Fresh air that doesn’t arrive freezing.
A sealed house needs fresh air, and an open window lets in whatever the weather is. Hero ERV swaps stale indoor air for outdoor air all day, and the outgoing air warms or cools the incoming air on the way through. Drag the slider to see what reaches your rooms.
Assumes a 70°F house and 70% heat recovery, which is typical for ERV cores. Real numbers depend on the unit and the airflow.
A tight house needs a way to breathe
Older homes leaked enough air to ventilate themselves, and they paid for it in heating and cooling. Newer and retrofit homes are sealed much tighter. That’s good for the bill, but the air inside doesn’t get replaced unless something replaces it.
Mini splits, heat pumps and furnaces don’t fix this. They heat and cool the same indoor air over and over. An ERV is the part that brings fresh air in.
- Stuffy bedrooms
- CO₂ builds up overnight with the door shut. Steady fresh air keeps it down.
- Dry winter air
- An ERV holds on to indoor moisture instead of sending it out with the exhaust.
- Sticky summers
- It sheds much of the outdoor humidity before it gets in, so the AC has less to deal with.
- Smells that hang around
- Cooking, pets and bathrooms get cleared all day, not only when someone opens a window.
How an ERV works
Stale air goes out
Air is drawn from the rooms that get stuffy: kitchens, bathrooms and laundry.
It passes through the core
Outgoing and incoming air run through separate channels and never mix. Heat and moisture cross the thin walls between them.
Fresh air comes in
Filtered outdoor air goes to bedrooms and living spaces, already close to room temperature.
ERV or HRV?
Both are balanced ventilators with a recovery core. The difference is what the core passes across.
| ERV | HRV | |
|---|---|---|
| Recovers heat | Yes | Yes |
| Recovers moisture | Yes | No |
| Winter indoor air | Stays more comfortable, less dry | Tends to get drier |
| Summer humidity | Keeps much of it outside | Brings it in with the fresh air |
| Usual fit | Humid summers, dry winters, most mixed climates | Very cold climates where the house runs damp inside |
Questions
What does an ERV do?
An energy recovery ventilator pulls stale air out of the house and brings the same amount of fresh outdoor air in. The two streams pass each other inside a core that moves heat and moisture from one to the other, so the incoming air shows up closer to indoor temperature and humidity.
What is the difference between an ERV and an HRV?
An HRV (heat recovery ventilator) only transfers heat. An ERV transfers heat and moisture, which helps keep winter air from getting too dry and keeps summer humidity from being dragged indoors.
Do I need an ERV if I have a mini split or furnace?
Heating and cooling equipment recirculates the air already in the house. It doesn't bring in fresh air. An ERV handles ventilation, so it works alongside a mini split, heat pump or furnace rather than replacing it.
Does an ERV raise my energy bill?
It runs small fans, so it uses some electricity. The point of the recovery core is that the fresh air arrives already partly heated or cooled, which costs much less than opening a window or running a plain exhaust fan.
Ask about Hero ERV
Tell us about your house (size, climate, what you heat and cool with) and we’ll get back to you.
Email hello@heroerv.com