{"id":3100,"date":"2026-06-19T16:56:08","date_gmt":"2026-06-19T08:56:08","guid":{"rendered":"http:\/\/www.sport-chance.com\/blog\/?p=3100"},"modified":"2026-06-19T16:56:08","modified_gmt":"2026-06-19T08:56:08","slug":"how-do-i-calculate-the-energy-savings-of-an-energy-recovery-ventilator-40e0-89ee76","status":"publish","type":"post","link":"http:\/\/www.sport-chance.com\/blog\/2026\/06\/19\/how-do-i-calculate-the-energy-savings-of-an-energy-recovery-ventilator-40e0-89ee76\/","title":{"rendered":"How do I calculate the energy savings of an Energy Recovery Ventilator?"},"content":{"rendered":"

As a provider of Energy Recovery Ventilators (ERVs), I’m often asked about how to calculate the energy savings these devices can bring. Energy savings are a crucial aspect for both residential and commercial building owners, as they directly impact operational costs and environmental footprints. In this blog post, I’ll walk you through the process of calculating the energy savings of an ERV, providing a step – by – step guide and highlighting some key factors to consider. Energy Recovery Ventilator<\/a><\/p>\n

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Understanding Energy Recovery Ventilators<\/h3>\n

Before delving into the calculation, it’s essential to understand what an ERV is and how it works. An Energy Recovery Ventilator is a mechanical ventilation system that exchanges stale indoor air with fresh outdoor air while recovering the energy from the exhaust air to pre – condition the incoming air. There are two main types of energy recovery: sensible and latent. Sensible energy recovery involves heat transfer, which warms or cools the incoming air, while latent energy recovery deals with moisture transfer, reducing or increasing humidity as needed.<\/p>\n

Step 1: Determine the Ventilation Rate<\/h3>\n

The first step in calculating energy savings is to establish the ventilation rate of the building. This is typically measured in cubic feet per minute (CFM) or cubic meters per hour (m\u00b3\/h). The ventilation rate depends on several factors, including the size of the building, the number of occupants, and the use of the space.<\/p>\n

For residential buildings, the American Society of Heating, Refrigerating and Air – Conditioning Engineers (ASHRAE) recommends a minimum ventilation rate of 0.35 air changes per hour (ACH) or 15 CFM per person, whichever is greater. For commercial buildings, the requirements vary significantly based on the type of business. For example, an office may need 15 – 20 CFM per person, while a restaurant may require 35 – 50 CFM per person due to the presence of cooking and potential odors.<\/p>\n

Let’s assume we are dealing with a 2,000 – square – foot office building with a ceiling height of 8 feet and ten occupants. First, calculate the volume of the space:
\nVolume = Length \u00d7 Width \u00d7 Height
\nVolume = 2000 ft\u00b2\u00d7 8 ft = 16,000 ft\u00b3<\/p>\n

If we use the 15 CFM per person rule, the total ventilation rate (V) would be:
\nV = 15 CFM\/person \u00d7 10 people = 150 CFM<\/p>\n

Step 2: Analyze the Energy Recovery Efficiency<\/h3>\n

The energy recovery efficiency of an ERV is a measure of how effectively it transfers energy between the exhaust and incoming air. It is usually expressed as a percentage. There are two main efficiency ratings: sensible efficiency and total (sensible + latent) efficiency.<\/p>\n

Sensible efficiency (Es) tells you how well the ERV transfers heat. Total efficiency (Et) takes into account both heat and moisture transfer. When calculating energy savings, you need to decide which efficiency rating to use, depending on whether you are mainly concerned with heating\/cooling costs (sensible) or also with humidity control (total).<\/p>\n

Most ERVs on the market have a sensible efficiency ranging from 60% to 80% and a total efficiency between 50% and 70%. Let’s assume our ERV has a sensible efficiency of 70% and a total efficiency of 60%.<\/p>\n

Step 3: Calculate the Energy Demand without an ERV<\/h3>\n

To understand the savings, we first need to calculate the energy required to condition the incoming fresh air without an ERV. This involves calculating the heat or cold load associated with bringing the outdoor air to the indoor temperature and humidity conditions.<\/p>\n

We’ll start with the sensible heat load. The sensible heat load (Qh) to condition the incoming air can be calculated using the formula:
\nQh = 1.08 \u00d7 CFM \u00d7 (Ti – To)
\nwhere:<\/p>\n