At What Temp Do You Set Your AC?

[wayupnorth]

It has rained 12 out of the last 14 days and we are now under a flood watch from NOAA. It barely made it to 50 today and has been raining heavily since yesterday and expected to continue thru Thursday. Please send some of the nice sunny warmer weather this way, I am so looking forward to running a/c.

 

[xraytech]

Here the central ac is set at a constant 72 degrees, but if it were up to me it would be at 68 degrees

 

[arbilab]

Wayup.....

I was thinking about a pipeline from north to south so we could split the difference. It's almost twice your temperature here.

 

[wayupnorth]

@arbilab

I wished it was that simple. At least the torrential downpours have stopped here and we have been downgraded from a Flood Warning to a Watch but it is an even 50 degrees now. Its been so long, I have forgot what the sun looks like.

 

[arbilab]

We had record wet from Dec to Apr, then record dry since then. It's probably going to be 10% chance of cloud until October. I like warm but not SCORCH.

 

[spankomatic]

I use the rule of sweat. If I'm sweating it's ON. If I'm not sweating it's OFF. Usually 73 does the trick. Depends on what I'm doing inside too. If I'm just watching t.v. I can stand warmer temp. If I'm cooking in the kitchen I like it cooler. All thermostats are different so I go by how I FEEL at the moment...

 

[retro-man]

Well for the last 3 or 4 days the thermostat is set for 70 degrees in the day and 67 degrees at night. This is running in the heat mode and not a/c. It is supposed to warm up again by saturday. Then we will be back to 73 during the day and 70 at night. Heat is cheaper than a/c here but I would rather have the warmth.
Jon

 

[chromacolor]

72 year round here. My house has little insulation... old windows.. and a poorly vented attic. Funny thing tho.. I had a new furnace and AC installed in 2006, and my utility bills went up, so either the new stuff ain't what it's cracked up to be, or utility costs have skyrocketed since then.
My grandpa was an old HVAC guy, and was one of the first homes in his area to have central AC.. (in the late 40's) It used water, so must have been a swamp cooler? I just remember, he kept it cold in that house.
The advice he always told people with central air, 1) Leave it set at one constant temp. It uses more energy if you turn it off or have too large a fluctuation in settings. 2) Leave fan on "On" not "Auto" as it prevents the air from freezing up, and is better for the unit. Also.. the obvious.. which is try not to block intake/out-take vents.

 

[jerrod6]

My central Ac actually will use more electric if the setting is unchanged from the night to the day.  The trick with it is what your grandpa said and that is not have too large a fluctuation in settings.  I think this is going to vary depending on the construction of each house and how it faces the sun.  (If you have a house that is masonry-brick, stone, plaster walls, or concrete foundations or beams vs houses that are of wall board, vinyl siding and such and also how much solar gain you receive during the day)   If I have too large a setting difference it can take the AC 6 or 7 hours to recover from a day time temp setup setting, so during the day I have a smaller temp difference which translates into a faster recovery period and less run time.  The same holds true for heating; Tstat set very cold at night then it takes into the late morning before the house is warm again.

 

In my case I  find that leaving my fan run constantly causes the indoor humidity to increase during office cycles.  I can feel it, and it is reflected in readout of my  indoor weather station.  You may not notice this if you are running temperatures of 72, but when you get into the 77f to 78f degree range  the rise in humidity makes the house feel uncomfortable.

 

[abcomatic]

I set the air conditioning,(when I need it) at 72-73 and the heat at 67. My house was built in 1897 and so the air doesn't do well upstairs but sure does a great job on the first floor. I have a 1983 GE carry cool and it ends up in my bedroom. One of these days that will have to be replaced but not before it stops running.

 

[spankomatic]

What happens when you leave the fan setting to "ON". When the room reaches the desired temperature the thermostat turns the compressor off. The ice on the evaporator then begins to melt. The moisture from the evaporator then gets blown into the room causing the humidity to rise. When the thermostat fan is set to "AUTO"  the fan and compressor shut off at the same time. The ice on the evaporator melts and drains as it should. If there is too much ice accumulating on the evaporator,blocking the air flow while the compressor is on, there is a problem with the unit. Leaving the fan setting to "ON" is a work around for those who do not want to fix the unit properly. As most know humidity is huge on how you feel in hot weather.  Why blow it in unless your in a ultra dry climate? Photo is normal ice accumulation.

