Turning off AC for several days in Houston: any dangerous consequences? (Howe: wood floors, house)

[Ghost Town]

I am leaving on vacation in early July for almost 10 days.
I heard that turning AC completely off could be dangerous since it leads to the humidity buildup inside the house and even mold growth. However I do it all the time when leaving for few days, and never had any issues.

Of course I know I can set AC at 80F to keep humidity level lower. But what if the running capacitor dies when I am away, outside fan stops working but compressor keeps pumping continuously for many hours -> freon leaks out and I get major problem with the AC. I had similar situation last summer but fortunately freon didn't leak out (but it was close). Leaving AC compressor running with malfunctioning fan could be dangerous.
Capacitor can die any time and it is a common thing especially during summer.

What do you think, is turning AC off really dangerous from the humidity standpoint or maybe this problem is exaggerated? 10 days forecast for Houston - mostly dry with only few possible showers, temps in mid 90s with 60-70% humidity.
Thanks in advance!

[gwarnecke]

I've heard that a lot of the cheaper materials used in new construction - for example, engineered wood floors - are extremely sensitive to high humidity. One of my colleagues was actually advised by his builder not to set the thermostat above 78 degrees due to risk of the floors buckling (not sure how true this advice is - may have been a CYA move by the builder).

I set my AC to 85 when I'm away. I have an internet-connected thermostat that I can use to check if anything seems odd while I'm away (for example - HVAC running but temperature very high), and shut down the system if needed. I did lose power for nearly two weeks after Harvey, and was worried about the impact of humidity in the house, but there were no ill effects as far as I can tell.

Might not be a bad idea to just proactively change out your capacitor if you're concerned about it - replacements are cheap and it's a 10-minute job. Could change out the fan motor as well.

[hendersj31]

Maybe just get a cheap wifi thermostat for piece of mind. One can be had for under $100.

[marksmu]

Originally Posted by Ghost Town

I am leaving on vacation in early July for almost 10 days.
I heard that turning AC completely off could be dangerous since it leads to the humidity buildup inside the house and even mold growth. However I do it all the time when leaving for few days, and never had any issues.

Of course I know I can set AC at 80F to keep humidity level lower. But what if the running capacitor dies when I am away, outside fan stops working but compressor keeps pumping continuously for many hours -> freon leaks out and I get major problem with the AC. I had similar situation last summer but fortunately freon didn't leak out (but it was close). Leaving AC compressor running with malfunctioning fan could be dangerous.
Capacitor can die any time and it is a common thing especially during summer.

What do you think, is turning AC off really dangerous from the humidity standpoint or maybe this problem is exaggerated? 10 days forecast for Houston - mostly dry with only few possible showers, temps in mid 90s with 60-70% humidity.
Thanks in advance!

No need to worry about the compressor. If the capacitor on the fan dies, the over-temperature protection on the compressor will kick in and shut the unit off. I don't know of any modern compressors that do not have over-heat protection.

Mold grows most in places you can't see it. That is the problem with it. Say between two walls in a bathroom...etc. All it needs is moisture (present in un-air conditioned air) and something to grow on like a cardboard box, a book, drywall, etc.

[Ghost Town]

Thanks everyone for the responses!
Currently I have capacitors all replaced less than a year ago. At this point I am not sure if there is a need for capacitor replacement.
WiFi thermostat? To be honest I hate those things. People lived happier lives in 1960s-70s without those fancy gadgets. I prefer sticking to old school ways whenever possible. Especially I will be traveling oversees and the least thing I want to do during the trip is look for the damn thermostat all the time.
I am not sure if my AC system has overheat protection. Last summer when running capacitor died, the compressor kept pumping for almost a day. I was fortunate that the refrigerant didn't leak, but it was quite possible. My system is from early 2000s

[groovamos]

Why not put a timer type thermostat on there, set it to run from 3 ~ 5 AM at 78 degrees when the heat pumping efficiency is best due to lower outside temperature. That way not only do you save a lot of power, but the system running at the cooler temperatures puts less stress on the components. And the 'running' capacitors, (really starting capacitors) pass decreasing current as the rotors speed up. So if you do the timer thing those capacitors are only dealing with high current once a day, and at their coolest temperature, in the early morning putting less stress on them and not over and over during the heat of the day. The system will dehumidify just as well during those two morning hours.

[analogkid84]

Helpful neighbor to keep an eye on things for you as well?

[Ghost Town]

Originally Posted by groovamos

Why not put a timer type thermostat on there, set it to run from 3 ~ 5 AM at 78 degrees when the heat pumping efficiency is best due to lower outside temperature. That way not only do you save a lot of power, but the system running at the cooler temperatures puts less stress on the components. And the 'running' capacitors, (really starting capacitors) pass decreasing current as the rotors speed up. So if you do the timer thing those capacitors are only dealing with high current once a day, and at their coolest temperature, in the early morning putting less stress on them and not over and over during the heat of the day. The system will dehumidify just as well during those two morning hours.

Thanks, that's a good idea!

[Clothahump]

Two words: programmable thermostat.

[cBach]

I had a friend who had a Vegas vacation house that left the A/C off even in 120 degrees. When you got to the house he stated "crank the A/C and then go to the casino for a few hours". There were no harmful effects from the heat but there is no humidity in Vegas.

I would imagine in Houston you'd probably want to not let the thermostat get above 82 or so. Or if you have a two stage A/C unit just run the one stage dehumidifier.