Heating a Tank in Cold Climates

[JoshH]

Unfortunately only 1 of the 3 garage spaces is mine and they are all finished. So I'd have to tear down sheetrock which is definitely not worth the effort. Instead, when I replace my carpet in the next couple years, I'll be sure to put down some nice thick carpet padding.

Hate to say this but carpet padding more than likely isn't going to do very much heat wise. will make it nice and soft on your toes though lol. In my experience as an insulator Unless your home is Air tight and air loss is minimal you're not going to save much when dropping the temp during the day. how often your furnace stops and starts won't change much either it will only be beneficial while the temp drops to the point you set it at, once it reach's that point it's going to turn on and off the same amount as if you had it set for a warmer temp. Just my 2 cents but I'd say stick with keeping your temp up close to where you are comfortable and let the heaters do the rest.

 

[JoshH]

Oh and if you do blow in, don't go with the celulous *Paper* garbage, settles WAY faster than blown in fiberglass.

 

[jason.kennedy.98478]

I have the same volume tank with a 50w heater and open top. I set the temp on the heater to 82 and it kept the tank at 76 to 78. Room temp was in the 40s i have sense gotten a space heater and my room is in the low 60s and turned the heater down to 78 and all is good

 

[whs6704]

I'm curious what the trade off for cost/efficiency would be to run an aquarium heater hard with room temp in the 50's vs keeping the room temp in the 70's.

Living in MN I would like to let me heat go down into the 50's during the day while I'm at work to save on utilities. However, I'm concerned that will just cause my electricity bill to rocket up with the tank heaters being run so much.

I live in a 800 sq ft condo and have a 10 gallon nano. Tank temp is 78. Current heater is a 25W but I am having to upgrade to a 50W as the 25W is unable to keep the tank at 78 if room temp is below 70.

Anyone have experience with this?

Hope u know that letting heat stay off till u get home and the room temperature is at 50 and turning the heat back on till it reaches 74 d. Is costing you more the a 50w heater running 24/7

 

[bhuyett]

I keep my house 69 degrees and these last couple days have verified that I should be good. 29 degree weather today. My 120 gallon tank and 40 gallon dump, doesn't fluctuate more that 0.5 degrees

.

 

[Waterjockey]

Hate to say this but carpet padding more than likely isn't going to do very much heat wise. will make it nice and soft on your toes though lol. In my experience as an insulator Unless your home is Air tight and air loss is minimal you're not going to save much when dropping the temp during the day. how often your furnace stops and starts won't change much either it will only be beneficial while the temp drops to the point you set it at, once it reach's that point it's going to turn on and off the same amount as if you had it set for a warmer temp. Just my 2 cents but I'd say stick with keeping your temp up close to where you are comfortable and let the heaters do the rest.

It will turn on far less often. It's more involved than this, but basic formula for thermal conductance (ie through a wall, window, whatever) is Q = kA (higherTemp - coldertemp)t/ d
k is the thermal constant of the material, A is cross sectional area, t is time (s) and d is thickness of material.
So if it is 10 deg C outside and you keep your house at 20 deg C that is a 10 deg temp difference (temphot-Temp cold). If you keep the house at 15 deg C...the temp difference drops to 5 deg. Plug that into the formula, and the 10 deg difference vs 5 deg difference is almost double the heat loss rate...for poorly or non insulated surfaces (windows, or the non or poorly insulated ga rage wall for example. The furnace has to run twice as much to maintain the 10 deg difference as the 5 deg difference. Insulation changes the tHerman constant so it becomes less and less "drastic" than double the rate for the example above, however, the higher temperature difference drives much higher heat loss rates.
It's obviously slightly more complicated with composite walls (ie, drywall, insulation, siding, plus, as you mentioned, air leaks. (This is just conductance..there is convection and radiant losses as well..but they only serve to increase heat loss rate more often than not in the premise we are discussing) But we can calculate a pretty close constant for composite walls and ballpark accurately enough how much heat is lost. No guessing required. The math proves it out.

 

[JoshH]

It will turn on far less often. It's more involved than this, but basic formula for thermal conductance (ie through a wall, window, whatever) is Q = kA (higherTemp - coldertemp)t/ d
k is the thermal constant of the material, A is cross sectional area, t is time (s) and d is thickness of material.
So if it is 10 deg C outside and you keep your house at 20 deg C that is a 10 deg temp difference (temphot-Temp cold). If you keep the house at 15 deg C...the temp difference drops to 5 deg. Plug that into the formula, and the 10 deg difference vs 5 deg difference is almost double the heat loss rate. The furnace has to run twice as much to maintain the 10 deg difference as the 5 deg difference.
It's obviously slightly more complicated with composite walls (ie, drywall, insulation, siding, plus, as you mentioned, air leaks. But we can calculate a pretty close constant for composite walls and ballpark accurately enough how much heat is lost. No guessing required. The math proves it out.

