In the modern world, houses are built airtight to conserve energy. Constructing this way is a great idea, as it keeps the air-conditioned inside and will lower your energy bill doing so. However, with tightly sealed homes came many nonexistent problems before this new construction method was developed.
Mechanical ventilation systems were developed to introduce fresh air to curb the airtight issue. These include ERV and HRV. However, in the field of indoor air quality, people often get ERV and HRV mixed up. These two terms are not interchangeable, though they have similarities in ventilation systems.
The key difference is that HRV eliminates stale air, while an ERV exchanges both stale air and moisture. This means that it does not get rid of the heat in your home but instead warms up the incoming fresh air to more or less match what you are currently experiencing inside.
What is an ERV?
An ERV (energy recovery ventilator) is an indoor ventilation system that brings in fresh air from the outside. However, even though it brings in fresh air, your ERV does not eliminate all of the stale inside air as you might expect.
Instead, the incoming fresh air mixes with what is currently inside and warms up to roughly match temperature (depending) with the inside air. This is how it recovers energy, hence its name “energy recovery ventilator.”
How does an ERV Work?
The process of an ERV is complex. However, the basics are as follows:
First, a compressor compresses and cools fresh air to approximately room temperature (~75F). Then it sends this cooled air into your HVAC duct through a ventilator. This causes excess humidification inside the home if you do not have a dehumidifier.
The air then goes into the ERV, where it meets the warm exhaust air from your home. The heat exchanger in the ERV transfers energy to the incoming fresh air, and at the same time, moisture is transferred from the
exhaust to the incoming fresh air. Finally, this now-warmed fresh air is sent into your house through another ventilator.
What is an HVR?
An HRV (heat recovery ventilator) is an indoor ventilation system that brings in fresh air from the outside. However, unlike the ERV, it eliminates stale inside air, as you might expect.
How does an HRV Work?
The process of an HRV is also complex, but the basics are as follows:
First, a fan pulls in fresh air from the outside and sends it into an HRV. A heat exchanger then cools the incoming air before entering your home. The moisture blown back in the house causes excess humidification if you do not have a dehumidifier.
The HRV then separates the warm exhaust air from the cold fresh air, and the heat exchanger transfers energy from the warm exhaust to the cold fresh air. Finally, this warmed fresh air is sent into your house through another ventilator.
Pros and Cons of ERV
Now that you understand how ERVs work, weighing the pros and cons of having one in your home is essential.
Pros of ERV
An ERV can help reduce your energy bill by recovering heat from the exhaust air.
- ERVs also help improve indoor air quality by exchanging stale air with fresh air.
- ERVs are an excellent choice for homes with low humidity problems, as they can help increase the humidity levels.
- ERVs are suitable for homes with high ventilation requirements, such as central heating systems or many people living in the house.
- When using ERV, you do not need to leave your windows open for air circulation in your home, thus enhancing security from burglary.
- No air infiltration when using an ERV! The ERV filters incoming air to prevent dust particles from entering homes.
Cons of ERV
- Expensive to install, as it requires ductwork and extra ventilators.
- Requires installation of a dehumidifier if you live in an area with high humidity levels.
- The air exchange is not always balanced, so the fresh air quality in the house may be compromised over time by the ERV.
- High Maintenance cost. An ERV requires regular maintenance checks and a clean-up.
Pros and Cons of HRV
Before purchasing an HRV, weighing the pros and cons of having one in your home is vital.
Pros of HRV
- HRVs help improve indoor air quality by exchanging stale inside with fresh outside air.
- HRV can also be used for homes with high ventilation requirements, such as central heating systems or many people living in the house.
- HRV is suitable for health reasons because it filters out pollen and dust particles from incoming air. The filtered air is healthy for people suffering from allergies issues.
- HRV recycles heat which can be helpful in cold climates.
- Removes excess humidity and lowers energy bills.
- HRV saves on money over time because it uses the heat from the outgoing air to preheat the incoming fresh air.
Cons of HRV
- High Initial Cost. HRVs can be expensive to install.
- Requires regular maintenance, which can also be costly.
- HRV does not improve humidity levels in the home.
- HRV requires proper ventilation to work correctly, which can be difficult for older homes that lack adequate ventilators or open walls to get fresh air into the house.
In-Depth Comparison of EVR vs. HVR
Apart from functionality, there are many other differences between ERVs and HRVs. Below are some of the in-depth comparisons you can use to make the best choice.
ERV vs. HRV Application/When to Use
When it comes to applications, ERVs are more suited for colder climates where the goal is to recover heat, while HRVs are better for warmer temperatures. ERVs are suitable for homes that have low humidity problems. This is because they can help increase the humidity levels.
On the other hand, HRVs are not as effective at increasing humidity levels, but they are suitable for homes that have high ventilation requirements.
