Accidentally eliminated temperature swings?

[greatCowOfMoscow]

Bought two new Ehiem Trutemps 100w for my 65 gal. To replace my old ones that were stuck in the on position. And either I’m calibrating them wrong or I have the worst luck because these new ones also won’t shut off. I’m waiting on my heater controller but in the mean time I decided to leave one on.
Hoping it would keep warm enough without overheating the tank. But then I noticed through my in tank thermometer that the temperature hasn’t changed for about 12 hours. It’s reading constantly at 78 degrees. Right where I want it exactly 78. Usually I would have a swing of 1 degree back and fourth throughout the day. Maybe it’s the combination of a single undersized heater and my AC always at 72 that stabilizes it. My question is, is it safe to have that heater on 24/7? Probably bad for my electric bill but might be worth it. Will the heater eventually exhaust itself? Usually heater malfunctions are due to it constantly turning on and off. Mine is just always on.

 

[blaxsun]

Yes, although ideally you want two so that they're both not running 24/7. In terms of lifespan, they'll either go in a few months or be good for like 10 years (really depends on the quality of little fingers on the assembly line...).

 

[Jeffcb]

That's a really good question. A temperature swing of a degree or 2 over a 24 hour period is harmless so I don't see the need for a constant 78 at the expense of so much ac and heater power. Sounds expensive.

 

[greatCowOfMoscow]

That's a really good question. A temperature swing of a degree or 2 over a 24 hour period is harmless so I don't see the need for a constant 78 at the expense of so much ac and heater power. Sounds expensive.

Yeah I would have to agree with you. Not worth it. Except the AC at 72. Alright maybe 73 it’s hot down here and I sleep better. Plus it helps keep the ph up.

 

[KStatefan]

The electricity cost will be almost the same.

 

[regionreef219]

The heater should be just fine in the on position for 24 hours.

All other things equal, you will use less energy keeping the tank at a constant temperature with a heater on 24/7 vs turning a heater on/off and allowing the temperature to fluctuate 2°.

 

[Kershaw]

If I recall correctly the heater staying on is actually better for the heating element then constantly heating up and cooling down.

I think there is even a light bulb that has not turned off in 100 years and it’s because it was left on it was able to last that long.

however if given my luck with heaters it will only last 6 months

 

[ingchr1]

...I think there is even a light bulb that has not turned off in 100 years and it’s because it was left on it was able to last that long...

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[mdb_talon]

I think the risk there is it sounds like you heaters are undersized. If they run 24/7 and keep a perfectly stable 78 then you are at mercy of them operating at peak efficiency. Get some precipitate on them, temp drop in house, extra airflow over tank(evap cooling) then all the sudden it would seem your heaters wont be able to keep up.