Until I get a dedicated dehumidifier for my house, I thought I'll start off with using the AC unit to keep the humidity in check, to some extent. So, I set up a rule in RM to force the AC to cool even if the temperature isn't high (but the humidity is) by lowering the cooling setpoint. Then, once the humidity is at a relatively lower level, I'd like the setpoint to go back to what's set per the program.
The rule works most of the time. But, at times I get an error as in the screenshot from logs. Any idea what could be causing this and how can I fix it?
I can't really find anything in your rule that should throw that error, unless it is caused by the ecobee cloud not being available temporarily.
However, I have a couple comments:
It seems like your house gets really humid (a RH of 75% at any temperature can't be good for you).
Your rule is likely to promote compressor short-cycling, which isn't good for your AC compressor. I would suggest decreasing the temperature by more than 1 degree (say 2-3 degrees), and decrease the frequency of your trigger to every 20-30 minutes.
Yes, I agree. I live in Houston and it does get rather humid here. I moved into this new house barely 2 months ago and it is still under warranty. The AC company is supposed to come and take a look to check for any leaks, other issues, etc. Any level above 50ish isn't good.
Agreed. What I have also set on Ecobee is what they call "AC overcool max" that causes the AC to cool an additional 1.5F to decrease the humidity. So, that's a total of about 2.5-3F. I just wanted to get started with the rule and change the parameters for fine-tuning as needed. I'll keep your feedback in mind though.
I live in New Orleans - also very humid. Rather than control my house by humidity alone, I control the thermostat based on the indoor dew-point. This has worked very well for the last ~1 year. My compressor cycles are long (~20+ minutes), and indoor comfort has been really good.
That is one option. And it will definitely increase comfort. But they should not be necessary if your AC (or heat-pump) is sized correctly.
Another option is a variable speed AC with a variable speed air-handler. When they both run at low RPM, they will dehumidify really well while maintaining a reasonable temperature.
A third option is a dual-stage AC with a variable speed air-handler. This was the choice I made, and I'm satisfied with it. But I was in a position where my existing AC was ~12 years old (and an R-22 unit), and the air-handler was almost 20 years old. So I had to replace them any way!
I'd have liked it if that's what I had. But I seem to have only option 1 for me given the builder put a single-stage AC and air-handler (without variable speed). Of course, given this is a new house, I can't get rid of the AC unit that's barely a few months old. So, I'll find out on Friday what the AC guy has to tell me.
Also, as a suggestion, can the AC guy slow down the indoor blower by using a slower tap on the blower motor? I had done that for a few years before I replaced everything. It does help.
So, the house is approx. 3700 sqft. (2 story). As for the AC units, I'll have to double check by going out taking a look at the label, but I believe I have a 4 ton unit for downstairs and 2 ton unit for upstairs. Again, I need to verify that.
Thanks for the suggestion: he's supposed to visit Friday so I'll ask and see if that's an option at all.
As a first approximation, that sizing seems appropriate, so your systems are unlikely to be short cycling. There is something else that is raising your indoor humidity (maybe duct leakage?).
Yeah I would think that a reputed builder like mine wouldn't go that far saving money and give me a unit that's useless for cooling the house. I did have the house inspected by a 3rd party inspector walking around with an IR heat scanner/imaging unit and he didn't catch any leakage issues; at least, not in the living space. I understand it is humid outside, but there's no reason that my indoor humidity should be that high given I keep the AC unit set to cool to about 72-74F.
This recent thread might be of interest to you. It was started by someone else from Texas (@Hal3) whose indoor humidity was crazy high.
In this case, I think the major culprit turned out to be a poorly positioned thermostat. Although I do believe that lowering blower speeds also helped.
Geez, yeah it definitely sounds like something is wrong. I also live in Houston, in a house almost the same size, also two story, also with a 4-ton and a 2-ton AC unit. My indoor humidity has never gotten over 60% in the main downstairs living area in the past year:
Bathrooms are a different story, as they can get quite high (80-90%) while taking a shower and generally have a higher humidity throughout the day. So @aaiyar might be right: it may just be placed poorly.
