AC~ Leave it on or turn it off?

[mickeyd]

This question has to do with the heater also but I am framing it around the central air conditioning to KISS.

DW and I have had a running "feud" over the efficiency of leaving the AC on during the day when no one is at home, or the person at home does not want the AC on, verses switching the AC off during the day (6AM) and cranking it up around 5PM or so to cool down the place for the evening.

I have not seen any studies on which is a better (cheaper) procedure but if one has been done, I'll bet that someone on this forum has seen the study or has an opinion on "yes or no", "good or bad", "it makes no damn difference what so ever".

[MasterBlaster]

Think about coolling your house as if it's a leaky bucket. There are two issues with the leaky bucket analogy. Filling the bucket and keeping the bucket full. It takes a fair amount of water to fill that bucket initially.

If you want the bucket to be full when you use it you can either:

1) leave the hose on all the time (as needed) to keep it topped off
2) top the bucket off when you need it

Clearly you'll use more water to fill that leaky bucket in 1) above to keep it always topped off.

So, the answer to your questions is... Turn the a/c on only when you need it.

If you want the house to be cool when you come home from work get a timer thrmostat that turns on an hour or so before you get home.

[Texas Proud]

Just buy a set up/ set back thermostat and let it do the work...

But, leaving the air on will cost you money..

[Nords]

What Master Blaster said-- both for heating and for cooling.

But don't tell your spouse that-- tell her that you need to gather data. It's time to buy yourself a Kill-A-Watt!

http://early-retirement.org/forums/i...p?topic=5266.0

http://early-retirement.org/forums/i...8906#msg108906

[mickeyd]

Thanks for the timley responses.

Quote:

Just buy a set up/ set back thermostat and let it do the work...

We have one of those, and it works great, however "off" works a lot better.

OT, the local utility company installed one for free a few years ago (special program, probably government sponsored) with the provision that they could cut off your AC for about 1/2 an hour a day in the summer when the system was being taxed. After 2 years we got to keep it and I don't believe that they can "off/on" us after 2 years.

[Nords]

Quote:

Originally Posted by mickeyd OT, the local utility company installed one for free a few years ago (special program, probably government sponsored) with the provision that they could cut off your AC for about 1/2 a day in the summer when the system was being taxed. After 2 years we got to keep it and I don't believe that they can "off/on" us after 2 years.

HECO uses a load-shedding pager on our water heater.* No state or federal subsidies for this program-- it's a lot cheaper for HECO to pay us $3/month for the privilege of shutting off our water heater than it is for them to build a new electric plant. They promise to restore the power to the heater within the hour.

If they expanded the program to A/C or refrigerators then I'd sign up for that, too!

[mathjak107]

its a tough question as it would really take an engineering survey.The answere really depends on the heat load in the house.As an example the house insulation,the exposure ,window surface area etc all determine how well the house will keep the heat out.If the house takes on heat quickly shutting the ac may be the most efficiant as trying to keep cool a house like that needlessy is a lot of work.Awell engineered home may just take a little input from the ac to just coast along and maintain the temperature.Usually in my experiences a properly sized unit will cool down an area in no time making turning it off the best choice.A unit to small will take way to long to re-cool the area again and so not shutting it down may be the best choice.