 

[spankomatic]

Iced and blocked evaporator coil. This unit needs to be repaired. Yes running the fan would help melt this. All of the moisture would then be blown into your house causing the humidity to rise.

 

[spankomatic]

Oh yeah... remember to change that air filter often. You don't want this blockage...

 

[DADoES]

 
The evaporator of an air conditioner collects/condenses moisture (like a glass holding an iced drink on a hot/humid day) but it does not (should not) ice- or frost-over like a refrigerator or freezer.  If it does, then there's insufficient airflow.

The blower running continuously will pick up residual moisture that remains after the compressor cycles off and the evaporator temp rises above the dewpoint (thus no longer condensing moisture), carrying it into the room and slightly raising the humidity level.  Auto-fan gives better humidity control.

Auto-fan on my grandmother's Friedrich window unit results in noticeably better humidity control ... and the temperature swing between compressor cut-in and cut-out is wider (to the point of discomfort) on continuous fan with the thermostat anticipator heater disengaged.

Central systems also have an anticipator heater on the thermostat, and per my experience it also seems to disengage on continuous fan.  Well, older thermostats (mercury bulb or bi-metal) had anticipator heaters.  Electronic thermostats anticipate ... electronically.

 

[spankomatic]

Dadeos you make a good point about the air flow factor. I have heard of some people adjusting the fan speed on the unit to reduce noise. I can see where this would make the unit start to build ice...

 

[twintubdexter]

air conditioning and ceiling fans

What is everyone's feeling about using ceiling fans along with air conditioning? I realize you get more even room temperatures but I tend to think blowing warm air down from a high ceiling causes the air to run more frequently. It also circulates warm air from around windows. When I'm on the floor playing with my dogs (and sometimes a guest or two) it seems to be the coolest place in the house.

 

[spankomatic]

True... heat rises.  I do like fans though.. I like the feeling of moving air. When the air is still I feel like I'm in a tin can.

 

[alr2903]

72 summer,  68 winter,  We have 2 central units and 2 window units.  Of course we keep it the way we want it, in the rooms we are actually in. Our old house is fairly tight but also enough interior doors to  manually "Zone", without too much thermostat finagling. alr

 

[sudsmaster]

The master bed/bath in my home was added on back in the 60's or 70's, long before I bought it. It's south facing and has the tallest part of the crawl space. And the heating ducts are bit undersized. As a result it tends to get hotter in summer and colder in winter than the rest of the house. Not a lot, just a few degrees, but noticeable.

I've been considering getting one of the portable A/C units that features a heat pump as well, so it could be used year-round in the master bedroom, and not block up much of a window. So far, however, I haven't found one with a dual hose setup, which would be the most efficient way to go, I think.

 

[spankomatic]

@sudsmaster. My first thought is that the duct work is not undersized but leaking. Very common for duct work this old. Half the air just blowing in the attic or basement not reaching the intended room. Since I'm not one for "work arounds" my first question would be could you have the duct work repaired or resized for the same amount $600.00 as the portable dual hose air conditioner? Might be fun to get an estamate and see how that plays out. Your energy costs would go down and you would not have to deal with the portable unit. My second thought is if you have to go to an additional unit a window unit is a much better performer. Much quieter too. Third thought dual hose units are hard to find. I was unable to find one in any store and ended up having to order one from Amazon. I purchased a Whynter 14,000 btu A/C Heater as a last resort. Window units are not allowed in my apartment complex. The first unit that was sent out was defective and would not turn on. Had to send it back. Big hassel! The replacement unit works fine and does a good job. Hooking up the hoses is a hassle and not the best design. This unit is noisy! I wear head phones to watch t.v.  Consider this in your bedroom when sleeping.  Good luck and keep us posted on how the journey goes...