Heating A Fish Room

[Rorie]

So, i am yet to decide how i am going to heat my aquariums in my fish room. I am an engineer, so technical thinking is not a problem, but 'wattage' and 'power' is way out a structural engineers remit, so i am stuck!

The rule with aquarium heaters is 1 watt pet L. Lets say i have 10x 100L tanks (for ease of calculation). I would need a total of 1k watt of aquarium heaters. I would then hope the heat escape would heat the rest of the fish room too.

The other option is to heat the actual room. So i could get a heater and heat the room to the temp the fish need (say 24 degrees). Granted it would take a long time to heat the water, but once its up to temp, no problem.

Difference is that water holds heat much better than air does..... so MAYBE i would need a bigger heater if i were to heat the room. But, for arguments sake, lets say i don't.

So, the question is, do i need the same amount of wattage to heat the room as i would the aquariums?

The answer seems obvious, but it gets more complicated.

I was ready to shove in a 5kW heater into the room and off we go. BUt a friend who used to run breeding rooms for aquariums in Scotland swears by a different type of heater - Thermetubes

There are only around 200-300 watts. He reckons he runs all his fish rooms off two of these, so a total of about 600W and a cost of less than 80p a day! He said that they are much better as they are lower wattage/lower cost.

BUT, i don't understand! These things are not thermostatic, so they are on 24/7. So running cost is simple to calculate. But, if i put in a 5kw heater rather than these, it will be thermostatic, so won't be on all the time. So if it were on for a total of 5 hours a day, its 5hours x 5kw.

I guess my question is, what is cheapest?! Will a 5kw heater thats thermostatic use the same/more/less power to heat a room as one of therse 200w heaters? Assuming the end result for a room will be a constant temp.

There is a benefit in having the room heater - no cost of multiple aquarium heaters and no worry about them failing (which i have had a lot more than room electric oil filled room heaters!!).

 

[Blubble37]

just to let you know... 1 watt per litre ain't stedfast.... yo can run a 50 watt IME in a tank up to 75 litres! and a 100 watt in up to 150 litres and 150 watts in up to 225 litres... the other thing you could do is use a common sump and just heat that... but that increases the risk of disease spreading like wildfire from tank to tank....

 

[Tolak]

By heating that many tanks in a room you are effectively heating the room itself. If the room sits at 78F from the tank heaters, or the electric wall heater, utility costs will be roughly the same.

As mentioned, the savings is in not buying a ton of smaller heaters, as well as the cost of the electrical service to supply those heaters. From your fishroom topic I'm assuming you will run the electrical service yourself, there is the cost of materials to take into consideration. From what I've seen heating the room results in less evaporation issues, thus less condensation & the associated problems stemming from that.

Most often, and this is related to utility access & cost in an area, natural gas or some cheaper utility than electricity is used to heat a fishroom.

 

[Rorie]

By heating that many tanks in a room you are effectively heating the room itself. If the room sits at 78F from the tank heaters, or the electric wall heater, utility costs will be roughly the same.

As mentioned, the savings is in not buying a ton of smaller heaters, as well as the cost of the electrical service to supply those heaters. From your fishroom topic I'm assuming you will run the electrical service yourself, there is the cost of materials to take into consideration. From what I've seen heating the room results in less evaporation issues, thus less condensation & the associated problems stemming from that.

Most often, and this is related to utility access & cost in an area, natural gas or some cheaper utility than electricity is used to heat a fishroom.

Thanks for the replies.

I think the theory of one plug, rather than one per tank could have a huge factor. I am doing all the electrics myself, so it wouldn't make too much issue in the grand scheme of things.

I am unsure why it would effect evaporation though - any ideas?

Electricity is not cheap here....but either is the oil the rest of the house is heated on haha.

Any idea about using these 200W heaters rather than the 5kw? I did a volume calc online which says i need 4kw to heat the room, so should use a 5kw heater.

 

[Tolak]

My fishroom was originally a bedroom, 8'x16' roughed out, with 6 outlets. Had I known it was going to be a fishroom in the future I would have put in more outlets, as it is I was able to divide up the power between two circuits pretty easily. Large power strips mounted above tanks & racks make for easy outlet access with minimal worry about the bad mix of water & electricity.



I'm not sure on the science behind the evaporation, it's just something friends have noticed from switching to room heaters from tank heaters. Water condenses on cooler surfaces, so the room being at the same temperature as the tanks eliminates these cooler surfaces.



You have to look at the per BTU cost to figure which is cheaper. In some areas electric heat does end up being cheaper. Even with room heat, there are often a few heaters for tanks here & there for certain projects that require a bit warmer tank.



