Science and the Role of Humidity in Your Home's AC

Humidity is arguably one of the worst aspects of hot weather in Radford, VA. Unsurprisingly, high humidity levels drive people to turn on their cooling systems. What may surprise you is how much humidity affects the overall performance of your air conditioner. Here are five things you need to know about the role of humidity in your AC.

1. Latent Heat Load

The idea of steamy weather is closer to literal than you might guess. Humidity produces a latent heat load in your home's air. Suppose the temperature is 76 degrees Fahrenheit in your living room, and you want to get it down to something like 72 degrees. The job of cooling isn't as simple as getting the air molecules from 76 to 72 degrees. When the humidity is higher, the cooling process requires more energy to achieve the same 4-degree reduction.

Why is that the case? Latent heat sits in the water vapor — the steamy air — in the room. You aren't just cooling the air. You are also cooling the water vapor. The difference between cooling the same air at 30% humidity or 90% humidity could be threefold in extreme cases.

2. Energy Efficiency and Dehumidification

One of the main reasons that HVAC systems typically operate as dehumidifiers is that your home's system will have an easier time cooling drier air. The more humidity the HVAC system removes and keeps out of the air, the less energy is needed to cool it. Consequently, the latent heat load is an energy efficiency issue. If the AC keeps the house drier, it will also use less electricity continuing to cool the house.

3. Equipment Service Lifetime

Work is work, and that applies even when you're thinking scientifically about how your AC handles humidity. Whether the system has to work harder to cool steamy air or dehumidify it, the components still have to do the work. This means the entire AC system has to go through cycles to get the job done.

With an increase in cycles comes a corresponding increase in mechanical wear. The condenser has to run more. The fans in the ducts have to run more. The system activates the dampers more. Everything has to work more to achieve the same result. For that reason, you want the system to run as efficiently as possible to minimize wear and tear. Over the long run, improved efficiency should maximize the service lifetime of the equipment.

4. Indoor Air Quality

Modern HVAC systems do more than heat and cool the air. They also serve as the central systems for controlling indoor air quality in many homes. Optimally, the outdoor air goes through a controlled system of filters and ducts. This ensures that clean and comfortable air comes out of the registers in your house whenever the system runs.

Filtration is only part of the equation, though. Mold likes to grow in environments with humidity levels above 60%, so keeping the level of mold down depends on keeping the humidity below that threshold.

Notably, this means monitoring multiple locations in the house with sensors. If you take a reading in one zone, it may be acceptable. Depending on that single reading is asking for trouble because rooms further from the thermostat's sensors might have higher humidity levels. This only gets worse in spots like the insides of walls, the basement, and the attic. In other words, the conditions could be fine for mold growth even when you think the problem is under control.

5. Personal Comfort

Finally, humidity affects your comfort in your house. The house will feel stickier, and you'll have a harder time physically recovering when you come inside on a hot day. Worse, you may set the thermostat lower to try to get relief, and that leads to inefficiency and system wear. A well-designed cooling system should keep the humidity low so you'll have maximum comfort.

New River Heating & Air has been in business since 1986. Our team is proud to serve residents of the New River Valley. We handle an array of heating and cooling projects in residential and commercial settings, including installations, repairs, and maintenance. You can check the specials on our website. We also offer financing options for qualified customers.

Call New River Heating & Air today to ask a member of our team about your home's heating and cooling needs.

Naomi Pluchel