Air Ventilation - HRV - Knowledge

The Difference Between HRV and ERV Systems


Tags – Difference Between HRV and ERV Systems

Ventilation is a fairly simple concept: it exchanges incoming fresh air and outgoing stale air.

Installing an entire ventilation system not only means fresh air inside, but it also comes with added benefits for your well being and a healthier living or working space. 

To put it simply, ventilation systems can help to reduce the number of indoor pollutants, allergens and contaminants that circulate indoors.

However, they can also help to reduce utility bills and increase a building’s energy efficiency, saving you money in the long run. 

But with different ventilation options available, from HRV and ERV, it can be difficult to decide which one is better for you.

Let’s break this down…

Heat Recovery Ventilation (HRV)

Heat Recovery Ventilation (HRV) is a system that uses the heat from old air to warm up entering new air.

Essentially, this lowers the energy required to bring the outdoor air up to room temperature, therefore saving money on heating costs and bills.

Similar to human breathing, this exchange of air happens in a single location of the building; the HRV core acts like the lungs for your home.

It’s worth noting here, the old and fresh air is never combined during this process. Rather, they move through separate channels.

In regards to efficiency, this usually differs between 55% – 75% but some have been designed up to 93%; of course, these will be more expensive.

Nevertheless, it is still an economic and financially sound investment. 

Energy Recovery Ventilation (ERV)

Energy Recovery Ventilation (ERV) systems are a little more complex than HRV ones, in that they also capture some of the moisture in the air.

For instance, during the colder months, ERV systems work to  move the moisture from exhausted air to the new dry air in order to maintain indoor moisture at a reasonable level; between 40% – 60%

During the summer, the ERV saves the moisture movement and the humidity in the outdoor air is eliminated before it enters the building, therefore preserving energy.

What Can HRVs and ERVs Do?

The two systems are similar in that they both can do the following:

  • Evacuation: they both draw out pollutants from the indoor air
  • Fresh Air: they both rotate the air inside; when a cycle is complete, an equal amount of fresh air is replaced by stale air
  • Filtration: they both include a filter that restricts contaminants, pollen and insects
  • Distribution: they both work in all rooms and can be combined with an existing heating system

The Difference Between ERV and HRV

The main difference between both systems is in their centre unit.

HRV’s heat recovery core’s separating wall is moisture sealed, whereas in an ERV, it absorbs some of the moisture.

In other words, HRV systems only recover heated or cooled air, but ERV systems recover heat and humidity.

Which System to Choose?

The biggest thing to consider when choosing between a HRV and ERV systems is the humidity levels in the building.

However, the following should be taken into account too:

  • Number of occupants: HRV’s will serve the needs of a larger, active household that generates a lot of humidity. On the other hand, the fewer people in the building, the drier the air will be, in which case ERV is the better option.
  • Dimensions: generally speaking, HRV systems are better suited for smaller homes where humidity can quickly accumulate. ERV’s work better in larger spaces where the air tends to be more dry.
  • Airtightness: the better the building is sealed, the less chance there is of humidity escaping, thus a HRV system would be the way to go.
  • Heating System: HRVs work well if you usea non-drying heating system like a boiler. For electric based heaters, these tend to dry the air and so an ERV is preferred.

Rounding Up

Installing a ventilation system brings many benefits, such as:

  • Keeping the air fresh
  • Eliminating allergens, pollutants and contaminants  
  • Retain humidity whilst preventing too much moisture

Both HRV and ERV systems are the most popular choices for heat recovery ventilation, so it really just depends on your individual requirements (i.e. do you need the air to be dry?) when it comes to which one to choose.

Please contact us now to find out more.

In the meantime, take a look at our ventilation systems here.

You may also like:

  1. The Top 4 Benefits of Heat Recovery Ventilation (HRV) Systems
  2. The 6 Different Types of HRV Systems
  3. Benefits of Good Quality Air Ventilation in the Workplace
15th February 2022
Air Ventilation, HRV, Knowledge
Difference Between HRV and ERV Systems
Share This Post
Get Your Free Quote

quotes from happy customers

"HAR installed air conditioning air source heat pump to my living room and bedroom. They done a very professional and neat job. All works fantastic. Thank you. I would highly recommend this company."

David Pearce


"Couldn’t recommend HAR anymore. Very professional bunch of lads. Communication and standard of work was second to none from start to finish. Very happy with the my end product."

Jeff Blackman


Related Posts

How Air Conditioning Is Becoming More Eco Friendly

The Top 4 Benefits of Air Conditioning in Your Car Dealership

Factors that Affect Indoor Air Quality