It's sort of like what's cheaper to heat a single tank, a 100w heater or a 200w heater. The power draw will be the same, the larger heater will run less. The 200w running all the time vs the 5kw running a fraction of the time roughly equals the same power consumption, not factoring in that perhaps that tube unit you linked to runs more efficiently.


You've got me looking at 5000 btu vent free gas heaters for my fishroom now, thanks! I swear, it's a never ending process, I just need to get it all done & turn my brain off.

 

[DrRob]

The thermatubes look like simple oil filled radiator type devices (although they may not be oil filled). No reason you can't run them off a thermostat, would be easy enough to wire into the mains supply to it, assuming they don't mind being switched too often.

IMHO the BTU requirement of a fishroom would depend on it's insulation. Pack the walls with something like celotex and then run whatever heater you think you'll need.

If you want to avoid oil and go green then you could go for something like an air to air heat pump, but I've no idea what price you'd be looking at for those.

 

[Rorie]

I am insulating the place to hell, but only with standard glass finer insulation. at £3 a roll there isn't much comparison to the kingspan etc. which building standards would ilke to see me use.

So i guess the question really is: Is wattage of a radiator directly related to the heat it gives off? i.e. i am being told these 200w heaters are enough, but calculators online say i need 5kw!

From above i take it that because i would nee the same wattage to heat the tanks as i would the room, then i need a 5kw...... I don't understand how this guy swears by the thermatubes though ....... i wouldn't think they provide enough heat....

 

[DrRob]

It'll depend on room size and rate of change, so you probably don't need 5kw. If you heat a room to 24C then everything in it will gradually change to 24C, it'll take longer to heat water than air as it has a much higher specific heat capacity, but it'll also take longer to cool down. Most of us are trying to heat a tank to well above the room temperature, so we have an uninsulated box that is leaking heat into the room, therefore needing increased heating.

With the room at the tank temperatures then you have less trouble with heat loss from evaporation.

Then it depends on the amount of heat loss despite insulation (don't forget the ceiling), from windows, from vents for the humidity and doorways/coming in and leaving. There's nothing wrong with glass fibre insulation, it just takes up more space for the same level of insulation. It's quite good for sound proofing as well.

Finally you need to remember the incoming things like water. Is the supply coming in at tank temperature, in which case it won't matter, or is it a cold supply, in which case you'll need to compensate for the cold input when you calculate your heating.

Oh, and wattage doesn't necessarily relate to heat output, just to energy consumed. Most electric heaters are fairly efficient and a lot of heating devices now quote heat output in watts which is a better reflection, rather than power input, which is what mains powered stuff will be required to quote. So keep an eye on what you're actually reading there.

 

[Rorie]

I am Still not sure what to do about the humidity/ventilation. Currently i have a dehumidifier in the house (in the fish room) but have no idea how much power its using. I wonder if that would be better than adding a vent. If i add a vent then i am also venting hot air..... which i don't want to do!

The roof is going to get a load of insulation as i have plenty of room above which is nice.

The input water will go into a storage tank so i'll have a big heater in there to boost that tank. I will also have a couple other tank heaters so i can manipulate individual tanks (such as my discus).

I wonder if these thermotubes work well because they have a large length, so heat is distributed in the room better, rather than a focused heat around a normal radiator? But i guess that would also have to do with ventilation/circulation of air.

 

[DrRob]

you can get heat exchanging vents, which make more sense the greater the difference in temperature between inside and outside air.

 

[Tolak]

The dehumidifier will also create some heat, this will help a bit. I've heard good things & bad things about the heat exchangers, regardless of which route you plan on going I would at least plan a vent for the room. Worst thing that could happen is that you would rarely if ever need it, but it is still available for use.

 

[BigC]

How much you willing to invest in this Rorie...would you stretch to full on air conditioning unit...

 

[coldcazzie]

The dehumidifier will use a lot of leccy, ours uses 400w per hour, so nearly 10kw a day. If you're already looking at huge bills for heating and filtration then you may not care, but I found the cost of running that was unacceptable, compared to the price of running my tanks, which is actually fairly small.

 

[Rorie]

The dehumidifier will use a lot of leccy, ours uses 400w per hour, so nearly 10kw a day. If you're already looking at huge bills for heating and filtration then you may not care, but I found the cost of running that was unacceptable, compared to the price of running my tanks, which is actually fairly small.

I have just got myself a sparky meter which will show me the cost of running it. It pulls about 750W when its on, but doesn't seem to be on that much! Time will tell! haha.

Cost of the fish room shouldn't be much though - one air pump to run all tanks and then the heating system which is potentially 50p a day according to this friend of mine if i go for his heaters....still don't understand haha

 

[Tizer]

personally, i would be buying the best insulation on the market, not cutting any corners with that, then heating the room itself to 22/23 degrees and then using heaters in the tanks that require that little extra. xD