Heat Recovery Cell

A heat recovery cell (also called an HRV core or energy recovery core) is a component of the air handling unit that transfers thermal energy from outgoing exhaust air to incoming supply air. Modern heat recovery cells can recover 70 to 90 percent of the exhaust air's heat, dramatically reducing the energy needed to heat ventilation air during cold months.

Heat recovery is one of the most effective energy-saving technologies in a home. In a Finnish winter, outdoor temperatures can drop to minus 30 degrees Celsius, and without heat recovery, all the energy used to heat indoor air is simply exhausted outdoors. A high-efficiency heat recovery cell can save hundreds of euros per year on heating costs while maintaining comfortable indoor temperatures.

The most common types are plate heat exchangers (crossflow or counterflow) and rotary heat exchangers. Counterflow plate exchangers are the most efficient, reaching 80 to 90 percent recovery rates. Rotary exchangers also transfer some moisture between airstreams, which helps maintain indoor humidity levels during dry winter months.

The heat recovery cell must be cleaned regularly — typically twice a year — to maintain its efficiency. A dirty or clogged cell restricts airflow and reduces heat recovery performance, increasing heating costs. During cleaning, the cell is removed from the unit, washed with warm water, and dried before reinstallation. If efficiency has dropped noticeably, the cell may need professional cleaning or replacement.