What Is a Heat Recovery Ventilator?

December 30, 2019

Heat recovery ventilators have become an important part of maintaining a healthy, energy-efficient, and comfortable home. So, what can a heat recovery ventilator do for a house, and how do they work?

These energy-efficient appliances can help with indoor air quality and energy costs for homes in both cold and warm climates. Here’s what you need to know about how heat recovery ventilators work, and why they might be necessary for your house. 


The Need for Ventilation

Without ventilation in a tightly-sealed home, harmful air particles could be trapped inside the home with you and your family in the air you breathe - everything from dust and pet dander to more dangerous compounds like formaldehyde and radon. Ventilation helps to remove these particles, as well as help control moisture that can lead to mold growth.   

The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) recommends that a home has a minimum ventilation rate or the amount of ventilated air delivered to a living space of 5 cubic feet per minute (cfm) per person. This is to keep a steady supply of fresh breathing air available to the inhabitants of a home to maintain acceptable indoor air quality.  

Historically, the leaks and gaps in older home construction allowed for air to move freely in and out of living spaces, which provided the necessary air changes per hour. This is called natural ventilation. Unfortunately, these older leaky homes also struggle to maintain stable indoor temperatures, meaning inefficient and higher heating and cooling energy costs.

However, as building materials like windows, doors, insulation, and vapor barriers have made homes tighter and “thermally efficient,” a tight home may require mechanical ventilation to reach the correct amount of air changes per hour.  

There are several types of ventilation: natural, spot or localized, and whole-home ventilation. When considering whole-home ventilation, there are four mechanical methods: exhaust (forcing air out), supply (forcing air in), balanced (provide both exhaust and supply without pressurization) and energy recovery or heat recovery systems. 


How a Heat Recovery Ventilator Works

heat recovery ventilator, also known as an HRV unit, combines the need for a supply of fresh air with the demand for energy-saving heat during the colder months. These mechanical ventilation systems exchange the warm, stale air inside your home with fresh outdoor air — but during this process, an HRV uses (or recovers) the heat from your indoor air. 

About 70% and 95% of the heat that is already in your home is transferred to the incoming fresh air through what is called a heat exchanger, recycling the existing heat, and reducing the load on your heating equipment.

Energy Recovery Ventilators

A similar type of mechanical ventilation system is an energy recovery ventilator (ERV). These systems operate almost identically to an HRV but also transfers a certain amount of water vapor along with heat energy. This works particularly well for homes in humid climates as the transfer of the water vapor helps to stabilize humidity levels in the house.

Heat Cost Savings from an HRV

A study done by the Minnesota Sustainable Housing Initiative found that, by design, HRVs and ERVs can reduce the load on your cooling and heating system by between 9% and 12%, making these ventilation systems a great way to save heat energy at home, and increase your indoor air quality simultaneously. With HRV units ranging from $600 - $1,100, excluding installation costs, the typical payback period from heating cost savings is about 6-8 years.


Heat Recovery Ventilator Installation Eligible for PACE

Both HRVs and ERVs eligible for the 100% upfront financing of PACE, as long as the unit has been verified by the Home Ventilating Institute. Through PACE financing, homeowners can lock in their HRV or ERV installation at a fixed, low-interest rate. Then, payments are made as a line item on the property tax bill. 

So, if you are hoping to breathe cleaner air in your home while saving energy, you can finance your heat recovery ventilator costs as a line item on your property taxes! Contact Renew Financial today to find out how you can finance your HRV.