You might think that mild fall days would be the easiest for your home’s HVAC system. And in some ways, you’d be right. Milder temperatures mean that your home’s HVAC probably isn’t running very much. That’s actually the challenge.
When your HVAC system isn’t running, the air in your home isn’t circulating. Here in the Tennessee Valley, our autumn days can often be rainy and humid rather than dry and crisp like in other parts of the country. Add allergy-inducing fall pollen like ragweed and you’ve got the potential for some serious indoor air quality issues.
Let’s take a look at the HVAC challenges we get with mild fall weather. Here are ways to deal with them to help keep your home comfortable all year long.
See Also: Autumn Energy Saving Tips
When the Air Isn’t Moving
Is your HVAC system is only running for a few minutes every hour—or not at all—for days at a time? Then the air in your home can begin to stagnate. You may find hot or cool pockets forming. This could be where west-facing windows are getting warmed by the afternoon sun. That’s because the air isn’t getting circulated and mixed by the HVAC system.
Additionally, if the air isn’t moving through the system, then it’s not passing through the air filter. Indoor air pollutants like pet dander, dust, and pollen can build up because they’re not getting regularly filtered out.
On those overcast and rainy autumn days, humidity can leach into your home. In warmer weather, your air conditioner removes humidity from the air while cooling it. In the fall there’s nothing to remove that humidity. Your air conditioner is not running as much. This can lead to your home’s air feeling clammy and even increase the chances for mold.
What About Opening Windows?
One popular solution for ventilation and comfort in the fall is opening up some windows. On a beautiful autumn day, it can feel wonderful to have a fresh breeze blowing through your home. Generally, opening windows can be a good way to improve ventilation and remove some indoor air pollutants. This is great particularly for chemical gases like VOCs, from your home.
However, opening windows can have some downsides too. Obviously if it’s raining or damp outside, opening windows can just make your humidity problems worse. This can potentially lead to water damage.
On dry days, open windows can allow allergy-inducing fall pollen to blow right into your home along with that fresh breeze. If anyone in your household suffers from fall allergies, opening a window may cause a lot more discomfort than it relieves.
Dead leaves in your yard can be a breeding farm for mold, especially if those leaves are damp. Again, opening a window can allow the mold spores into your home, where they can cause allergy and asthma symptoms or even settle into damp spots and begin to grow.
See Also: From Leaving Your Windows Open to Turning on Your Furnace, Autumn is Just Around the Corner
Solutions for Fall’s HVAC Challenges
So what can you do to help keep your home’s air fresh, clean, and comfortable during mild fall temperatures? First, you may want to consider switching the fan setting from “AUTO” to “ON” for at least an hour or two every day.
While switched to ON, the fan will run continuously, circulating the air through your home even when the heating or cooling isn’t engaged. This can help prevent the creation of hot or cold pockets by moving and mixing the air.
Even more importantly, running the fan will cause air to circulate through the intake filter. That way, the pollen, dander, and mold spores in your home’s air can be filtered out. Just be sure that you’re changing the filter regularly so it can effectively clean your air without reducing airflow. Once a month is best!
If humidity is a big problem in your home, you might want to consider adding a whole-house dehumidifier. These dehumidifiers work independently from your air conditioner, so they’ll keep your home’s humidity in the ideal range of 30-50% even during mild weather when the AC isn’t running.
Raking and removing the fallen leaves in your yard can help reduce your home’s exposure to mold. Avoid opening windows in the early morning when pollen counts are highest.
If you want additional ventilation without the risk of letting in pollen and mold, consider a mechanical ventilation system. An Energy Recovery Ventilatory (ERV) will draw fresh outside air into your home while filtering out pollen and other particles that could pollute your indoor air.
Plus, during the warmer and colder times of the year, the ERV will continue to ventilate without wasting the energy you’re using to condition the air in your home. That can be particularly helpful for reducing the build-up of indoor air pollutants when our homes are shut up tight in the summer and winter.
See Also: Simple Upgrades to Your HVAC for Autumn
Keep the Air Moving with a High-Efficiency System
Finally, consider investing in upgrading your home’s HVAC to a high-efficiency variable-capacity system. Unlike standard HVAC systems that simply turn on or off, high-efficiency systems with variable-speed compressors, modulating gas burners, and ECM fan motors can adjust to run at a very low capacity in mild weather.
This means that instead of shutting down completely most of the time when the weather is mild, these systems can continue running, just at a much lower, energy-saving speed. That can keep your air moving and your humidity under control while maintaining a constant, comfortable temperature. And due to the ultra-high efficiency of these systems, they can significantly reduce your energy bills all year long.