontario homes, yes — particularly in newer, energy-efficient construction. ERVs help balance both temperature and humidity levels, which can improve comfort during humid summers and dry winters. The right system depends on your home’s design and ventilation needs.
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Many systems are designed to run continuously at a low setting to maintain consistent air exchange. Others operate on timers or humidity sensors. The ideal runtime depends on your home’s size, occupancy, and air quality conditions.
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Ontario Building Code requires adequate ventilation in modern residential construction. In many newer homes, mechanical ventilation systems such as HRVs or ERVs are installed to meet these standards. Requirements can vary depending on the age and design of the home.
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Older homes often have more natural air leakage, which can provide passive ventilation. However, if renovations, new windows, or insulation upgrades have made the home more airtight, a mechanical ventilation system may be beneficial.
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When properly installed, HRV and ERV systems integrate with your HVAC system to improve airflow without significantly increasing energy use. Because they recover heat energy during air exchange, they are designed to minimize heating and cooling loss.
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An HRV can help remove excess indoor humidity during winter. An ERV is specifically designed to transfer moisture, helping to balance humidity levels more consistently throughout the year.
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They improve indoor air circulation by replacing stale air with fresh outdoor air. While they do not filter air to the same degree as dedicated air purifiers, they play an important role in maintaining balanced indoor environments.
Schedule a Ventilation Assessment
Every home is different. Before recommending any HRV or ERV system, we evaluate:
Airflow patterns
Existing filtration
Humidity levels
HVAC integration
Building envelope tightness
Ventilation should be assessed — not guessed. Call (519) 686-3595 or fill out the contact form.
