Heaters.... what is efficient, any engineers can chime in?

[flyhigh123]

So a topic in a different subforum came up and I asked the questions:

speaking of heaters, what is the efficiency of heaters.

For example, we've mentioned here in regards to wattage, however, what is the efficiency conversion of wattage to actual heat produced? By Brand? By total watts on a single unit?

Is a 300watt the same as 2 150watts? etc... i'm trying to reduce my elec bill any way i can, but also need to keep the tank warm. so i too am debating about switching from 2 300 watts to a 600 watter for example, but is the efficiency the same?

so the question first is, which brands are the most efficient? what is the efficiency of a titanium versus glass if both are the same wattage?

Also is 1 300 watt = to 2 150 watts if both were on at the same time?

We often look at lighting in terms of par versus elec consumed ie MH versus LED, but looking at heaters, i wonder if there is any data for this?

[ReeferVinnEE]

1 watt hour = 3.41214163 btu

A watt is a unit of energy and as far as heating is concerned, it is a unit of heat as well. Im sorry, but as far as wattage and heating, there is no way to make it more efficient since they are one and the same.

If you want to save on heating the tank, insulate it?

[mth1993]

I installed a closed loop off my water heater at a cost of about $130 and it saves me around $90 per month in electricity with no noticeable increase in my gas bill.

[RobbyVonAwesome]

I installed a closed loop off my water heater at a cost of about $130 and it saves me around $90 per month in electricity with no noticeable increase in my gas bill.

Do you mean a traditional whole-house water heater? Can you talk more about this?

Do you run tank water through through the heater or cycle fresh water from the heater through a submerged heat exchanger?

[mussel and hate]

speaking of heaters, what is the efficiency of heaters.

I'm no engineer but heaters are 100% efficient. Think about it what would the residual power from a 90% efficient heater manifest as... heat?

[Mouse]

Is a 300watt the same as 2 150watts? etc...

The use of 2 or more heaters isn't for cost effectiveness, its for redundancy. If you have one heater and it dies/goes on overdrive = major tank issues, now if that same 300W is split between 2 or 3 heaters, the effects of a failure are minimized if not prevented.

[flyhigh123]

i know the redundancy portion. I have a 230 gallon so, normally available are 300 watters. I currently use 2, but feel that i may need a 500 watt and a 300 watt.

Is 1 300 watt = 2 150 watt?

[110galreef]

my understanding is it is basically 100% effecient assuing it is submerged.
To help those electric bills, use submersible pums as much of the enegry they use and heat is then transfered to the water.

Or vice versa of u are running to hot.

[softieatheart]

I installed a closed loop off my water heater at a cost of about $130 and it saves me around $90 per month in electricity with no noticeable increase in my gas bill.

I would like to know more about this. Can you direct me to a website or something, please?

[110galreef]

I installed a closed loop off my water heater at a cost of about $130 and it saves me around $90 per month in electricity with no noticeable increase in my gas bill.

Must be one BIG system to save $90 a month on electricity just on heating....

Man my 250g tank & 40g frag tank only cost me a total of $45/mo to run and that is w/ MH's

[milspec]

I haven't used a heater in my tanks in over 10 years. I can't keep the temp below 80 deg without a chiller. I even switched to LEDs and have an external pump. The lowest my temp gets is around 79.

I still keep a heater in a closet for if something bad happens like the home heating goes out.

[atreis]

Electric resistance heaters are all 100% efficient. You can do better (if you have a large enough tank to justify it) with a heat pump. (How, you ask, can you do better than 100%? Heat pumps extract latent heat in the surrounding medium - water or air, usually air.) Of course, this discussion of electricity leaves out consideration of line and conversion losses during transmission. Gas water heaters are less than 100% efficient - some heat escapes in the flu gas - but the fuel tends to be substantially less expensive than electricity. There are still losses (leaks) during transmission.

[username in use]

Everyone is saying 100% and while I think that they are close, when those coils glow, you are using some electricity to make light, and that will reduce the efficiency some.

[bobby_demay]

im confused...the original question was 1X300 or 2X150 the same. I haven't seen anything regarding this. I would guess though that being watts are a measure of energy then 1X300 or 2X150 would be the same and in my opinion the 2X150 are better for a smaller tank. I believe that oversizing your heater to a certain extent could use less electricity. It takes about 45 minutes for my 500 watt won brothers titanium heater to heat my 275 gal system 2 degrees. I had a 300 watt before and it took it nearly 3 hours and at times i thought it wasn't even heating. So if you do the math on that I have saved myself a small amount of money. If I where you I would get 2X500. Titanium heaters are very reliable and heaters in general are cheap. As far as glass vs titanium in regards to efficiency I wouldn't have the slightest clue however as far as quality I would definitely go with a titanium. I have had nothing but bad luck with glass ones. To me the glass ones are generaly used more for smaller tanks.

