Adjusting Blower Speed for Humidity Control

[wstoftime]

Can someone tell me if it is possible to put a switch on my HVAC system so that I can manually set blower speed? I live in Washington DC and the humidity is terrible. During the heat of summer the AC stays on long enough to dehumidify the house. Come September, when it is in the low 80s, the AC shuts off before the humidity comes down.

What I'd like to do is have a switch so that I can adjust the speed on the fan to slow it down during these slightly cooler September days. I understand that I have a three speed blower, but I'd have to change the wires to adjust the speed. Instead, I'd like to hire a professional to put in a switch that lets me adjust the speed.

Does anyone think this would work?

[BaldLoonie]

It could work. Or could be put on a humidistat. A GOOD pro could rig that up. Of course that only works if you are calling for cooling for longer periods of town. Usually in mild weather, the A/C doesn't run much so even a slower blower won't do too much.

[wraujr]

I live in same area.
3 years ago installed 2-stage AC with variable speed blower. Higher end Trane.
It also has a feature where it "undercools" to remove humidity. While it works, it simply makes the house up to 3 deg. cooler and I notice the lower temp.
This is what you are proposing (i.e. run system longer at lower fan speed)
IMHO, I have come to the conclusion that dehumidification using an AC is a secondary (albeit nice) effect, but that if your primary goal is demudify then you need a
whole house dehumidifier.

What we have experienced late which is endless rain, but low temps, means no calls for AC and therefore no humidity removal with an AC. In the spring and fall (shoulder seasons), humidity removal by AC doesn't work well. You want something that removes humidity without removing heat. But by design and AC always removes heat. The dehumidifer also removes heat but then dumps it right back into the house. Therfore if its 73 for example, the humdifier can run all day without making the house too cold.

[wstoftime]

Thanks for your response.

[54regcab]

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