S Florida Home Unoccupied for Summer. What should I set IAQ TSTAT At?

[tmb5107]

Thank you in advance for your responses. Home in Miami is 4,000 sq ft under air. 3 & 4 ton Trane XR15 systems with VS air handlers. Home is fairly tight. We leave for about 2 months every summer. What should I leave the temperature and humidity settings at on the Honeywell IAQ TSTATs in order to prevent mold? Also, I was wondering if it would be worth it to invest in a dehumidifier (portable, probably can't afford whole house now) rather than relying on the AC to control humidity. Would this save much money?

[amd]

If your IAQ is set up to overcool when there's a demand for dehumidification, set the RH to 50% or lower. (A setpoint of 82-87 should do fine)

[mchild]

Thank you in advance for your responses. Home in Miami is 4,000 sq ft under air. 3 & 4 ton Trane XR15 systems with VS air handlers. Home is fairly tight. We leave for about 2 months every summer. What should I leave the temperature and humidity settings at on the Honeywell IAQ TSTATs in order to prevent mold? Also, I was wondering if it would be worth it to invest in a dehumidifier (portable, probably can't afford whole house now) rather than relying on the AC to control humidity. Would this save much money?

As you may know the IAQ has a vacation setting that when you put the system in that mode it will maintain distinct parameters while the home in unoccupied. You will have to set that feature on both stats.

You can go as high as 55% in RH without having a mold problem. If it were my home I would set to 53-54% RH and a temp of around 85.

[teddy bear]

I just parked my FL home for the summer. I turned the A/C "off" and set my whole house ventilating dehumidifier-Ultra-Aire 90 H at 50%RH with the fresh air "off". I have a data logger in the center of the home to monitor temp/%RH. I estimate the cost to condition the 2,500 sqft home to be about $30-$40 per month.
Did a home in Jacksonville that had big mold problems as a new home with a t-stat set at 80^F during a wet year. The next year, the owner installed a dehumdistat set at 50%RH. That year, they had minor mold problem in the closets. The next year, thery installed an Ultra-Aire dehumidifier with a/c set at 80^F and dehu set at 55%RH. No mold problems and the %RH did not exceed 55%RH confirmed by data loggers. Also the owner report $400 less electric for the 6 mos. summe. I have monitored a couple other homes doing the same thing.
I suggest a minimum of a Santa Fe Compact set over the kitchen sink and the t-stat set at +80^F, 50%RH. The Ultimate would be an Ultra-Aire whole house dehu connected to big a/c. Then you could turn off the a/c save some big electical cost. Also you could reduce the a/c operation the rest of the year and be more comfortable with a drier home during the shoulder season.

What ever you decide, I am interested in data logging the results with Hobo data logger that will record the ^F/%RH/^F dew point several times an hour for the summer. We could post the results to show it all worked out. Your results will depend on the amount of rain and wet weather we get in Southern FL. If we have a moderately dry year with only a couple wet days at a time, your a/c set as some suggested, 80^F, 50%RH should do. If we have a wet week at one time, your home will become damp without the dehumidifier during the extended wet spells. Either way, interesting to monitor. I am willing to furnish the data loggers. Email me if interested. Regards TB

[Airmechanical]

leave the temp set at 85 degrees "cooling" setpoint

leave the humidity set at 55%

should be fine



.