Will an HRV core frost in −30 °C climates, and how do you prevent it?

Trade Talk
1

Will an HRV core frost in −30 °C climates, and how do you prevent it?

3 Likes
2

Yep, HRVs might freeze when it’s as cold as −30 °C, but the good ones have stuff inside to stop that from happening. If you’re in a place with really cold weather, be sure to pick an HRV that’s made for those temps—maybe one with a preheater and keep it in good shape.

1 Like
3

Definitely
An HRV core can frost in −30 °C climates due to moisture freezing inside. To prevent this, use a unit with a defrost cycle or a preheater to warm incoming air. Ensure balanced airflow, proper drainage, and regular maintenance. In some cases, an ERV may be a better option depending on humidity needs.

4

Yes in 30 °C, an HRV core can frost.

Prevention usually means built-in defrost cycles, pre-heaters, or slightly mixing warm indoor air with incoming fresh air.

1 Like
5

HRV cores can indeed frost up in extremely cold climates like -30 °C, especially when indoor humidity levels are high. Frost buildup occurs when the outgoing air’s moisture freezes onto the core, restricting airflow and reducing the system’s efficiency.

Prevention Strategies:

  1. Defrost Cycle: Most modern HRVs have an automatic defrost cycle that temporarily stops the intake of outdoor air to allow the core to warm up.

  2. Preheating Supply Air: Preheating the incoming air can prevent frost formation, but it’s not always energy-efficient unless using a free heat source like a geo loop.

  3. Recirculation Mode: Some HRVs switch to recirculation mode to warm the core and prevent frost buildup.

  4. ERV vs HRV: ERVs are generally less susceptible to frosting due to moisture transfer between fresh and stale air, reducing the need for defrosting.

1 Like