How do you run your a/c units?

[decodriveboy]

I've got central A/C. House is mid-century, one level, 900+ square feet. Thermostat is set to 82-83 during the daytime and 80 at night. I also keep fans blowing on me.

Power bill starts increasing around May to $90 a month, peaking at around $130 by August, and tapering off afterwards. The rest of the year the electric bill runs between $40-$50 per month, usually, thanks to leaving the windows open.

As hot and humid as it is down here, even indoor temps in the 80's feel very cool.

 

[launderess]

Heat and humidity are not the same thing, and one factors into the other when it comes to comfort.

Many persons can bear dry heat, such as found in desert climates quite well, but simply cannot cope with the high heat and high moisture levels say found in the Southern United States and up the Atlantic coast.

Right now it is a comfortable 75F outside, but the humidity reading is near 95%. A quick walk down the street will show most every home has their AC running, and most are dripping water or one can hear the same sloshing about as the fan slings it against the compressor (some models).

While not an expert, everything one has every learned or heard about air conditoning says yes, run it on high (fan speed) with the thermostat set at a comfortable range when the weather is hot to extremely hot outside. However when the weather is hot and humid, extremely hot and humid or even just warm and humid, to set the fan speed to low; the lesser air flow across the evaporator coils means more moisture will be extracted versus running the unit on high fan speed. While there is a loss of energy efficency, the trade off is feels cooler and more comfortable due to less water in the air.

L

 

[retrochad]

My house has no central heating or A/C however there are refrigerated window units in each room.
The living room has a Carrier 12,000 BTU 240 volt unit; in the kitchen is a 5000 BTU GE; in the workshop/office is a 5000 BTU Hampton Bay, and in the bedroom is an 8000 BTU GE and 5000 BTU Hampton Bay.

Each window unit is set up with a relay kit with low voltage transformer and real thermostat like you'd use for central AC...this way each area gets the precise cooling it needs.
There are timers which shut off the low voltage supply to the relays during the day to save energy. You can see some of the setups on my youtube videos.
On the units themselves the fans are all set at high and cooling on max. The external thermostats/relays do the logic.
There are also fans in each room which run constantly to provide air movement.

After living all of my childhood and teenage years with inadequate heat and no AC I refuse to be uncomfortable even if I have to pay a little more for it! The summertime electric bills for my entire property including house and barn are around $350.00.

 

[toggleswitch2]

It's NOT the heat; it's the humidity.

Hi Jon *WAVES*

I've got a small Cape Cod style house with steam heat and radiators that I was able to add central A/C to via adding ducts with ceiling vents and returns. All three levels of the hosue are cooled, including the finsihed basement. I also have a low return in the basmeent to keep temps consistent from top to bottom of the three levels, and to dehumdify to prevent that musty basement smell.

The temps are set at 77*F int he summer while occupied and 80*F when not, via a programmable LUX brand electronic whole-house thermostat. Methinks the thermostst generates a great deal of internal heat, so my 77*F summer setting results in 75*F room temps.

I has the unit purposely sized a bit small to run longer which reults in better dehumdification. A large through-the wall unit is used for quick cool-downs, when the oven is on and with a house full of people; all times when extra capacity is needed. ALso, I prefer to run the wall unit (no electronics) during storms and power issues. [If something has to blow-out, let it be the supplemetal unit rather than the central unit].

I tend to be at home more in the evenings so my thought process was to have a unit that ran enough at night to dehumidify.

As others have mentioned about their homes, in my house my system come on in April/May and runs till September/October. Opening the windows to allow the in-rush of humidity makes little sense to me. My location is a noisy corner instersection with a nearby commercaal main route. The noise, the dust and locking windows for security every time I want to step out is not for me.

Glenn: It never ceases to amaze me that the masses don't want to understand the laws of physics (and applied science) and how they apply to "real" life. Ever see someone with a climate-control system in the vehicle (the "Temp" dial is a thermostat)? Invariably the dial goes to the min and max settings and allowing the systm to do what it was designed to do (take care of it all automaticaly) doesn't happen.

It took me decades to convince my mother that a thermostat is a temperture activated on-off switch. It does not regulate heat infinitely as the knob of a gas stove regualtes heat and flame-size on a top-burner. In a word, settng the thermostat higher or lower doesn't (usually) get you there any faster.

 

[toggleswitch2]

~Each window unit is set up with a relay kit with low voltage transformer and real thermostat like you'd use for central AC...this way each area gets the precise cooling it needs.

