Ventilation Guide
ERV vs. HRV: Which Energy Recovery Ventilator Fits Your Home?
By Dioclecio Gomes, Founder & Owner3 min readUpdated October 8, 2026
An HRV (heat recovery ventilator) and an ERV (energy recovery ventilator) both swap stale indoor air for fresh outdoor air while recovering heat through a heat exchanger. The difference is moisture: an ERV also transfers water vapor, which helps indoor humidity stay more constant. The Department of Energy says most ERVs recover about 70% to 80% of the sensible energy in the exiting air.
An energy recovery ventilator becomes more important as a house gets tighter. Replacing drafty windows and siding saves energy, but it also cuts the accidental fresh air an old house used to get. The explanations below come from the Department of Energy, Green Building Advisor and Panasonic.
What Do HRVs and ERVs Do?
The DOE contractor guide calls an HRV or ERV the best way to provide balanced ventilation. Both bring in fresh air and exhaust stale air in equal amounts, and both use a heat exchanger so the outgoing air warms (or, in summer, cools) the incoming air. They are whole-house systems that can share a central furnace air handler and ducts or run on their own small duct system.
What Is the Difference Between an ERV and an HRV?
| HRV | ERV | |
|---|---|---|
| Transfers | Heat only | Heat and water vapor |
| Heat recovery | About 70% (Panasonic) | About 70% to 80% (DOE); up to 90% sensible (Panasonic) |
| Winter humidity | Lets indoor moisture go outside | Keeps some moisture indoors |
| Also called | Heat recovery ventilator | Energy or enthalpy recovery ventilator |
The DOE energy basics page says the moisture transfer in an ERV helps the humidity inside the home stay more constant.
Which One Is Better for a Massachusetts Home?
For most homes here, an ERV. Building scientist Allison Bailes writes in Green Building Advisor that in a cold climate, bringing in outdoor air without moisture exchange can leave indoor humidity extremely low in winter, because cold air is dry air, and that on the basis of climate HRVs only make sense in mild climates. He adds one exception: the more people in a small, airtight space, the more an HRV may help dry it out.
Panasonic takes a more traditional view, recommending HRVs for cold, dry regions and ERVs for humid or mixed climates. Massachusetts has cold winters and humid summers, so many homes lean toward an ERV, but the right answer depends on how tight the house is and how many people live in it.
Tightening up your home?
New windows, siding and insulation change how a house breathes. Ask about ventilation during your free remodeling estimate.
Ask About Fresh Air SystemsWhat Does Installation Involve?
The DOE guide lists the trade-offs: ERVs and HRVs have a higher first cost than simple exhaust fans and need planning for the unit, vents and duct locations. That planning is easiest during a remodel, when ceilings and walls are open. Panasonic suggests sizing for 0.35 to 0.70 air changes per hour and either running dedicated ducts or integrating with an existing air handler.
How Do You Maintain an ERV or HRV?
Panasonic recommends checking filters every three to six months and inspecting the core once a year, so install the unit where both are easy to reach. The DOE guide also stresses following the manufacturer's installation directions, especially for ERVs in humid climates.
The Bottom Line
Both ventilators bring in fresh air and recover most of the heat; an ERV also manages moisture. For a tight Massachusetts home, an ERV is the common pick. Plan the ducts while the walls are open. Ask About Fresh Air Systems
FAQ
What is an energy recovery ventilator?
A balanced ventilation system that swaps stale indoor air for fresh outdoor air and uses a heat exchanger to recover heat and some moisture. The DOE says most ERVs recover about 70% to 80% of the sensible energy in the exiting air.
Is an ERV or HRV better in a cold climate?
Green Building Advisor argues for an ERV, because cold outdoor air is dry and an HRV can leave indoor humidity very low in winter. An HRV can still suit a small, airtight home with many occupants that runs humid.
Can an ERV use my existing ductwork?
Yes. The DOE guide says these ventilators can share a central furnace air handler and duct system or have their own duct system.
How often should ERV filters be changed?
Panasonic recommends checking filters every three to six months and inspecting the core yearly.