What Is an ERV HVAC System and How Does It Work?

An ERV system can lower HVAC energy costs and keep out air contaminants

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Photo: Wirestock / Adobe Stock
spacious interior living room design with grey sofa
Photo: Wirestock / Adobe Stock
Highlights
  • An ERV system uses two fans to draw out stale air and bring in fresh air.

  • ERV systems keep out air contaminants and odors.

  • ERV systems can be noisy and expensive to install.

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An Energy Recovery Ventilator (ERV) is the air exchanger that connects to your HVAC system to pull fresh, clean air into your home and remove unclean, cycled air. ERV in HVAC is also known as an air exchanger or an ERV ventilation system. If you need help identifying or replacing this crucial component, hire an HVAC professional. Let’s dig into the benefits and drawbacks of an ERV system.

What Is an ERV HVAC System?

An ERV HVAC system is an energy recovery ventilator, and it is also referred to as an ERV air exchanger or ERV ventilation system. 

But how does an HVAC ERV system work? These systems are connected to your overall HVAC system to circulate fresh air and help your home retain heat during cold weather by ventilating your home in a way that prevents heat from escaping in the process. They also keep out air contaminants and allergens.

How an ERV System Works

An ERV system uses two fans: one fan to pull fresh air into the building and another fan to push the stale air out. A heat exchanger works to transfer heat and moisture from one air stream to the other, preventing any loss of heat from this ventilation method.

Also, an ERV system captures contaminants, allergens, and other pollutants as the outside air enters the home.

How an ERV system works illustrated, with fresh outside air being brought inside the home through the heat exchanger

ERV vs. HRV Systems

ERVHRV
Transfers heat and moistureTransfers heat
Better for a small familySlightly more efficient
Works great with boilers Works great with baseboard heaters

Both ERV and HRV systems remove stale air from the home and pump fresh air into the home for temperature control and comfort. The main difference is that ERV systems transfer heat and moisture to keep the home warm, while HRV systems (heat recovery ventilators) only transfer heat. On the flip side, HRV systems are slightly more efficient. An ERV system’s ability to transfer moisture can make a big difference in controlling indoor humidity levels, especially during hot summer months and dry winter months. 

Benefits of Installing an ERV System

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Photo: Nataliia / Adobe Stock

An ERV system has multiple key benefits that make it attractive to homeowners.

Energy Efficiency

Some manufacturers claim that 99% of heat energy from the stale air is transferred to the incoming air. This makes it a far more energy-efficient way to ventilate your home compared to, say, opening a window. As a result, you may enjoy lower energy bills, and your home will stay at a comfortable temperature in the process.

"Energy efficiency should be a top priority for any homeowner. This does require an initial investment, but it pays off in the long run with lower energy bills. Plus, there are often incentives and rebates available from local utility providers for making energy-efficient upgrades."

Bill Taylor, HVAC Contractor Manager, South Jersey Gas & Elizabethtown Gas

HVAC Performance

ERV systems will keep the ductwork and filters in your HVAC system cleaner for longer. This equates to decreased maintenance requirements on your part and a longer lifespan for your HVAC system.

Fewer Contaminants

Stale air that builds up in your home can be loaded with contaminants and allergens that can irritate your airways or just lower the air quality in general. Also, odors can build up over time. An ERV system will ventilate your home to keep fresh air circulating.

Lower Humidity

ERV systems don't just regulate heat. They also lower humidity by between 30% to 50%. This keeps your home comfortable and may prevent damage from mold and mildew over time.

Downsides of Installing an ERV System

While there are many benefits to ERV systems, you should also be aware of some downsides before making the choice to install one.

High Electricity Usage

While ERV system manufacturers claim that an ERV system will lower your energy bill, that is not always the case. Some ERVs may use more electricity than they save you in terms of heating and cooling, so these types of systems may be ideal for people who spend a lot on heating and cooling each year and are looking for ways to lower their costs. 

For those with more modest heating and cooling bills, an ERV system may not save money. 

Noise

ERV systems work hard to keep air circulating, and that means they can be noisy. They pump air at high velocity, and if you install them too close to living areas, the sound may bother you. You can mitigate this by installing it somewhere that won't bother you.

Cost

An ERV system may save you money in the long run, but the initial installation may cost $2,000 or more. Contact a local HVAC company to get a customized quote for a system for your home. 

Indoor Air Quality May Not Need Improvement

Not all homes are filled with contaminants. Before making the decision to install an ERV system, consider testing your current air quality to determine if an ERV system may be needed. 

The cost of indoor air quality testing is about $400 on average. If your air quality is not terrible, it may be better to follow some tips to improve indoor air quality.

Frequently Asked Questions

It’s a better use of energy (and your money) NOT to run an ERV system all the time. Most experts recommend that you cycle your ERV system on and off throughout the year. However, the recommended advice could change based on your climate, the number of people in your home, the size and style of your home, and your heating and cooling system. Contact a local pro for more specific advice.

Yes. You need four ducts if you’re going to install an ERV system. These include an indoor and outdoor supply, an outdoor exhaust, and an indoor return. You may be able to use existing ductwork for your ERV if you have a furnace. Six-inch duct material is the standard for installing an ERV system.

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