Venstar humidity sensor?

[intellihome]

I was curious as to how a humidity sensor might be incorporated to save money on A/C?

 

I usually set my thermostat to 70 degrees in the summer months. The house is then maintained to 70 degrees regardless of the outside humidity and teperature levels.

 

I know that on a low humidity day 80 degrees feels great! but on a high humidity day 80 degrees can feel like a 100 degrees.

 

Does it sound practical to have a Venstar with a humidity sensor adjust the temperature setpoint based on the humidity level?

 

Is that the purpose of the humidity sensor? Or is it just for a reference?

 

Would an outside humidity sensor work better then one on the inside being the one on the inside is already in a controlled climate?

 

Thanks for any input

[apostolakisl]

I don't think an outside humidity sensor would do you much good. The idea is to make the inside of your house comfortable and both temperature and humidity play into that. You could potentially set your system to run a couple of degrees warmer when the humidity is lower and that might save some money. I am sure outside humidity has a direct effect on inside humidity, but again, the point is inside comfort. I know a lot of people use humidity to control there cooling systems when out of town on Florida homes as the humidity tends to be what causes troubles (mold) not so much the temp.

[intellihome]

I question... does the outside humidity change the inside humidity appreciably?

 

I ask this because...If the house is well insulated and the temp is kept constant, how long does it take for the humidity to "creep" into the house. I think you are probably correct that outside humidity directly affects inside humidity but would it make sense to adjust the inside temp based on the outside humidity.

 

The point I'm looking at is how it feels inside the house. My example is that when the day is beautiful, 85 degrees with low humidity and I walk into my house set at 70 degrees it "feels cold" but when it is a hot sticky humid 85 degree day and I walk into the 70 degree house it "feels refreshing"

 

So on the first situation I could benefit from the low outside humidity and save energy by raising the inside temp to say 72 or 74 degrees.

 

Sorry if I am getting confusing but my questions are actually two.

 

1. The above situation. Does it make sense to adjust climate control based on on humidity? (thank you for your thoughts)

 

2. How can I do it? Can the ISY use the humidity level to create a program? I don't see any selections in the pull downs for the IF statement. Is this something that will be added in future firmware?

[Sub-Routine]

I am not familiar with the thermostat but the Climate module has a Feels Like parameter which is the heat index/wind chill.

 

Rand

[apostolakisl]

I was thinking you could let your home be a couple degrees warmer when the inside humidity is lower. The outside humidity is going to have to affect the inside humidity, but in the end it is only the inside humidity that matters.

 

Some people run fancy set-ups that will calulate how long it will take your home to warm/cool to the desired temp and then use that number to turn the system on at the perfect time to ensure that it hits the correct temp the second you get home from work. Outdoor temp definitely affects that number, humidity probably would but I don't know by how much.

 

I think in the end the outside humidity is a number that you like to know for deciding how to dress, not for deciding how to set up your hvac system.

[jmayzurk]

I question... does the outside humidity change the inside humidity appreciably?

 

I suspect this depends on the house. I added a humidity sensor to my Venstar T1800 (also have a Smarthome V2 thermostat adapter), and since doing so, I have seen discrepancies of more than 50 points (>85% outside, 35% inside). But it really depends on whether you're running heating or air conditioning, how well sealed the house is, etc.

 

The point I'm looking at is how it feels inside the house. My example is that when the day is beautiful, 85 degrees with low humidity and I walk into my house set at 70 degrees it "feels cold" but when it is a hot sticky humid 85 degree day and I walk into the 70 degree house it "feels refreshing"

 

So on the first situation I could benefit from the low outside humidity and save energy by raising the inside temp to say 72 or 74 degrees.

 

This seems like a reasonable theory...and would be easy to test in your own home. The humidity sensor cost me $20 (don't buy it from Smarthome, it's much cheaper elsewhere), so it's an easy and inexpensive experiment.

 

2. How can I do it? Can the ISY use the humidity level to create a program? I don't see any selections in the pull downs for the IF statement. Is this something that will be added in future firmware?

 

There are humidity values between 0 and 100% in the last field of the "Thermostat - Main" condition.

 

-Jeff

[rgs455returns]

My Dad lives in a place that has high humidity. They have a dehumidifier that they use some of the time. You might use the data to control a 2456S3 to turn the device on or off. The dehumidifier are a project to empty and can make a room too cold if it is not needed.

 

 

Just a thought!