# Basic: Rule of Thumb for Newton's Cooling for ACs

1. Aug 23, 2015

### WWGD

Hi, just curious:
Is there a nice rule-of-thumb to apply Newton's cooling to ACs? Specifically, if I know the AC temperature is , say 60 deg. , how long will it take, after I turn off the AC, before thetemperature rises to an unacceptable level of 85 degrees?
Thanks.

2. Aug 23, 2015

### Bystander

If your thumb feels warm, it's probably no longer 60 F. Practically, without knowing anything about thickness of insulation, or ambient temperature, you can say nothing.

3. Aug 23, 2015

### WWGD

Thanks, is there a formula/rule of thumb in function of those two variables?

4. Aug 23, 2015

### Bystander

(Area exposed to ambient temperature times temperature difference between ambient and system) divided by (thickness of insulation times heat capacity of system) in appropriate units.

Large, well insulated systems cool/warm slowly, and small, poorly insulated systems cool/warm quickly.

Are we talking about bait buckets or meat lockers?

5. Aug 23, 2015

### WWGD

Thanks, sort-of in-between . My AC goes down to around 61, I have your average apartment, 2nd floor. I think insulation is average. I will look it up, thanks.

6. Aug 23, 2015

### Bystander

7. Aug 23, 2015

### WWGD

Ah, sorry and thanks again. I have a small window facing sort-of inner garden, around 15' x 15' facing the north side, and it faces another building, i.e., there is a small garden separating my apartment from a 5-story building. No other windows I have 5 stories above me, one below, and and I don't get much direct sunlight. Strangely-enough, the place remained warm in Winter with little, if any heating, but the reverse is not so in Summer, the place is very humid and hot.

8. Aug 23, 2015

### Bystander

Neighbors below, behind, and to either side are elderly?

9. Aug 23, 2015

### WWGD

Ah, sorry again. Neighbors to the right, to the left, top and bottom, but not behind. I don't think are elderly, pretty sure not, but not 100% but how does that make a difference?

10. Aug 23, 2015

### Bystander

There is a tendency for older folks to run their living spaces slightly warmer. Just thought your AC might be having to fight someone's rheumatism.

11. Aug 23, 2015

### WWGD

I see. Thanks for your patience and sorry for my slowness. I will be out for a run for around an hour just in case.