Energy Recovery Ventilation: What Is an ERV and Do I Need One?

Indoor air quality (IAQ) is a top priority for homeowners—especially as modern homes become tighter sealed to boost energy efficiency. But here’s the catch: less air leakage means stale indoor air, excess moisture, and pollutants get trapped inside. That’s where Energy Recovery Ventilators (ERVs) come in. But what exactly is an ERV, how does it work, and is it a must-have for your home? Let’s break it down, so you can decide if this ventilation solution is right for you.

What Is an Energy Recovery Ventilator (ERV)?

An ERV is a type of balanced mechanical ventilation system designed to replace stale indoor air with fresh outdoor air—while recovering energy (and moisture) from the air being expelled. Unlike simple exhaust fans (which only remove air) or supply fans (which only bring in air), ERVs maintain balanced air pressure in your home. This prevents issues like drafts, moisture buildup, or pollutants being pulled into your living space from crawl spaces or attics.

The key feature that sets ERVs apart from other ventilation systems (like HRVs, which we’ll touch on later) is their ability to transfer both heat and moisture between incoming and outgoing air streams. This dual transfer makes ERVs versatile, working hard to keep your home comfortable year-round—no matter the climate.

How Does an ERV Work?

ERVs operate using a specialized energy recovery core (often made of porous materials like polymer or ceramic) that acts as a bridge between two separate air streams: one for stale indoor air and one for fresh outdoor air. The two air streams never mix—this is critical for maintaining IAQ, as it prevents pollutants from the outgoing air (like dust, pet dander, or VOCs) from re-entering your home.

Here’s a step-by-step breakdown of its year-round operation:

In Winter

Cold, dry outdoor air enters the ERV, while warm, moist indoor air (from cooking, showering, or breathing) is pulled into the unit. The energy recovery core transfers heat and moisture from the indoor air to the outdoor air. This pre-heats and humidifies the incoming air, so your furnace doesn’t have to work as hard to keep your home warm—and you avoid the discomfort of overly dry air (think nosebleeds, cracked skin, or static electricity).

In Summer

Warm, humid outdoor air is drawn into the ERV, and cool, dry indoor air (conditioned by your AC) is expelled. The core transfers heat from the outdoor air to the indoor air (cooling the incoming air) and absorbs excess moisture from the outdoor air (dehumidifying it). This lightens the load on your air conditioner, saving energy and preventing that sticky, muggy feeling inside your home.

ERV vs. HRV: What’s the Difference?

You might have heard of Heat Recovery Ventilators (HRVs) as a similar option—and while they’re both balanced ventilation systems, their key difference lies in moisture handling:

• ERV: Transfers both heat and moisture (ideal for humid climates or mixed climates with extreme temperature swings).

• HRV: Transfers only heat (no moisture transfer—better for extremely cold, dry climates where adding moisture could cause window condensation or mold).

For most homeowners, ERVs are the more versatile choice because they address both temperature and humidity, making them useful in all seasons.

Do You Need an ERV for Your Home?

Not every home requires an ERV—but if you check any of the boxes below, it’s likely a worthwhile investment. Let’s look at the top signs you need an ERV:

1. You Live in a Humid or Mixed Climate

If your area has hot, humid summers (e.g., Florida, Texas, the Southeast U.S.) or year-round humidity (e.g., the Pacific Northwest), an ERV will help dehumidify incoming air in summer and balance moisture in winter. This reduces the risk of mold, mildew, and musty odors—common issues in humid homes.

Even in mixed climates (with cold winters and humid summers, like Illinois or New York), ERVs shine by adapting to seasonal changes, keeping your home comfortable year-round.

2. Your Home Is Tightly Sealed (New or Renovated)

Newer homes or recently renovated homes are built to be airtight (thanks to better insulation, weatherstripping, and double-paned windows) to save energy. But this tight seal traps stale air, moisture, and pollutants. An ERV provides consistent fresh air without sacrificing energy efficiency—solving the “airtight home dilemma.”

3. You Struggle With Indoor Air Quality Issues

If you notice symptoms like allergies, headaches, or stuffiness indoors, or if you have pets, smokers, or use cleaning products/VOCs regularly, an ERV can help. It removes stale air (and the pollutants in it) and replaces it with fresh outdoor air—improving IAQ for you and your family. This is especially important for people with asthma or respiratory sensitivities.

4. You Want to Reduce Energy Bills

By pre-conditioning incoming air (heating/cooling and humidifying/dehumidifying it using energy from outgoing air), ERVs reduce the workload on your furnace and AC. This translates to lower energy bills over time—offsetting the upfront cost of the unit and installation.

When Might You Not Need an ERV?

ERVs aren’t necessary for every home. You can probably skip one if:

• You live in an extremely cold, dry climate (e.g., Northern Canada, Alaska)—an HRV would be a better fit here, as it won’t add excess moisture (which could cause condensation).

• Your home is older and leaky (plenty of natural air exchange)—though sealing air leaks and adding an ERV would still improve efficiency and IAQ.

• You already have a whole-home ventilation system that balances heat and moisture (rare, but some advanced systems offer similar benefits).

Key Tips for Choosing and Installing an ERV

If you decide an ERV is right for you, keep these tips in mind to get the most out of your investment:

• Size It Correctly: Choose an ERV sized for your home’s square footage and number of occupants. An undersized unit won’t provide enough ventilation, while an oversized one will waste energy. A professional can help calculate the right size.

• Prioritize Ductwork: ERVs rely on ductwork to distribute fresh air and remove stale air. If your home doesn’t have existing ducts, ask about ductless options (though they’re less common and may be less efficient).

• Don’t Skip Maintenance: Clean or replace air filters every 3–6 months, and have the energy recovery core inspected annually. This ensures the unit runs efficiently and maintains good IAQ.

• Hire a Pro: While some DIY enthusiasts may attempt installation, ERVs require proper wiring, ductwork integration, and calibration. A licensed HVAC professional will ensure the unit works as intended.

Final Thoughts: Is an ERV Worth It?

For most homeowners—especially those in humid or mixed climates, or with tight, energy-efficient homes—an ERV is absolutely worth the investment. It improves indoor air quality, boosts comfort year-round, and reduces energy bills. Even if you don’t check all the boxes, if you care about breathing cleaner air and extending the life of your HVAC system, an ERV is a smart addition.

If you’re still on the fence, reach out to a local HVAC professional. They can assess your home’s unique needs, climate, and existing systems to help you decide if an ERV is right for you.

Have questions about ERVs or indoor air quality? Drop a comment below—we’re here to help you breathe easier!