[mussel and hate]

im confused...the original question was 1X300 or 2X150 the same.

The question was answered. If an electric heater is 100% efficient the sum total watts=heat regardless of how it's distributed.

Then Mouse explained the advantages of dual heaters:

The use of 2 or more heaters isn't for cost effectiveness, its for redundancy. If you have one heater and it dies/goes on overdrive = major tank issues, now if that same 300W is split between 2 or 3 heaters, the effects of a failure are minimized if not prevented.

On efficiency.

Everyone is saying 100% and while I think that they are close, when those coils glow, you are using some electricity to make light, and that will reduce the efficiency some.

While some energy may be radiated as light(infrared?) when that is absorbed it's converted to heat. Unless your heater is above the waterline in which case there's gonna be trouble.

One might argue that some electrons don't make it to the heater coil from the wall plug due to resistance in the power cord conducter, however those electrons also manifest as heat. All the energy that goes into pumping water in your glass box is transformed through friction from from kinetic energy into... you guessed it heat!

Combustion heaters have less than perfect efficiency. Such is the nature of combustion as you don't always burn all the fuel and some heat is often exhausted.

If I'm mistaken I'm sure an engineer will show up shortly to let me know.

[ReeferVinnEE]

You are right on mussel, er fish242... Im an EE, and it sounds all good to me.

[Whip316]

i would think that 2 heaters would heat better than 1 due to surface area of the heater that is touching the water. also i noticed how and where the heater is mounted helps out alot.

in my one system that i run it constantly at 84 on purpose, its 200g and i have 3x400w heaters in the tank cause its in my basement. if i have the heaters suctioned to the floor or a side i can never get the temp up where i want. once factor is cause i use a reeflow hammerhead pump (5500gph) for massive flow. so i have the heaters suspended in mid water in he sump and i can reach any temp i want now. if they were at the bottom, i can barely break 80.
so i would think 2 x 150 heaters would heat a little more efficiently than 1x300w. plus the redundant fact is a great plus.

[Chris27]

i would think that 2 heaters would heat better than 1 due to surface area of the heater that is touching the water. also i noticed how and where the heater is mounted helps out alot.

in my one system that i run it constantly at 84 on purpose, its 200g and i have 3x400w heaters in the tank cause its in my basement. if i have the heaters suctioned to the floor or a side i can never get the temp up where i want. once factor is cause i use a reeflow hammerhead pump (5500gph) for massive flow. so i have the heaters suspended in mid water in he sump and i can reach any temp i want now. if they were at the bottom, i can barely break 80.
so i would think 2 x 150 heaters would heat a little more efficiently than 1x300w. plus the redundant fact is a great plus.

In your situation, it's likely that the floor that the sump was sitting on was pulling the heat away from the heaters much like a heatsink. By placing the heaters in the middle of the sump, and drawing a great bit of flow around the entire heaters, your using the energy of the heater to directly heat the water, rather then the floor and the water.

[Chris27]

i know the redundancy portion. I have a 230 gallon so, normally available are 300 watters. I currently use 2, but feel that i may need a 500 watt and a 300 watt.

Is 1 300 watt = 2 150 watt?

When it comes to aquarium heaters....yes 2 150W heaters is for all intensive purposes, the same as a single 300 watt.

There will be some slight variances between different models and brands, but it's negligible at best.

[sirreal63]

Another benefit of using 2 smaller heaters is you now have 2 separate points of heat, this will help in efficiency, as it will provide better coverage.

[GeToChKn]

I was just going to post a question asking this as I'm setting up a 125gal tank with a sump for my turtles and wanted to put heaters in the sump. I have a collection of heaters, probably 10 or so from days past varying from 50-100w. Could I just put 3 or 4 of them in the sump instead to allow it to heat. I rather not go buy a $100 heater when I have 10 of them sitting here.

[Chris27]

I was just going to post a question asking this as I'm setting up a 125gal tank with a sump for my turtles and wanted to put heaters in the sump. I have a collection of heaters, probably 10 or so from days past varying from 50-100w. Could I just put 3 or 4 of them in the sump instead to allow it to heat. I rather not go buy a $100 heater when I have 10 of them sitting here.

I wouldn't chance it, heaters are incredibly unreliable, it's never a bad idea to change them out every few years. FWIW, you don't need to spend $100 on a heater, a brand new 250W Eheim Jager should only run you about $30 and it's generally accepted to be the most reliable heater out there.

[GeToChKn]

I wouldn't chance it, heaters are incredibly unreliable, it's never a bad idea to change them out every few years. FWIW, you don't need to spend $100 on a heater, a brand new 250W Eheim Jager should only run you about $30 and it's generally accepted to be the most reliable heater out there.

