A/C strategy

[Sandor]

...Anyway, this is why I started to slightly undersize A/C units in the homes I built around here.

Sandor, You've written this a couple times, and each time I read it I wanted to thank you for sharing it. I now perceive my A/C unit in a completely new light. Where I once saw it as under sized, I now see it as just right. And it does keep the humidity below 50%, too. So anyway, thanks. This will also help me size the next one when this one poops out, likely in a couple more years.

BTW: I keep my A/C thermostat at 79*F from 11 am - 11:45 pm and at 78*F from 11:45 pm - 11 am. It takes about an hour to drive the temp down by this one degree F in my house. And it runs near constant from about 1 pm or 2 pm until 8 pm or 10 pm.

Mo, sorry to keep beating the humidity horse!

 

[BrotherBart]

Sandor:

"Mo, sorry to keep beating the humidity horse!"

Bud-Burbia and the Northern Neck be two whole different humidity animals Bubba. On The Neck if you want a glass of water in the summer just wave the glass in the air.

 

[DavidV]

I don't have any place in my house that I could stick a window unit. They make dehumidifiers that attatch to your central air but after dropping all the cash I did on the central air upgrade I think I'm done. Humidity is definately a beast. Yesterday humidity was 49% inside and today it's 55% . I have no idea what could be making th edifference. I am drywalling the beam we put in so I know there is more water going into the air as it dries. It's been raining for abougt a week. bigger than my concern for inside the house is under the house. I have a crawlspace that is just plain funky. it seems to have become worse since we upgraded the hvac. The lines are insulate but concensation forms on them and drips. This is something I'm gonna have to deal with soon or I think i'm gonna have a problem.

 

[vgrund]

I picked up one of these beasts just to dehumidify my basement. It is a big space. The retail store models didn't cut it but this monster doesn't even break a sweat. I'm pretty sure I could dry fruit with this thing if I wanted to do so. It uses less power than the smaller unit it replaced. It can be standalone (how I'm using it) or ducted.

(broken link removed to http://www.thermastor.com/prod_santafe.htm)

 

[saichele]

After watching this discussion I'm thinking maybe the despot or wally world will have an end of season sale... The central dims the lights when it kicks in, and all I really care about is getting the bedrooms cool enough to sleep.

Steve

 

[Sandor]

I don't have any place in my house that I could stick a window unit. They make dehumidifiers that attatch to your central air but after dropping all the cash I did on the central air upgrade I think I'm done. Humidity is definately a beast. Yesterday humidity was 49% inside and today it's 55% . I have no idea what could be making th edifference. I am drywalling the beam we put in so I know there is more water going into the air as it dries. It's been raining for abougt a week. bigger than my concern for inside the house is under the house. I have a crawlspace that is just plain funky. it seems to have become worse since we upgraded the hvac. The lines are insulate but concensation forms on them and drips. This is something I'm gonna have to deal with soon or I think i'm gonna have a problem.

David, you already have a problem.

I trust you already covered the crawl floor with 6 mil platic? And did a good job?

 

[jjbaer]

We got the backlit honeywell - very nice unit. I'd agree w/Rhonemas that after having the previous generation in our last house, I hated not being able to see anything at night and then turning a light on to check temp, time, or adjust anything. Worth a few bucks more for sure.

The usage feature is also nice to look for on a thermostat - tracks how long it's calling for heat each day, week, and since your last reset of it's counter. A great tool to track how effective your fires are if you're still supplementing w/central heat. And generally very useful to see how effective different programs are at minimizing use.

The one problem with the Honeywell is that it is too smart for it's own good - it tries to adjust it's recovery time based on how long the previous 7 days took to get to your setpoint. That is, instead of saying "turn on the heat at 5PM" you are really telling it "figure out how to make my house 70 degrees at 7PM when I get home." It decides when it should turn on. If you have inconsistent fires that sometimes burn longer than others, then it could be thrown a bit - it's basically trying to automatically adjust seasonally so that in the dead of winter, it would take longer to recover, and would start earlier, but in shoulder seasons, it'll learn that it doesn't really have to start much ahead of 7PM. Fortunately, this more advanced control method can be disabled if needed.

-Colin

Hi,

Just saw your post now but thought I could shed some light on the "too smart" Honeywell thermostat.

I too have one and got up one night (about 2 AM) and heard the furnace on but I also knew that it was programmed to only come on at 6 AM so I thought it was broken...I then read the manual and what it's doing is this: I believe that on my thermostat, there's a sensing device on the back plate of the wall thermostat that senses wall temp......since the wall is denser material than the air, it knows that if it waited till 6AM to raise the house to 70F that while it could easily raise the air temp to 70F, that the walls are cooler and absorb heat and thus you feel "cold" because the walls are cold. You can sense this if you wear a short sleeved shirt and walk in a warm room with cold walls.....i.e., basements come to mind....

So.....let's say the setting is 60F at night and 70F at 6AM. The system will compensate for cold walls by pulsing the system on intermittently for a few minutes to say, raise the air temp to 61, then turn off and let the cold walls absorb this heat and when the house air temp drops again, pulse the furnace again, raise the temp a deg or two, then turn off to let the colder walls absorb the heat. This can continue for several hours until 6AM when the air temp is raised to 70F but by now, the walls are no longer as cold so you feel warmer.

I personally don't like this because if all I want is somewhat warm air for the half hour it takes me to get out of the house, I really don't care about the wall temp being a bit cooler because it's going to get set back again when I leave in 30 minutes.

So, I read the manual some more and on mine there's a small LCD symbol on the front corner of the display indicating that this mode is engaged....so I followed the instructions and turned this feature off...........my gas bill DECREASED!

Bottom line: I want a programmable and "smart" thermostat" but not "too smart"......

Hope this helps!