Heater alternatives

[JohnGP]

Almost everyone runs heaters that are way too large. Large heaters means more on/off cycles, quicker failure, and worse consequences when they do fail.

The only people who should be running 300+ watt heaters are people who have sumps in unheated spaces.

As above; "huh"?

 

[OrionN]

I have 2 but they are set at 78 and 77. Each 500 W and my tank have 450 gal total.
definately you don’t want too much power in the heater.
Only rarely at night in winter do I see both on at the same time.

 

[92Miata]

As above; "huh"?

What are you confused about? Huh isn't a parseable question.

 

[JohnGP]

What are you confused about? Huh isn't a parseable question.

Pretty much your entire statement; Almost everyone runs heaters that are way too large. Large heaters means more on/off cycles, quicker failure, and worse consequences when they do fail. The only people who should be running 300+ watt heaters are people who have sumps in unheated spaces.

That's a rather broad statement don't you think? How do you know "almost everyone" is using heaters that are too large? As for "only people who should be running 300+ watt heaters are people who have sumps in unheated spaces". What about people who have large tanks? Multiple tanks running off of one sump? So OrionN should be fine with a single 100W heater in his 450g tank?

 

[BZOFIQ]

On a large tank you can tap into your gas water heater and use Titanium heat exchanger to heat up the tank. Search the forum or google it - plenty of discussion on how to achieve it.

This is also much cheaper on a larger tank then to run multiple electric heaters.

 

[piranhaman00]

Pretty much your entire statement; Almost everyone runs heaters that are way too large. Large heaters means more on/off cycles, quicker failure, and worse consequences when they do fail. The only people who should be running 300+ watt heaters are people who have sumps in unheated spaces.

That's a rather broad statement don't you think? How do you know "almost everyone" is using heaters that are too large? As for "only people who should be running 300+ watt heaters are people who have sumps in unheated spaces". What about people who have large tanks? Multiple tanks running off of one sump? So OrionN should be fine with a single 100W heater in his 450g tank?

They are saying to significantly undersized your heater so it basically does not turn off. If it is on at all times it has a less rate of failure. When using 300 watt heaters to heat small tanks the thing turns on and off all day and that will lead to failure quick.

 

[BZOFIQ]

They are saying to significantly undersized your heater so it basically does not turn off. ....

I did that and installed 100W heater as my primary, which is pretty much always on, except when the 'sun' is out.

 

[JohnGP]

I think, or hope, that most of us know that a 300W heater in a small tank is not good, correctly sized heater/s is important but his statement is rather broad IMO. I haven't seen any proof that too small of a heater lasts longer than a properly sized heater/s. Again, just my opinion from my experience.

 

[92Miata]

I think, or hope, that most of us know that a 300W heater in a small tank is not good, correctly sized heater/s is important but his statement is rather broad IMO. I haven't seen any proof that too small of a heater lasts longer than a properly sized heater/s. Again, just my opinion from my experience.

Every switching component is rated in cycles - IE, it only can be triggered so many times on average before it fails. Relays, reed switches, bimetal switches, transistors, all of them. Larger heaters cycle more because they raise temperature quicker.

In a situation where the needed heat load is 50w, running a 60w heater means it may switch on two or three times a day, because it takes a couple hours to raise the temperature. Running a 500w heater means it may turn on and off a dozen+ times a day. Running a 500w heater with a small throttling range (say, .1 degrees) means it may switch on and off a hundred times a day.

There are two failure methods for heaters.
1. They stick on - this is both a high probability event, and a high damage event. The failure method for most of these types of switches is fuse the contact closed.

2. They stick off - this is a low probability event, and a low damage event.

Heaters failing off is lower damage because it takes several hours for a tank to drop a significant amount of temperature because the vast majority of tanks are within 10 degrees of room ambient - and the total amount they can drop is limited by the ambient. Heaters failing on (especially when oversized) has no such safety factor - they can heat very quickly, and the max temp delta is significantly further from the tank's normal temperature.

Because situation 2 is both lower damage and lower probability - you should focus on reducing the chance/impact of situation 1. Large heaters both increase the risk of situation 1 happening (more frequent switching leading to quicker failure) and increase the impact of that situation by raising the rate at which temperature changes, and the peak to which it can rise.

Running a heater that has a 100% duty cycle isn't too small - its properly sized. The risk, and hazard of the most dangerous and typical failure are both reduced to almost zero.

Almost nobody runs properly sized heaters - almost everyone is running too large heaters. (and yes, the 400g people should be running quite a bit - but they're a tiny part of the community). I've seen people on here recommending dual 500w heaters in a 75 gallon tank. That's insanity.

(also, because of the way failure happens in heaters, 2 is almost never better than 1 - unless you have significantly more logging and monitoring than most people).

 

[ca1ore]

Almost everyone runs heaters that are way too large. Large heaters means more on/off cycles, quicker failure, and worse consequences when they do fail.

Don't think that's true …. though I suppose opinions are like ********

The only people who should be running 300+ watt heaters are people who have sumps in unheated spaces.

Or those that run very large tanks LOL.

 

[ca1ore]

I have not found my heaters to be all that prone to failure. I have literally never had a glass stick heater physically break; when they do it is usually a failure of the actual metal coil heating element (so fail = off). I do a few things to 'help' longevity. First, I use primarily EBJ 300 wattage units and do not submerge the head ... so no wires under water. Second, I use both the internal thermostat and an external controller. Third, I calculate heat requirement then divide that number by 2 and run three of that wattage. That way no single fail = off will drop the tank significantly, and no single fail = on will cook it.

 

[92Miata]

I have not found my heaters to be all that prone to failure. I have literally never had a glass stick heater physically break; when they do it is usually a failure of the actual metal coil heating element (so fail = off). I do a few things to 'help' longevity. First, I use primarily EBJ 300 wattage units and do not submerge the head ... so no wires under water. Second, I use both the internal thermostat and an external controller. Third, I calculate heat requirement then divide that number by 2 and run three of that wattage. That way no single fail = off will drop the tank significantly, and no single fail = on will cook it.

Using an external controller is of course a good idea - but it complicates the discussion - because I don't know whether or not the internal thermostats are actually getting triggered (and yes, controller thermostats/relays/etc, fail in the same manner as heater thermostats - they're just typically way higher quality components). If your controller is doing most of the actual switching, then of course your heaters failure mode is going to always appear to be off - them failing on is getting hidden by the controller.


If you're actually calculating load - you're way ahead of most people here. The big point here is that if most people took the time to actually calculate load - they'd find that they're 2-3x where they need to be - and that's dangerous.