Thanks. Would that work for a 125gal tank and putting it into my ~25gal sump?

[mussel and hate]

You are right on mussel, er fish242... Im an EE, and it sounds all good to me.

Thanks for the confirmation. I just thought I'd join in the chant;)

I was just going to post a question asking this as I'm setting up a 125gal tank with a sump for my turtles and wanted to put heaters in the sump. I have a collection of heaters, probably 10 or so from days past varying from 50-100w. Could I just put 3 or 4 of them in the sump instead to allow it to heat. I rather not go buy a $100 heater when I have 10 of them sitting here.

Use your existing heaters. If you really feel the need to spend then buy a heater controller for the peace of mind it brings. Just try to ensure that only the heater tube is submerged.

The components that fail most often on heaters are the thermostat, water seal and power cord insulator. I have removed all power cords from contact with water following an insulator failure on a PH than killed my tank :( Plastics harden in a marine environment then they crack.

Lesson learned.

Edit:

I wouldn't chance it, heaters are incredibly unreliable

I must be extraordinarily fortunate. I have a half a dozen heaters several of them over 20 years in continuous service. They all still work perfectly, even the non submersible that I once submerged(and got a shock from).

[ReeferVinnEE]

Since distribution of heat sources has been mentioned...

I remember with planted tanks that the buried cable heating was lower wattage and able to heat a tank better (more evenly) than a higher wattage heater. The situation is more complicated than just that simple comparison. About the real only advantage that we could still take from the cable heaters when applied to reefs would be that heat rises, so putting a heater lower in the tank would mean more time for the heat to stay in the water... in theory.

Our tanks have a couple unique traits to consider. One is that we usually put our equipment and heaters in sumps, so the "heat distribution" of heaters depends more on the sump return pump's flow rate than anything in that case. Second, our reef tanks, sump or main tank, tend to have much higher flow rates. The typical "heat rises" and "breaking up one large heater into multiple smaller ones for better distribution" becomes a mute point when we go from the lower turnover of a freshwater tank (many planted tanks are well below 10x per hour) to a high flow reef aquarium (50x turnover from pumps).

Still, since we put heaters in sumps, and then pump our heated water through pipes that lose that heat we just added, it may be more efficient to keep a heater in the main display than the sump, more so if your sump is in a basement with a long return pipe. Also, some sumps have very low flow rates through them, and then the return piping is usually at the surface of the tank, not the bottom, so unless your return pipe goes right into the flow of a prop/flow pump, you could just be making a hot upper layer... maybe.

With all the other heat sources in our tanks though; pumps and lights (although LED's may make us rely more on our actual heaters for heat) seem to play a larger role than heaters for many of us. I think that conservation of that heat (or removal of it for cooling) plays a bigger role than where and how many heaters we use. An open top aquarium tends to be worlds apart from an enclosed canopy when it comes to heating and cooling. If we add fans to either situation, blowing across the surface water and lights, we remove heat even more. If we add fans and ducting to and from the outside, we can now remove the heat from humidity even faster, or shut it off and retain it. If we insulate our tanks more, sumps, enclose them, use shorter plumbing runs, insulate pipes, have a dedicated fish room with insulated and sealed walls, etc... I think that does waaaay more than any debate on heaters would matter.

On failures... I once swore by the EBO's... until I had almost every one I had fail within a few years a while back. I think there are some varying QC and design issues with some, although with the use of more solid state sensors in the heaters, reliability should greatly improve over the heaters of a decade or so ago. I would still suggest a heating controller though. I think in cases of where a thermostat gets stuck in the "on" position, having something that uses a little backup logic isn't a bad way to avoid reliability problems with any heater.

[sirreal63]

Good points VinnEE, however very few people run with 50x turnover through the sump, more like 5-10x is the norm and many of us even less. The return piping is plastic which has excellent insulative properties and rejects most of the heat that passes through it. If you are running adequate water movement in the aquarium, you will not be creating a hot upper layer. Adding up all of the wattage submerged in the system does have an impact on the heaters usage. Heaters are only on when needed to maintain temp, the pumps in the system are on 24/7 and constantly add heat to the water which reduces the amount of time a heater is working. Multiple smaller wattage heaters are more efficient because of the multiple points of heat, the same way multiple smaller light bulbs will cover an area better than one large bulb. The fans on our systems should not be on 24/7 but only on when a large heat source is on, like lights, when you need to remove excessive heat, this has no impact on the heaters performance, unless you are running the fan when the lights are off.

[mussel and hate]

Multiple smaller wattage heaters are more efficient because of the multiple points of heat, the same way multiple smaller light bulbs will cover an area better than one large bulb.

Actually multiple small heaters are no more efficient than one big heater. I thought we had established this.

