The choice between an HRV or ERV depends heavily on your climate. Because Broken Arrow sees both high summer temperatures and cold winters, the right choice isn't so obvious around here. Getting a better understanding of how these ventilation systems work will help you decide.
How HRVs and ERVs Differ
A heat recovery ventilator (HRV) uses exhaust fans to draw out stale, humid indoor air and supply fans to bring in fresh, outdoor air. Equal amounts of air are removed and replaced to provide continuous, balanced airflow.
Because just blowing out indoor air and letting in outdoor air would waste energy, an HRV contains a heat exchanger to minimize this waste. In winter, the heat exchanger collects heat energy from the outgoing warm air and transfers it into the incoming outdoor air, effectively pre-warming the air. In summer, it does the opposite to pre-cool the incoming air.
Energy recovery ventilators (ERVs) work the same way as HRVs with one difference. Their heat exchanger also transfers moisture. This means ERVs let in less humidity than HRVs in summer.
Making Your Choice
In a cold winter or mixed climate, an HRV is usually the best option. That said, there are other factors to consider when choosing between an HRV or ERV. These include the age and energy efficiency of your home, its size and the number of occupants. A large, drafty house with only two or three people is more likely to suffer from uncomfortably low humidity in winter, particularly in the drier parts of town. In this situation, an ERV may be a better choice.
Modern homes are built to be airtight, increasing their tendency toward high humidity. These homes, especially the smaller ones, are best suited to HRVs. Older homes were often intentionally built with cracks to provide airflow, meaning they're more likely to become dry during our cold winters. This makes some older homes better candidates for ERVs, although air sealing should also be considered.
For help deciding whether an HRV or ERV is right for your home, contact the pros at Air Assurance in the Broken Arrow area.
Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). Credit/Copyright Attribution: “Jezper/Shutterstock”