Who this guide is for
- Homeowners planning whole-home ventilation
- People comparing recovery ventilation options
- Owners of tightly sealed or newer homes
- Anyone wanting to brief a ventilation specialist
What both systems do
Both HRV and ERV continuously exchange stale indoor air for fresh outdoor air while recovering energy from the outgoing air, so you ventilate without simply throwing away heat. The shared goal is fresh air with less energy waste.
Their common purpose is why they are often considered together.
- Both supply fresh air and extract stale air
- Both recover energy from outgoing air
- Both aim to ventilate efficiently
The key difference: moisture
The main distinction is how each handles humidity. An HRV transfers heat between the airstreams, while an ERV also transfers a degree of moisture. This makes their behaviour differ in how they affect indoor humidity.
Because moisture behaviour is the core difference, climate and household humidity become central to the decision.
- HRV: transfers heat between airstreams
- ERV: transfers heat and some moisture
- The moisture handling is the defining difference
What shapes the choice
Climate, how humid the home tends to be, and how it is used all influence which system suits. There is no universal answer; a home in one climate may favour different behaviour than a home in another.
This is precisely the judgement a ventilation professional brings, assessing your specific home and conditions.
Design, sizing, and installation
Whichever system, performance depends heavily on correct design, sizing, and installation, including ductwork and balancing. A poorly designed system underdelivers regardless of type, which is why this work is specialist.
Route system design and installation to qualified professionals rather than choosing on type alone.
- Correct sizing and ductwork matter as much as type
- Balancing affects real-world performance
- Route design and installation to professionals
HRV vs ERV planning checklist
- 1Understand that both ventilate and recover energy
- 2Note the moisture-handling difference
- 3Consider your climate and its humidity
- 4Think about how humid the home tends to be
- 5Factor how the home is used
- 6Recognise that design and sizing drive performance
- 7Avoid choosing on type alone
- 8Consult a ventilation professional for your home
Common mistakes to avoid
- Choosing on type without considering climate and humidity
- Assuming one system is universally superior
- Ignoring how design and sizing affect performance
- Overlooking ductwork and balancing
- Treating moisture behaviour as irrelevant
- Skipping professional assessment of the home
When to involve a professional
- System design, sizing, and installation should be handled by qualified professionals.
- Which system suits depends on climate and home; requirements vary by location.
- Ventilation interacts with moisture and the envelope, requiring professional judgement.
- Costs and timelines vary by home and system.
Frequently asked questions
Questions readers ask about this topic
What is the difference between HRV and ERV?
Both ventilate while recovering energy from outgoing air. The key difference is moisture: an HRV transfers heat between airstreams, while an ERV also transfers a degree of moisture. That difference in humidity handling is what sets them apart.
Which one is better for my home?
Neither is universally better. The right choice depends on your climate, how humid the home tends to be, and how it is used. A ventilation professional can assess your specific conditions rather than applying a one-size answer.
Does climate really change the decision?
Yes. Because the systems differ in how they affect indoor humidity, climate and household moisture become central to which suits. A home in one climate may favour different behaviour than a home in another.
Is the system type the most important factor?
Not on its own. Correct design, sizing, ductwork, and balancing strongly influence real-world performance, so a well-designed system matters as much as the type. This is why installation belongs to qualified professionals.
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