Like multiple smaller light bulbs vs one big one of the same total output the only difference is distribution.

Multiple small heaters may heat a volume of water more evenly if they are distributed through said volume, though in a high flow 'reef' system this shouldn't be relevant. If you took 10 x 10W heater coils and placed them in a common tube 12" long would this heater array perform any differently than a single 100W coil in an identical tube? If the 10W heaters have discreet tubes with equal surface area and water flow to the 100w common tube is there any difference? I say no.

My example of course assumes your prize anemone hasn't decided to snuggle up to Mr. 100Watt. I expect you'd note a difference in heat distribution then if not total output.

[sirreal63]

I agree to a point...multiple heaters are more efficient in that they will not have to be on as long to get the whole water volume to the desired temp, the distribution makes the difference. The wattage when running is the same, but the length of time required is different. Or so my experience has been, the engineers may not agree, but how often to engineers ever agree? :D

[A.T.T.R]

If the heaters pull the exact amount of watts listed then yes 2 150s and a 300 are the same


And everything is 100 percent efficient at making heat even light and sound turn to heat ... Eventually

[ReeferVinnEE]

Multiple smaller wattage heaters are more efficient because of the multiple points of heat, the same way multiple smaller light bulbs will cover an area better than one large bulb.

I think I mentioned that this doesn't hold true if we have high flow across the heaters. Lighting is not affected by flow since it is radiant heat, so multiple smaller sources do distribute light better, but our heaters are convection heating. The only time I think multiple smaller heaters would really be more efficient, like cable heating in planted tanks, would be if we have very low water flow, and the heaters are conducting more than convecting.

[DownwardDawg]

Which section of the sump is best for the heater location? Drain/skimmer section, refugium section, or the return pump section?

[mussel and hate]

I agree to a point...multiple heaters are more efficient in that they will not have to be on as long to get the whole water volume to the desired temp, the distribution makes the difference. The wattage when running is the same, but the length of time required is different.

We will assume a temperature of 20C at which one calorie of energy is required to raise the temperature of one gram of water by one degree Celcius. 100 Watt-hours is about 85984.52278589853826311263972485 Calories. So with your 100 Watt-hours you could raise the temperature of about 86Kg of water(86 litres of pure H2O) by one degree C. It doesn't matter how you distribute the heat, the total mass of water will gain the same amount of heat because you are providing a fixed amount of energy(heat) over time.

I suppose you could deliver all the energy in an instant and vaporize some water but that isn't really what we're discussing.

Caveat: I'm not an engineer and I suck at math.

[sirreal63]

We will assume a temperature of 20C at which one calorie of energy is required to raise the temperature of one gram of water by one degree Celcius. 100 Watt-hours is about 85984.52278589853826311263972485 Calories. So with your 100 Watt-hours you could raise the temperature of about 86Kg of water(86 litres of pure H2O) by one degree C. It doesn't matter how you distribute the heat, the total mass of water will gain the same amount of heat because you are providing a fixed amount of energy(heat) over time.

I suppose you could deliver all the energy in an instant and vaporize some water but that isn't really what we're discussing.

Caveat: I'm not an engineer and I suck at math.

Assume nothing...you are not providing the same amount of energy over time. Watch your heater, even before the tank reaches temp, it comes on and goes off in succession. A single source of heat will take longer to reach a homogenous temp than multiple sources, I am sure there is a reason for this, but I too suck at math and am not an engineer and honestly, both heat the water. Where is Bean? lol

Downward Dog...put the heater in a high flow area and forget the science behind it. I used to use the overflow on my old tanks but the new one has a glass_holes overflow, so I put the heater where the overflow enters the sump.

[mussel and hate]

Assume nothing...

We will assume a temperature of 20C
This is to quantify the current energy state of the volume of water(how much heat is in it). Capiche? It is not to say that I am throwing caution to the wind and making wild guesses.

you are not providing the same amount of energy over time.

But this is precisely what I have done for you. I provided the exact amount of energy over time. You can distribute it how you like but the quantity remains the same. I'm not making this up, that's really how it works.

[sirreal63]

I understand the energy involved, but you are not taking into account the variables, surface area of the heaters, water movement, the fact that it is easier to cool a single higher temp than multiple smaller temps with the temperature differential and cooling of the water does begin the instant it is moved from the element, and multiple areas of heat keep the cooling to a somewhat lesser degree. School was a very long time ago, and maybe I am approaching senility but I am not quite there yet. A simple equation cannot quantify all of the dynamics involved, though it would be nice if it worked that way. :D

[GeToChKn]

I put a 150w directly under the bioball water area and a 100w in the compartment the return pump draws from and had to turn them down as it brought the 120gal tank from 72 to 80 overnight, so 2 is certainly enough for me.