You would have to use that formula for each material in a wall and average it out for that to be even remotely useful. Different materials have EXTREMELY different conduction rates obviously so saying it would come on twice as much between 10 and 5 degrees is a very broad stroke. And as you agreed, there are numerous factors effecting your equation. The wall could be air tight and packed with insulation, but combine that with a single pane window and your equation would have a completely different result than if it were a triple pane window. Too many variables IMO to go of an equation. Best thing just to take a couple months and test the theory. Every house is different, condos obviously have some benefits in this situation. Most energy companies divide your consumption weekly, even daily so you could do a couple weeks of each and compare the two.

 

[Waterjockey]

You would have to use that formula for each material in a wall and average it out for that to be even remotely useful. Different materials have EXTREMELY different conduction rates obviously so saying it would come on twice as much between 10 and 5 degrees is a very broad stroke. And as you agreed, there are numerous factors effecting your equation. The wall could be air tight and packed with insulation, but combine that with a single pane window and your equation would have a completely different result than if it were a triple pane window. Too many variables IMO to go of an equation. Best thing just to take a couple months and test the theory. Every house is different, condos obviously have some benefits in this situation. Most energy companies divide your consumption weekly, even daily so you could do a couple weeks of each and compare the two.

Thanks. Yes, I tried to get across I simplified the heck out of it to explain how thermal conductance works. I tried to note this would be closest to the poorly insulated garage wall mentioned, or simple pane windows....and yes the constant improves the better the material and insulation values. The formula was given so anyone could see that for themselves. But it's not really that difficult to work out a composite material wall, and openings for windows etc. Thankfully, for the most part, not necessary. There are reference texts galore where with constants for the most common types of construction, be it masonry, wood, drywall, plaster, type of insulation, vapour barriers etc. You just look up the constant and plug in the area..of course now there are spreadsheets and online calculators where you plug in window size, type of windows, type of doors, wall dimensions etc...and it's all done for you with a few mouse clicks. Technology had made the task simpler and easier, but the thermodynamics behind it remain the same. Higher temperature differences drive higher heat rate transfers...(or in this case, higher heat rate loss).and temperature difference is the "heavy hitter" in the equations. Engineers, Architects and the like used to do these type of calcs when designing heating/cooling systems for buildings. Again, technology has simplified the tasks considerably.

Another way I try to explain it is imagine a barrel of water with a tap dripping water out (the lower temperature house, the rate of water emptying is the heat loss rate) all day long. Yes, when you get home, you have to fill the barrel back up (heat the house internals up again).
Compare that to a barrel with the faucet running at a steady stream all day. You have to keep a steady stream of water pouring in (heat) to keep the barrel at the same level (same temp all day). At the end if the day, you've used a lot less water to fill the dripping barrel back up, than you used to feed the barrel with the steady stream all day long.

 

[JoshH]

I understood you're original explanation just as easily as the barrel but it's still a generalization. Everything is entirely dependent on the actual materials to properly determine heat loss rate. Either way I think I'm going to have to agree to disagree on this lol Like I said it's only by trying it both ways and comparing that he would know the answer to his question as we don't really know the make up of his condo or the condition of any of the insulating materials.

 

[Waterjockey]

We can agree to disagree, and I'll just leave it there

 

[JoshH]

lol sounds good to me

 

[mardoon]

I am in Michigan keep temp and in house around 67 year around. And my sump is in basement: winter temp of tank avg 77 -78.5

 

[Damon]

I keep my house 69 degrees and these last couple days have verified that I should be good. 29 degree weather today. My 120 gallon tank and 40 gallon dump, doesn't fluctuate more that 0.5 degrees

.

Same here.. But I'm sure you have your parameters as far as the temp range nice and tight like mine.. Mine goes from 77.6 to 78.0, and I am in Michigan, with the system in the basement of a townhouse, the temperature of the house set(and stays) at 68 year round..

I think something important also to consider is the "type" of heater your using.. I abandoned traditional heaters long, long ago, partly for the reason your mentioning.. The fluctuation is too great for my personal tastes, and they take far too long to heat, if they actually ever get to the temperature range you want..

Because you have a controller, and overall the titanium heating elements are, at least in my experience, infinitely better.. They heat faster, you can set a much tighter range, they heat more effectively, they are much, much smaller physically, and, you typically don't have to run as high a wattage element as you do a normal heater..

