The thing Pittsburgh homeowners do not realize

The biggest thing that does not get talked about with air quality in Pittsburgh is humidity. It gets crazy humid here. We obsess over the temperature on the thermostat, but the moisture in the air matters just as much, and most people have no idea there is even a solution for it.

If you have ever checked into a beach rental in Florida and the cushions felt wet and clammy, or you have climbed into bed here in Pittsburgh in July and the sheets felt damp, that is high humidity at a regulated temperature. It is not a good feeling, and it is more common in our homes than people think.

Sensible vs latent heat, in plain English

Air conditioners remove two kinds of heat. Understanding the difference is the whole key here:

• Sensible heat is what you can feel, the actual temperature. That is the part your thermostat reads.
• Latent heat is what you cannot feel directly, the moisture in the air. Removing latent heat means pulling humidity out.

Over the years, equipment has shifted to handle more sensible load and less latent load. For a dry climate like Arizona, or a place like San Diego that is mostly cool and just occasionally needs the edge taken off, that is fine. But in a humid climate, that shift means we cool the air down without dehumidifying it well enough. The temperature drops, but the moisture stays too high.

Why 70 percent humidity at 70 degrees is a problem

Picture a typical Pittsburgh summer day, 90 degrees and 90 percent humidity outside. You set your thermostat to 70 and the temperature is fine, but the relative humidity inside is sitting at 70 percent. Remember, we are really talking about RH, relative humidity, which is the amount of moisture in the air relative to how much the air can hold. Seventy percent at 70 degrees is a lot of moisture, and it causes real problems:

• The air feels thick, and for people with asthma it can be genuinely hard to breathe.
• Doors stick, furniture swells, and instruments fall out of tune.
• That cold, clammy, damp feeling settles over the whole house.
• Worst of all, 70 percent is a great breeding ground for mold. The amount of mold that can grow at that level is no joke, and it is rough on anyone with mold allergies.

The fix: a whole-home dehumidifier

The answer in these situations is a whole-home dehumidifier that pulls that latent moisture out of the air. We want to get you down to around 50 percent relative humidity. At 70 degrees and 50 percent RH, you will be comfortable, and here is the bonus, you will actually feel cooler. A lot of folks can even bump the thermostat up to 72 at 50 percent humidity and feel more comfortable than they did at 70.

There is a neat side benefit, too. Say your home gets too warm in summer but your AC is running as well as it can, it is just a little undersized. By adding a whole-home dehumidifier in the basement, we can make the home feel noticeably more comfortable with the same air conditioner. It is a nice, almost free add-on in terms of comfort.

Why not just buy a portable dehumidifier?

I caution people hard on this. The number of consumer report warnings on portable dehumidifiers is terrifying. We hear about them causing home fires all the time. They are also super energy hungry, inefficient, and they just cannot keep up with the amount of moisture removal a home really needs.

A whole-home Aprilaire costs a little more up front, but they are made in the United States, they are high quality, and they are safe to run year-round without worry. For real, reliable moisture control, that is the way to go. If you want to talk through your whole home’s air, start with our indoor air quality page.