A technician installs vents for an ERV system in a home's attic

During winter, the last thing you want to do is crack a window open. Fresh air may not seem as important as warmth, but lack of it can compromise indoor air quality. This is where energy recovery ventilator systems (ERVs) can prove invaluable.

Introducing this system in your home will ensure you and your family breathe fresh air without losing precious warm air from your HVAC. Think of it like opening a window in the middle of winter without getting chilly. 

How Energy Recovery Ventilator Systems Work

ERVs use two fans which create two independent air streams. The first one pulls fresh outdoor air into your home, and the second expels stagnant and polluted indoor air outside. As the airstreams go through the ERV, heat and moisture are transferred inside during winter and out during summer. 

Specific Mechanisms of ERVs

When summer rolls around, humidity levels can spike to pretty high levels.

Some people opt for heavy-duty dehumidifiers to remove excess moisture from indoor air. Others also add a ventilator to this appliance or try other things. The blower pulls in fresh air, which is then dehumidified and filtered before entering the home. 

This phenomenon is known as ‘positive pressure’ since it pushes fresh air into a house. In most homes, polluted air exits on its own as it makes way for clean air. Positive pressure is excellent for homes that are not airtight or don’t have energy-efficient improvements. 

The balanced ventilation an ERV system can give is different in comparison—the equipment automatically introduces and removes air simultaneously.

It’s called ‘balanced’ ventilation since the system exchanges equal stale and fresh air. These systems are built tight enough to prevent air from escaping, which spells good news for your energy bills. 

How Air Tightness Is Measured

The best way to discover whether your home needs an ERV ventilation system is through a professional home energy audit.

A certified advisor will use a blower door test to determine this. A blower door test involves a giant fan used to blow air out of the house to determine how airtight it is.

A pressure monitoring device in the foreground attached the rest of the blower door test system behind it
A set-up blower door test machine.

When To Install an ERV

Air changes per hour (ACH) indicates the number of times internal and external air are exchanged through cracks and other openings. A low ACH suggests your house is relatively airtight. In contrast, a drafty home would be considered higher than 7-10 or so. As a general rule of thumb, less than 3 ACH is low enough to require an ERV. 

Importance of Air Ventilation 

With time, emissions from appliances and the carbon dioxide we expel can build up to dangerous levels in your home. If those emissions aren’t vented out timely, you and your family can suffer health complications such as respiratory illnesses.

Just take a look at your window panes. If you see water condensing and dripping down the glass during the winter, your home is not vented correctly.

While options such as a bathroom fan and a range hood fan can work, they have their limits.

An ERV exchange component and vents on a home's exterior.

Whole-house ventilation systems such as an ERV can recover thermal energy in exhausted air, preheating fresh air in winter and pre-cooling it in summer. So if your energy bills are sky-high, an ERV can reduce them significantly. 

Top Reasons You Should Get an ERV

Here are some of the best benefits that an ERV can provide when it comes to your wellness and health:

Enhanced Indoor Air Quality 

As mentioned before, an ERV flushes stale air out of your home and brings in fresh air. However, most people don’t know that it also flushes pollutants with the former.

Things expelled include common allergens such as pollen, dust, dander before they can get into your home. This process improves indoor air quality, leading to better sleep, reduced respiratory issues, and enhanced focus. 

Improved HVAC Efficiency 

If your energy bills are higher than they have ever been, chances are your HVAC system is working harder than it should. Plus, if you have an old system and find yourself opening windows and doors frequently for fresh air, you are losing a lot of precious heated and cool air, which is just a waste.

An energy recovery ventilator system will prevent you from throwing your money out the window. It can ventilate your home efficiently without the need to open a window.

Plus, it will do so with minimal energy loss. This way, your home will be more comfortable, indoor air more breathable, and your utility bills will also diminish. 

Consistent Safe Moisture Levels

High humidity levels can ruin your rugs, wallpaper, ceilings, and drywall. Significant moisture can also lead to mold growth, triggering deadly allergic reactions.

Unlike HVAC and systems that only heat and cool air, an ERV maintains moisture levels by transferring heat between two air streams and expelling the moisture they contain.

The system takes moisture from the air stream that has more than the other and transfers it to the latter. This process removes most of the humidity out of your home during summer. 

However, ERVs should not be confused with dehumidifiers—they only maintain healthy moisture levels indoors. Install a whole-home dehumidifier if you want to reduce indoor moisture levels and ventilate moist air out of your home at the same time. 

Prevention of Nasty Odors 

ERVs also remove airborne contaminants and pollutants by filtering the air as it comes into your home, including odor from cooking and pets, human waste, and other sources that can cause diseases and make living indoors a nightmare. 

Easy Maintenance

Your ERV maintenance guy can also look over and clean your ERV system during routine maintenance. All you need to do is ensure the filter is changed every couple of months or so. Besides that, these systems require little to no intervention to functional well. 

Controlled Ventilation in Your Home 

You lose a lot of precious conditioned air from your home when you crack open a window. That negative effect is compounded if it is extremely hot or cold outside.

ERVs prevent this kind of energy loss by giving you control over the amount of ventilation your home receives. You can increase or reduce it as needed for the perfect internal temperature and humidity levels.

Unlike a positive pressure system such as an HVAC, an ERV operates independently so you can determine if it is exchanging the right amount of air or not. 

The Comfort of Your Home

We can now safely say that ERVs improve the comfort level of your home, which can go a long way in ensuring it is clean, healthy, and a pleasant place to be. 

There are two types of ERVs you can investigate. One works independently of your HVAC system, and the other can be attached to it and work with it.

If you opt for the latter, hire a professional contractor to integrate the ERV system into your forced-air system. Here are some of the things they ensure during installation:

  • The fresh air comes from an area where it can circulate, meaning it should be away from your driveway, furnace flue, and laundry vents.
  • The fan for the primary system is on at all times. Otherwise, fresh air from your ERV will not be able to circulate correctly. 
  • The ventilated air has access to the return duct of your HVAC system so it can circulate through the ductwork. 
  • Point source exhaust fans are installed in all of the bathrooms in the home to expel odors. 

If you have the space for ductwork, the ERV system can be installed right into your forced-air system. It should be in such a way as to remove air from bathrooms and introduce fresh air into rooms that have high traffic, such as your living room. If installed correctly, the ERV will not compromise your HVAC system and should enhance its efficiency. 

An independent ERV system will also be able to remove polluted air from your bathroom through ductwork. However, it will push fresh air into the return plenum whether the blower fan is working or not. 

Bottom Line

If your bills increase by the month and your home is unbearable during the summer and winter, invest in an ERV system. It will end up paying for itself in the long run.

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