What watt heater to power 1000 gallon pond

[Keagan Mast]

I am planning on buying a 1000 gallon pond and I want to know how many watts of heater power I need to keep it warm. I want to keep the pond temperature at 70-75 degrees and the temperature outside where I live will be from 28-40F in the winter.

 

[Yoimbrian]

It will depend a lot on how it's built. If you just use a pond liner you'll lose obscene amounts of heat through the bottom. If you built something with insulation you could lose near nothing from the bottom. Then for the top will it be covered at all during the winter, or wide open? What will your filtration look like? What about aeration? How high is your water table, will the bottom be touching water or dirt (water has WAY more heat transfer than dirt...)????

A real answer is impossible without all of the details, and a real answer is still extremely difficult even with all of the details.

Ballpark guess though, if you don't use insulation and keep an open top probably ~3,000 Watts. If you insulate the bottom and cover the top, especially during the winter, probably 1,000.

 

[Keagan Mast]

Without insulation on the bottom but a covered top will 1800 watts work?

It will depend a lot on how it's built. If you just use a pond liner you'll lose obscene amounts of heat through the bottom. If you built something with insulation you could lose near nothing from the bottom. Then for the top will it be covered at all during the winter, or wide open? What will your filtration look like? What about aeration? How high is your water table, will the bottom be touching water or dirt (water has WAY more heat transfer than dirt...)????

A real answer is impossible without all of the details, and a real answer is still extremely difficult even with all of the details.

Ballpark guess though, if you don't use insulation and keep an open top probably ~3,000 Watts. If you insulate the bottom and cover the top, especially during the winter, probably 1,000.

 

[TwoHedWlf]

Yeah, I agree with the "Extremely difficult to estimate" above. But, using this calculator: http://www.kernsanalysis.com/HeaterCalculator.cgi

And calling it a 5 foot cube, which is is going to lose a lot less heat than your likely shape especially with no insulation and plugging in .125" glass which insulates better than pond liner and a temperature difference of 50°F...

You're looking at a heating demand of 5825 watts. I wouldn't be surprised if that's on the low side. I don't know what your electricity costs are but here you'd be looking at $1300/month

I wouldn't be surprised if you're looking at a range from double to half that.

That kind of wattage you'd be best off investing in something like a big heat pump setup. A good high COP setup could probably cut that by 2/3rd.