This is a great system. Did it in my apartment. Here, where night are cool, it ensures the unit will start and adequately cool the room.

My A/C was a 10,000 BTU/h unit that had a low enough wattage draw that I was able to use a Honeywell hydronic ("hot-water") heating system circulator control relay.

Transformer and relay built right it. Add power in, add a receptacle for power out, and run a low-votage A/C thermostat to a good location and VOILA! Good temp contol.

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www.pexsupply.com

 

[retro-man]

Hey Toggles!! I have been thinking for years about doing this in my house, with the relays and seperate thermostat. I guess I just never got around to it. You know how that is. I am sure that this is a great way to keep a balanced temperature when the outside air cools at night. I agree I don't need all the yellow pollen that's out there right now in my house. We have gotten showers here the past three days and you can't believe what the sides of the street look like. We are in the peak of it right now, should be gone in 2 weeks or less. I have seen some a/c units where the fan comes on occasionally on very low speed to keep the temp more even. Did not know about the small heater in the bulbs to keep it even also. Very interesting from all contributions on this thread. It seems location location location is the key principal here. Southeast up along the whole east coast very humid and warm and dry and warm in the west and midwest, except along the mississippi right now. My thoughts and prayers go out to all those people there. Well enough rambling, just got home from a funeral from my last uncle on both sides of my family. One aunt left in ca not doing well. When the hell did we get our parents age? lol
Jon

 

[stopmeister72]

I have a 3 1/2 ton packaged unit (10 SEER) out back with a souped up blower motor. Original high speed was 1075 rpm but now it is 1625 rpm. Pretty close to maxing out on the motor amperage but hasn't quit yet. Built a box so it could accomodate a 24x24x12 Hepa filter. The lid is on top so I can prop it open and pull fresh air from outside when I feel like it or when it is cool outside. Keep the house at 70 and in the bedroom have a 5,600 btu Kenmore that I keep at 62 and right now on energy saver. I pulled the sensor bulb away from the coil and have it hanging outside the face of the unit so the bulb doens't get a false temp from being so close to the coil when the fan is not running. I'm on average billing but last summer I used almost $400 a month on electricity. The sad thing is that a few years ago, I blew enough insulation in the attic to add an R30 on top of the 2" of insulation that was up there. Before that, I could run the central a/c, a 5000 btu unit in the kitchen and the one in the bedroom 24/7 and it could not keep the house at 70 during the hottest days.
Now with the insulation, the central a/c only runs around 13 hours a day. Sad thing is that I have seen no savings in $$$ because the electric rates have gone up soo much, but it does stay cool now.
Got a question - on packaged units, can't seem to find them with a higer SEER than around 16 however you can get higher on split systems. Is this becuase since it is one whole unit, the blower motor, compressor, and condenser motors are all added to calucate the SEER? On a split system, do they only factor in the condensor and compressor motor in the SEER or do they factor the matching furnace motor in on it as well?
Here is an interesting article on SEER and EER. Looks like not all SEER ratings are the same on units when compareing to the EER. I think it would be most important to buy a unit with a higher EER not necessarily a higher SEER. What do you think?

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www.energy.ca.gov

 

[toggleswitch2]

~The lid is on top so I can prop it open and pull fresh air from outside when I feel like it or when it is cool outside.

1- This makes more sense knowing you have a packaged unit (i.e. entirely outdoors with ducts going into the house).

~on packaged units, can't seem to find them with a higher SEER than around 16.

2a- Split-sytem fan motor probably NOT factored it, therby raising their rating.

2b- Many split systems can have (physically) larger coils/units than a packaged unit. This is usually a way to gain efficiency.

2c- Heat pumps have their defros cycle factored in, which kills efficieny ratings. [ie.e its not fair/reasoanble to compare A/C *ONLY* systems; ratings to heat pumps). Electric resistance coils are energized during the defrosty mode/cycle which is essentially *cooling* mode (transfer heat from in the hosue to out, while stopping the "condenser" (outdoor unit when cooling) fan motor.

 

[river_realtor]

the central a/c runs 13 hours a day

mine runs maybe 4 or 5 at most... its a 2005 carrier system.... 1700 sq ft house .. bills at $85 monthly

my last house had an 86 11 qt trash can sized carrier and it ran 18 hours a day, had $150+ bills monthly.. 1000 sq ft

same area and minimal rate hikes