For example, I have two elements on my system(240 gallons twv). One 500 and one 250. But the 500 is the primary one that that comes on 99% of the time.. The only time the 250 comes on is when I add new water for the water change, and even then, it comes on and goes off in 5 to ten minutes.. The 250 is set at a lower triggering range as a failsafe.. And both of course controlled by my apex..

But I think you honestly will find more effective heating with elements, in conjunction with using your controller, in your situation.. And tighten your range within your controller so it doesn't drop as much if you get one.. With the combination of an element and controller monitoring and maintaining the temp, you cab get ridiculously stable..

 

[mardoon]

Same here.. But I'm sure you have your parameters as far as the temp range nice and tight like mine.. Mine goes from 77.6 to 78.0, and I am in Michigan, with the system in the basement of a townhouse, the temperature of the house set(and stays) at 68 year round..

I think something important also to consider is the "type" of heater your using.. I abandoned traditional heaters long, long ago, partly for the reason your mentioning.. The fluctuation is too great for my personal tastes, and they take far too long to heat, if they actually ever get to the temperature range you want..

Because you have a controller, and overall the titanium heating elements are, at least in my experience, infinitely better.. They heat faster, you can set a much tighter range, they heat more effectively, they are much, much smaller physically, and, you typically don't have to run as high a wattage element as you do a normal heater..

For example, I have two elements on my system(240 gallons twv). One 500 and one 250. But the 500 is the primary one that that comes on 99% of the time.. The only time the 250 comes on is when I add new water for the water change, and even then, it comes on and goes off in 5 to ten minutes.. The 250 is set at a lower triggering range as a failsafe.. And both of course controlled by my apex..

But I think you honestly will find more effective heating with elements, in conjunction with using your controller, in your situation.. And tighten your range within your controller so it doesn't drop as much if you get one.. With the combination of an element and controller monitoring and maintaining the temp, you cab get ridiculously stable..

ty!

 

[Damon]

ty!

Np!

 

[McGee]

What if you were to go to Home Depot and get a sheet of 1" foam board and box in the four sides leaving the top open for air and light!

 

[JayC]

You can run all the equations you want .... and attempt to apply it all to your house. GOOD LUCK. That advice and barrel theory is dead wrong. After you pull your face out of 'google', and apply/ accumulate ALL of your data over the ENTIRE process of temp. fluctuation, the end results will speak for themselves. So I'll say it one more time, .... you're better off leaving it constant! Oh, and by the way, I AM a Custom Home Builder with a degree in, ....you guessed it...., architecture !

 

[Waterjockey]

You can run all the equations you want .... and attempt to apply it all to your house. GOOD LUCK. That advice and barrel theory is dead wrong. After you pull your face out of 'google', and apply/ accumulate ALL of your data over the ENTIRE process of temp. fluctuation, the end results will speak for themselves. So I'll say it one more time, .... you're better off leaving it constant! Oh, and by the way, I AM a Custom Home Builder with a degree in, ....you guessed it...., architecture !

Dead wrong?
Yes, why bother with thermodynamic equations when talking about heat transfer? ASHRAE might as well drop all that stuff from thier industry periodicals and courses.

It's never, ever, efficient to lower the temp when the space isn't occupied?

My face wasn't in Google. That comes from various texts like, Thermodynamics, an Engineering Approach, Modern Refrigeration and Air Conditioning, Engineering Thermodynamics, Applied Physics. Stuff I used when getting my gas ticket, refrigeration ticket, and my Power Engineering ticket.

Would you care to elaborate as to why it is "dead wrong" ("dead", implying all cases, all the time), other than a "I said so" kinda reply?
Even just a link to a credible source in the thermodynamics world?

 

[Ocean Lotion]

You can run all the equations you want .... and attempt to apply it all to your house. GOOD LUCK. That advice and barrel theory is dead wrong. After you pull your face out of 'google', and apply/ accumulate ALL of your data over the ENTIRE process of temp. fluctuation, the end results will speak for themselves. So I'll say it one more time, .... you're better off leaving it constant! Oh, and by the way, I AM a Custom Home Builder with a degree in, ....you guessed it...., architecture !

The cost savings to lowering the temp in a room would be dependant on how long that duration is. A long duration and you would save $. A short duration like during the work day - no savings. When I go to bed at night I toss a blanket over my tank. I do have to make sure I take it off the next day before the lights with their fans come on.

 

[Waterjockey]

Without getting "complicated" with formulas and stuff, here's a link to Stats can (Statistics Canada), discussing programmable thermostats and research done at the Canadian Center for Housing Technology.
http://www.statcan.gc.ca/pub/16-001-m/2008006/5212652-eng.htm
For example. Empirical research demonstrated a 13% drop in use of natural gas, and about 2% drop in electrical use when setting the thermostat back during the day.
6% savings at night.

But hey, no math