Installing a mechanical ventilation system is a great option for overcoming stale, polluted indoor air and keeping your home smelling fresh. Energy recovery ventilators (ERVs) and heat recovery ventilators (HRVs) are both designed to improve indoor air quality and bring fresh air inside a home. Either an HRV or ERV can be a great investment, but it’s important that you know how these mechanical ventilation systems work and understand the differences between the two to help determine which one is best for your home.
How Mechanical Ventilation Works and Why It’s Necessary
Mechanical ventilation systems are something you’ll find fairly often in newly built homes. Older homes often don’t require any sort of ventilation simply because of how they were built and the building materials that were used in their construction. The exterior structure or envelope isn’t sealed all that tightly in most older homes, which means there are plenty of gaps and cracks that allow air to continually flow in and out of the building.
Modern construction methods and building materials are far more advanced, resulting in many newer homes having an envelope that is almost completely sealed and airtight. This is definitely a good thing as a well-sealed envelope makes a home far more energy efficient. The only issue is that a well-sealed envelope traps air inside the building, which can result in higher levels of indoor air pollution and also contribute to higher indoor humidity. This isn’t nearly as big of an issue if you have an older home as older homes are said to “breathe,” which means the polluted air can flow outside and fresh air can seep into the building.
When a home’s exterior envelope is sealed up tightly, the only way for air to flow in and out of the building is to open the windows or doors. Having to keep your windows open obviously isn’t a great solution since it would quickly make the home too hot in the summer and too cold in the winter. Open windows would also allow lots of allergens like pollen to get inside. In humid climates, it would also allow lots of moisture to get into the building and quickly make it too humid. ERV and HRV systems will improve the home’s ventilation without any of these issues.
Both ERV and HRV systems contain two fans that spin in the opposite direction whenever they are running. These systems are typically installed in the attic or basement and connected to a system of supply and return air ducts. One fan draws the air inside the home through all of the return air ducts and then blows the air outside, while the other fan brings fresh air into the building from outside and then circulates it around the home through the supply ducts. This ensures that the building is well-ventilated, which is important for keeping the air quality higher and reducing the concentration of airborne pollution.
How the Heat Transfer Process in an ERV or HRV Works
One thing you need to understand is that ERV and HRV systems don’t just pull air in from outdoors. If they did, they would bring in lots of hot air during the summer or cold air in the winter causing the temperature in the home to quickly increase or decrease. This would obviously be an issue since it would greatly increase the workload on the home’s HVAC system leading to much higher heating and cooling costs.
HRV and ERV systems overcome this issue as they both contain some type of heat exchanger to capture and transfer heat from one air stream to the other. During the hotter parts of the year when the outdoor temperature is higher than the temperature inside the home, the system removes most of the heat from the outdoor air as it’s drawn inside and flows through the ventilator. The heat exchanger works to then transfer this heat to the air being drawn out of the building. This process essentially balances out the temperature so that the fresh air coming inside is cooled down to around the same as the current temperature in the home.
The heat transfer process works oppositely during the cooler months when the outdoor air temperature is colder than the temperature inside the home. In these situations, the ventilation system captures most of the heat from the indoor air before it’s vented outside. This allows the system to then heat the cold outdoor air as it’s being pulled inside the home. By heating or cooling the air coming into the home, ERV and HRV systems will prevent the temperature in your house from fluctuating so that your heating and cooling costs stay lower.
How ERVs Overcome High Humidity Issues
As the name suggests, heat recovery ventilators “recover” heat energy and transfer it between the incoming and outgoing air streams so that the air coming into the home doesn’t make it hotter in the summer or colder in the winter. The difference with energy recovery ventilators is that they also capture moisture in addition to heat. When it’s humid outside, the system will pull moisture out of the air being drawn into the home to prevent the humidity level inside the home from increasing. This means that an ERV will help to control the humidity level in the home throughout the entire year.
An HRV will still help to somewhat control the indoor humidity level, but it will mostly prevent the humidity level in the home from being too high in the winter by drawing moisture out of the building. HRVs aren’t a great option in places with humid summers since they would pull lots of moisture inside. Nonetheless, the fact that Las Vegas tends to be extremely dry throughout the year means this isn’t something you really need to worry about. As such, HRV systems are typically the better option for Vegas homes simply because they tend to cost less than ERV systems.
This isn’t to say that an ERV is a bad choice, but you will be paying more for an extra feature you won’t typically need. Since our climate is so dry and the system will almost never bring much moisture into your home, an HRV will be plenty sufficient to ensure your home is well-ventilated and remains comfortable all year long.
BEST Air Conditioning Plumbing Repair has been providing expert heating, ventilation and air conditioning services to customers throughout the Las Vegas area since 2016. We install a range of mechanical ventilation systems, and our certified HVAC technicians have experience designing and installing ventilation systems for all types and sizes of homes. We also offer professional air quality testing, which is important for knowing what air quality issues are present in your home and how best to overcome them. Our team is also ready to handle all of your air conditioning and heating installation, repair and maintenance needs to ensure you stay comfortable and help you beat the extreme Las Vegas heat. Contact us today for more information on the benefits an HRV or ERV system can bring to your home or if you need any HVAC or plumbing service.