HVAC with cool dampness

[Anonymous]

How does AC help? Our house is 70 but 80% RH. aC won’t turn on unless I set it to ice box.

So most people run dehumidifiers all over?

[Anonymous]

When we were getting our air conditioners replaced we learned from the sales people that the design and unit size of the air-conditioning has a lot to do with how cold damp your house feels. If the air-conditioning is too big, it will cool your house quickly, but what remove the dampness so your house will feel cold and wet.

I run my air-conditioning at 70 and my house is not humid.

[Anonymous]

Yes, people have de-humidifiers.

We don't. Last Friday, I had to run the A/C even though it wasn't hot, just because I'd made the mistake of opening the windows to air out the house on a rare (rainy) day without ragweed, to which we're very allergic. We can't open windows in the summer, it's too hot; we can't open windows in the spring and early fall, there's pollen or ragweed. So I usually rush to open the windows when it's raining, because the pollen count is low! I always open the windows in the winter, even briefly when it's freezing, because I love fresh air and it's the only season we don't suffer from allergies.

But that day wasn't the right day, and it turned positively clammy in the house...

[Anonymous]

Dehumidifiers, whether whole-house units integrated into the HVAC ductwork, or individual units, are useful in the D.C. region. They allow the AC to work less hard, while lowering humidity.

[Anonymous]

Anonymous wrote:When we were getting our air conditioners replaced we learned from the sales people that the design and unit size of the air-conditioning has a lot to do with how cold damp your house feels. If the air-conditioning is too big, it will cool your house quickly, but what remove the dampness so your house will feel cold and wet.

I run my air-conditioning at 70 and my house is not humid.

I’m well aware of the oversize issue. But when it’s 70 outside our house doesn’t get that much warmer than 72, but it’s very humid. Generally it takes about 1 hour to drop the zone 1 degree in the summer, unclear if that is right. Our HVAC may be oversized since it’s a heat pump so is also responsible for heating in winter and they have sized the unit for THAT application more than cooling and humidity optimization.

[Anonymous]

We run a dehumidifier regularly when it’s not warm enough the for AC to kick in. The unit is correctly sized for the space. We will be replacing the system soon and plan to get a whole house dehumidifier.

[Anonymous]

From an HVAC contractor: During this stretch of weather even a properly sized system is going to cool to temperature faster than the time it needs to dehumidify. This type of weather is when a inverter system really shines as it can run for long periods at low capacity essentially working solely as a dehumidifier. I don't have inverter systems in my home but run a dehumidifier in my basement as others have suggested.

[Anonymous]

What the prior response said. If you have a single-stage system, it can only cool and dehumidify together. A two-stage or (even better) a variable-stage system can do the dehumidifying separately. You'll get some incidental cooling when the dehumidifier function runs, but a variable speed system is really perfect for our damp but not hot spring and fall days.