Humidifer saving money on A/C?

[mjohnson2981]

I had someone ask me the other day - "I'm house hunting and the house had a dehumidifier running in the house. The current owner says they run it to save money - is this true?"

My answer was that I didn't expect it would save money. I brought up the possibility that 1) there is a good chance that the house has moisture problems (crawlspace) or 2) the A/C system isn't properly sized.

I can see where running a dehumidifier will reduce humidity and help the AC produce more sensible and less latent heat removal. But the dehumidifier will also add heat, which will need to be removed.

I can see where a reduction in humidity can make a warmer temperature feel more comfortable, but that would require using a higher set point on the thermostat to possibly consider it a savings.

Am I thinking correct on this? I don't like giving out bad information.

[miami mike]

They work great when its not real warm out, but the dew-point is high (like when its raining).

Yes, they will save some money by not running the HVAC system to dehumidify when the actual ambient sensible temp is tolerable.

Basically...

[davidadavis]

It depends on the efficiency of the AC system vs the humidifier, as the minimum requirements on humidifiers (at least the stand alone ones) is lower than central air. It also depends on the RH, and if they are venting the humidifier hot air into the home or outside.

[kdean1]

You are referring to a DEHUMIDIFIER rather than a HUMIDIFIER, right?

[kdean1]

It also depends on the RH, and if they are venting the humidifier hot air into the home or outside.

I thought most (if not all) dehumidifiers sent the air from the condenser right back into the house.

[mjohnson2981]

You are referring to a DEHUMIDIFIER rather than a HUMIDIFIER, right?

I screwed the thead title up. Yes a dehumidifier.

[jtrammel]

If the house was vacant and they were only running the dehumidifier instead of the ac to keep the rh down so no mold grows then yes it'll save the seller money.

[teddy bear]

Anytime the outdoor dew point is high and there low/no cooling load, a dehumidifier is more practical to maintain low indoor %RH. The new high efficiency dehumidifiers like the Ultra-Aire remove 4-8 pints of moisture per KWH of electricity. A/c or residential dehus remove 2-3 pints per kwh.
During rainy cool weather, a/c are unable to remove moisture without dramatic over cooling.
Regards TB