ERV vs. HRV Cost
ERVs are more expensive to purchase and install than HRV as they require ductwork and extra ventilators. The installation cost of an HRV is significantly less than ERVs since it only requires a hole in the wall for ventilation.
ERV vs. HRV Running Cost
The running cost of an ERV is slightly more than that of HRVs. This is because they require dehumidification when the humidity levels are high, which can be costly in energy bills. Additionally, ERVs need to be cleaned and maintained regularly, adding to the overall cost.
ERV vs. HRV Life Expectancy
The life expectancy of an ERV is about 20 years, while HRVs only last for almost 15 years. This is because the filters in ERVs need to be replaced more often than those in HRVs. Additionally, the parts in ERVs are typically made from higher quality materials, which increases their lifespan.
ERV vs. HRV Energy efficiency
When it comes to energy efficiency, ERVs are the clear winner. They can recycle heat, which helps them save on energy bills. HRVs are not as efficient at saving energy and often use more electricity than ERVs.
ERV vs. HRV Cold Climate
ERVs are better suited for colder climates, while HRVs work best in warmer ones. Because they function, ERVs help regulate indoor humidity levels and stop cold drafts from coming into the house. This factor makes them more effective than HRV at regulating temperature and improving comfort levels during winter.
ERV vs. HRV In a Hot, Humid Climate
In a hot and humid climate, HRVs are the way to go. Since they do not regulate humidity levels in the house, there must be an adequate ventilation system to ensure air quality does not get compromised.
ERV vs. HRV Safety
Both ERVs and HRVs are safe to use in the home. However, you must hire a professional to install either system, as they can be tricky to set up correctly.
ERV vs. HRV Allergies
Allergies are less of an issue with HRVs than ERVs. The ERV filters the air in the home, resulting in it coming into contact with dust and other allergens. An HRV lets air flow freely through the house without forcing it to go through any extra filtration systems.
Choosing Between an HRV and an ERV
When choosing between an HRV and an ERV, the best option depends on your specific needs. If you are looking for a system that can regulate humidity levels and save on energy costs, an ERV is the better choice.
If you are more concerned with ventilation requirements and allergies, an HRV would be better. Ultimately, the best decision is to consult with a professional and determine which system would be best for your home.
Below are some factors you should also consider when making your selection;
Regional Climate
ERVs are better suited for colder climates, while HRVs work best in warmer ones. Because of the way they function, ERVs help regulate indoor humidity levels and stop cold drafts from coming into the house during the winter months.
Type of heating system used
If you have a traditional heating system, such as forced-air or radiant heat, an HRV is the best choice. An ERV will be the better option if you have a heat pump or another HVAC system that uses ducts.
Household size
If you have a small household, an HRV is usually sufficient. If you have a large family or many people in the house suffer from allergies, you will need an ERV to ensure adequate ventilation.
Budget
The cost of an ERV is typically more than an HRV. However, ERVs are more efficient and often last longer, so they can end up saving you money in the long run.
Airtightness of the building
ERVs are better suited for buildings that do not have a tight construction since they need to recycle air. HRVs work best in homes with more closed structures because they force air through the house.
Is ERV Better than HRV?
Both ERVs and HRVs have pros, but they are suited for different climates. For colder climate homes that want to save on energy costs, an ERV is a way to go. If you need a ventilation system that does not require electricity, then an HRV would be a better choice for your home.
Additionally, an ERV is the better option for humidity levels. This makes it an excellent choice for homes that want to regulate humidity levels inside their home. If you are concerned about allergies, an HRV would be the better choice for your home.
Do you need an HRV or ERV?
When choosing between an HRV and ERV, it is crucial to consider your specific needs. If your primary requirement is to regulate humidity levels inside your home, an ERV is better.
Will an ERV Remove Humidity?
Yes, just like an HRV, an ERV reduces humidity in your home. This is because it controls the airflow coming into the home and forces any outdoor air to go through a filter before entering your house. However, the humidity taken by the ERV is brought back when the warm air meets the cold air outside.
Should you Run an ERV in the Summer?
An ERV should not be used in the Summer. If you run it, your home will feel very humid and uncomfortable during the year’s warm months. During this time, an HRV is a better option because it does not control humidity levels.
However, if you have an air conditioner making the indoor air cooler and drier, an ERV can help regulate humidity levels. If you have a humidifier, the ERV should not be used during the Summer either as it will cause excess moisture in your home, leading to mold and mildew issues.
Should you Run an ERV in the winter?
An ERV is a good option in the winter when paired with a dehumidifier. This will help maintain humidity levels and regulate indoor temperature so that your home feels comfortable during the cold months of the year.
Conclusion
ERV and HRV systems are great options for the home, and each has its benefits and drawbacks. When deciding which system is best for you, it is essential to consider your specific needs and the climate you live in.
If you are still unsure which system is right for you, consult with a professional to help you make the right decision.