Attic Ventilation
Attic fans are effective tools to reduce heat and moisture within your attic space. The fans help limit the usage of your HVAC therefore reducing your energy cost in theory. However, the cost to run some traditional overpowered attic fans sometimes negates the savings it has on your HVAC system.
Attic fans all share the same goal, to exchange the air to reduce heat and moisture. In order to achieve this, the air must be moved quickly enough to be effective. If the air fails to be moved, the heat and moisture can easily buildup. This buildup can cause damaging effects to your home.
Therefore, attic fans can be a great option to prevent possible damage to your home and to reduce your energy usage. However, the goal is to reduce the overall energy usage of your home, so there are a few key things to consider when choosing an attic fan.
Key Consideration for Cost and Effectiveness of Attic Fans:
- Energy Efficiency
- Effectiveness of the Fan
- Distributed Airflow
Effectiveness of Attic Fans
Not all attic fans are alike, and the effectiveness of the fan is limited by the type you choose. Therefore, it is important to understand the differences in fan types to help you choose the type that is most advantageous for your space. In a previous blog post, we discussed different fan types and their advantages and disadvantages. The air exchange must happen quickly and effectively to prevent buildup of heat and moisture.
Distributed Airflow
Air needs to be distributed evenly across all areas of an attic to effectively reduce heat and moisture. It is especially important in situations of moisture buildup and condensation. The exhaust fans should not overpower the available intake ventilation. You want to avoid one oversized large attic fan that can pull air from the living space. Multiple energy efficient fans help to balance the airflow. The goal is to pull air through intake points such as soffits and not pull air from the living space.
Attic Fan Energy Efficiency
One of the goals of attic fans is reducing energy usage within the home. The best way to accomplish this is to use energy efficient fans. ATMOX attic fans are energy efficient and can save up to 80% of operational electricity cost compared to traditional electric attic fans with the same output.
Traditional attic fans are often installed in one location within the attic. This type of fan is large and powerful to help move the air. However, there are a few issues with this type of fan. Firstly, this large fan can be actually be too strong and start to pull air from the actual living space. (You don’t want to use your air conditioning to cool your attic.) These fans use a significant amount of electricity and are not energy efficient! Secondly, it does not create a distributed airflow throughout the attic that is needed to reduce heat and moisture buildup. Lastly, these powerful fans tend to be rather noisy.
Cost to Run Attic Fans
When comparing the ATMOX attic fans to a traditional attic fan, you will notice the staggering difference in energy efficiency.
You need to know the actual cost of your electricity as charged by your power company. For illustrative purposes, we will assume the U.S. average cost for electricity at 13.8 cent/kWh. (Data available as of May 2022) The cost of electricity varies from state to state so to find your actual cost you will need to plug in your local rate.
The electricity used when running is measured in watts for most fans. However, the cost of electricity is generally measured in kilowatt-hours (kWh).
In order to calculate your cost, you will need to know how to convert Watts to Kilowatt-Hours. The conversion is made using this formula:
1 Watt (W) = 1,000 Kilowatts (kW)
Comparison of Fans Example
Let’s compare the difference between ATMOX fans and a traditional attic fan.
| ATMOX ATTIC FANS (8 total fans) | TRADITIONAL ATTIC FANS (1 fan) | |
| Total Watts | 1800 CFM = 120 Watts | 1600 CFM = 880 Watts |
| Total kWh | 120 Watts/ 1,000 kW = .12 kWh | 880 Watts/1,000 kW = .88 kWh |
| Cost/Hour | .12 kWh X $0.138 /hour = $0.02/hour | .88kWh X $0.138/hour = $0.12/hour |
| Cost/Day | 2 cents/hour X 24 hours = $0.48/day | 12 cents/hour X 24 hours = $2.88/day |
| Cost/Month | $0.48/day X 30.4 days = $14.59/month | $2.88/day X 30.4 days = $87.55/month |
| Cost/Year | $14.59/month x 12 months = $175.08 | $87.55/month x 12 months = $1050.60 |
Be sure to read that number twice! Yes, if this electric attic fan using average location were to run continuously it would cost over $1000 per year in electricity cost! In general, your attic fans will not run 24 hours per day all year long. Even if you assume the fan ran just 50% of the time your annual cost would be over $500. Remember one of the goals of attic ventilation is to reduce overall electricity usage by giving some assistance to the HVAC system during the summer months.
The cost difference between ATMOX attic fans and this fan is an $875 per year savings! Even if you assume that your attic fan is only running 50% of the time the cost savings is over $400 per year, and that is a significant difference!
Attic Ventilation with ATMOX
ATMOX fans use a sophisticated ATMOX controller to determine the best operational times. Additionally, the sensors are highly accurate and collect data from both inside and outside the attic space. This data is interpreted by the ATMOX controller and operate the fans at the most beneficial times for both moisture and heat reduction.
ATMOX uses multiple energy efficient fans to avoid an oversized noisy attic fan to achieve balanced airflow throughout the attic. Attics may have sections or corners that are not getting consistent air movement. ATMOX uses multiple fans to address all areas of the attic and create even drying throughout the entire attic to avoid neglect in any corner or area of the attic.
As shown in the example, ATMOX fans are energy efficient! You can achieve the goal of heat reduction and moisture control without using a lot of electricity. This will easily save you money over a few years when compared to traditional electric fans.
