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HRV vs. ERV: What are they and what do they do?

Jun 12, 2018


We can get some drab weather in Northern Virginia, especially in-between seasons — overcast skies, scattered showers, high humidity. If you ever notice that the air in your home has a damp feel or a musty smell, you might want to consider installing a ventilation system. 
Whole-house ventilation is a mechanical system that draws fresh air in and pushes stale air out of your home. 
There are many benefits to installing a home ventilation system — it can eliminate allergens, reduce excess moisture, and help cut heating and cooling costs. 
There are two types of mechanical ventilation systems: heat-recovery ventilators (HRV system) and energy-recovery ventilators (ERV system). Let’s explore how these systems work, the differences between them, and how to choose the right system for your home. 


What is a heat-recovery ventilator?

An HRV system consists of two air ducts: one that carries fresh air in and one that carries stale air out. Both incoming and outgoing air pass through a heat exchanger, a device that allows heat to transfer from one airstream to the other without the two airstreams actually coming in contact with one another. 
Depending on the temperature and humidity level during a particular time of year, the speed of the fan in each air duct can be adjusted so that the air brought into the house is more efficiently heated or cooled. 

HRV Benefits

HRVs are able to remove stuffy air from rooms with limited air flow, like basements, laundry rooms, and bathrooms. They also drive fresh air into more frequently used rooms like bedrooms and living rooms to maximize comfort. 
On a hot summer day in Northern Virginia, you can use an HRV to precool the fresh air coming into your house through your air conditioning system. In the winter, HRVs are able to recover heat energy through the heat exchanger to preheat the fresh air, which can help you cut heating costs. 
Since the two airstreams never come in direct contact with one another in the heat exchanger, the incoming fresh air is not contaminated by the exhaust air.

What is an energy-recovery ventilator?

ERV systems work the same way HRVs do — one air duct pushes stale air out of your home while the other draws fresh air in — but ERVs also manage humidity. 
An ERV system can remove or retain humidity in your home by transferring moisture from one airstream to the other. 
An ERV’s humidity control function not only increases comfort but also keeps the heat exchanger core warmer, which helps it run more efficiently. 
ERV Benefits
An ERV system is most useful in areas with extreme weather — hot, humid summers and cold, dry winters. 
In the summer, an ERV system can reduce humidity in your home, which helps prevent mold growth and keeps air feeling fresher. 
In the winter, ERVs allow the air in your home to retain some moisture, which helps prevent dry skin and nosebleeds that can occur when the air is too dry. 

HRV vs. ERV — which is better?

The key differentiator between an HRV and an ERV is the way the heat exchanger works — HRVs only exchange heat while ERVs exchange both heat and water vapor. 
Here are some factors to consider when deciding which type of ventilation system is right for your home:
Climate. If you live in an area with more extreme weather, like dry winters and muggy summers, an ERV system might be a better choice for your home. However, spring and fall weather in Northern Virginia is relatively mild, so the local climate isn’t the only factor to consider when making this decision.
Family Size/Lifestyle. Whether you decide to install an HRV system or an ERV system could be dependent on your family’s habits. Air retains more moisture when you have a larger family living in a smaller home — more people are sharing space, more water is being used, etc. 
In addition, families who cook often generate more heat and moisture in the kitchen than those who dine out.
Specific Needs. If you or a family member suffers from allergies, asthma, or a skin condition, air that is too dry could exacerbate symptoms, which means an ERV could be the right option for your family.
Regardless of whether you opt for an HRV vs. ERV, both types of ventilators can help your HVAC system work more efficiently, saving you money in the long run.


Breathe easier with better ventilation. 
Make sure that the air in your home is fresh and that stale air is always pushed out. Consider investing in an HRV or ERV system. Contact our Warrenton HVAC professionals at 1-877-740-6657 or schedule an appointment online today.


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