Topic: Heat from Mining efficiency - page 2. (Read 3458 times)

Electric heat is generally described as 100% efficient due to full conversion of "fuel" to heat.

Yeah your rate may vary but here is my info as an example.
Electrical rate (total charge to the wall) $0.07 per kWh
Natural Gas Rate (total charge to the wall) $0.83 per ccf

1 cubic foot of natural gas has 1020 BTU.
nat gas is usually metered by the 100 cubic feet (ccf) so thats 102,000 BTU
1 kwh is 3412 BTU

So cost for 1 million BTU (arbitrary but I hate working with tiny numbers)
Natural Gas: $8.42 (1,000,000 / 102,000 * $0.83)
Electricity: $20.52 (1,000,000 /3412 * $0.07)

Now electrical resitance heating will always be 100% efficient (it simply can't be anything else).  A good heat pump (as long as you outside air doesn't get below 20F or so) can be 200% to 300% efficient but that doesn't apply to mining.    

At best a furnace* is going to be 97% efficient but most are in the 80% range.  Still at $8.43 / $20.52 =  41% even a malfunctioning furnace operating at 50% efficiency is going to be cheaper.   Nat gas is just crazy cheap in the US.  We keep finding more and more of it.   Hell they might start bringing back natural gas fired heat pumps again.

* Since there seems to be confusion by furnace I mean a device which burns combustible material (i.e. natural gas, propane, fuel oil, wood, garbage, human waste, etc).  Electric heat would be either resistance (100% efficiency) or heat pump (COP of >1 = >100% "efficiency").  At least in the US using the term furnace to refer to electric heat would be uncommon.

thanks yea totally meant ECONOMICS, by efficiency I guess I was implying financially. now there should be a price per kw and per cubic foot or whatever for natural gas where they are even in terms of cost to heat a house the same way (expel same BTU's)

gas (or any combustable heating source) can never be more than 100% efficient.  Law of conservation of energy.  1 BTU of chemical energy in natural gas can at most produce 1 BTU of usable heat.

The very best modern furnaces are 92% to 97% efficient.  Older cheaper furnaces are in the 80%.  If you have a furnace more than 20 years old it is likely is sub 80% efficiency. 

That being said you probably aren't interested in the EFFICIENCY on natural gas heat you are interested in the ECONOMICS.  Natural gas is very cheap in the US (in terms of $/BTU) so even at a lower efficiency the cost per BTU of heat added to the house will generally be less than a electric radiator (to include GPU rig).  How much cheaper?  Depends on a) electric rate, b) nat gas rate, c) furnace efficency but as a ballpark it is roughly 30% to 50% cheaper (per usable BTU).

woo. DO you know how much more efficient central heating is (by gas) to convection heaters? I'm sure I could find info online, thanks

IIRC, almost all power from a computer is wasted and expelled in the form of heat. I believe if you wanted to match the heat output of a 1.5KWh heater, you would need your mining hardware to pull the same amount of power from the wall. 2x 750W rigs would put out the same amount of heat.

What is the efficiency for heating using a mining rid let's say 5970 cards, as opposed to an electric heater (1.5kw/H) or even a central heater if you know