user95422: If someone want to heat a room or some water for a defined amount of time and without a worry about the sound produced.
Can a bitcoin miner be a good subtitute to a modern heather with the same power consumption ?

user112775: Yes, it is possible to use the waste heat of a bitcoin miner (or any other computing device or other machinery) to heat your living space.
The plan has some drawbacks and limitations:

The temperature:
These devices are efficient when they get like ~20C at the inlet and heat air to less than 40C. Trying to make them work at higher temperature may limit their clock frequency and/or useful life. This leads us to:

Noise:
You cannot put the miner much further away from the living space. It has to be inside or near (with air ducts). You'll get all the noise. They make a lot of noise.

Control:
Unless you are living in some very cold place, you will need to control the heat output from 0 to some value related to your house. There are few methods, but all of them require lowering the mining output. This means lowering the return of investment (and mining is actually quite competitive, so you will end up losing money).


Another variant is to redirect the excessive heat output somewhere else (i.e. outside). Or use the normal means of heating and only supplement it with the miners (if you have a large house and few mining devices)..

Dust
These devices require relatively clean environment, or they collect dust. Dust makes them overheat or makes you periodically disassemble and clean them.

What I did in a similar situation:
I had to host few servers at home for a while.
They ended up in the garage under the house. The heat they generated was beneficial for heating the whole house. The floor was +5..+7C, the noise didn't penetrate the floor and the dust was manageable.

user13866: 
Can a bitcoin miner be a good subtitute to a modern heather with the same power consumption ?

A Bitcoin mining rig lacks certain features that are fairly desirable in a room heater. The main one is a thermostat. Even if it did, this would mean you would have to throttle back your Bitcoin miner as the room reaches some desired temperature. You would also need to do less mining in the summer than in winter. Whether reduced mining activity in those situations is acceptable is up to you, of course.

If someone want to heat a room or some water

Heating water is typically a very different proposition. If, for example, you wanted to boil water to make tea, a Bitcoin miner would probably be a very bad place to start.

Although a Bitcoin miner will make a room hot, it isn't going to be particularly good for anything other than what it was designed for.

user107094: Heat Quality
Not all heat is the same.  The earth maintains a fairly constant average of 10 C near the surface, but you can't boil water with that.  So the temperature of your heater makes a big difference for the uses you can apply it.  If you want your hot water to get to 50 C, but your ASIC miner only generates 40 C of heat, then you are in for a tepid shower at best.  On the other hand, if you integrated your bitcoin miners with your HVAC/water heater, you could avoid venting the excess heat.  Since your cold water input will almost certainly be much colder than your miners, you can always pre-heat your water with miners, and basically put all your waste heat to good use.
A typical water heater consumes around 12 kWh/day (4 kW x 3 hours).  A small miner consumes about 1.2 kW.  So in 10 hours, it will generate as much thermal energy as your water heater, more or less.  Unless you take a lot of really hot showers/laundry/wash dishes, you should probably buddy up with a neighbor (more convenient in an apartment/condo) to share the excess heat.  Of course, you aren't going to make much money with a single miner, but perhaps you could reduce your water heating bill slightly (by investing thousands of dollars in a miner...not really a smart investment).
A room electric heater might consume 1.5 kW and run for 4-6 hours per day, for a usage of 6-9 kWh.  That's another 6-7 hours of mining, so you might be able to heat your whole small apartment on one miner.
Return on Investment
For about $1200 you can get an Antminer R4 and 8.6 TH/s at 1.3 kW of power.  Your expected Bitcoin revenue for the year with this rig is about $500.  If you are able to replace 1.3 kW of electric heating in your home with this rig, you will basically earn $500/yr. towards your electric bill (which is expected to be higher, unless you live in an area with very cheap electricity).  It should pay for itself in about 2.5 years (not counting all the work of replacing your heating system with the mining rig, which is probably more expensive than the miner itself).

user42829: It may be practical to use a miner to provide some of the heat for your home, bringing some miners into your home during the cooler months and moving them elsewhere during summer.
It's pretty much 100% efficient at converting electric energy into heat energy.  (vs. a heat pump being about 300% efficient1, moving existing heat from outdoors as well).  Even a lightbulb that turns some power into visible light will ultimately heat the room when that light is absorbed by the walls.  (Unless some light escapes out windows).  A fan moves air, but that air movement energy ultimately ends up as heat unless the moving air goes out a window.  More-ordered (low entropy) forms of energy naturally convert to high-entropy non-concentrated heat; heating a room is one time the 2nd law of thermodynamics is on your side.  (However, the 2nd law is why heat wants to flow from your warm house to the cold outdoors; that's why you insulate your walls.)  TL:DR: pretty much any form of energy can efficiently turn into heat.
Footnote 1: Modern heat pumps often have something like 330% efficiency when not too cold outside. According to this Canadian government page about heat pumps, air source heat pumps typically achieve a 3.3 ratio of heat out to input power at 10°C (cool day), or 2.3 at -8.3°C (well below freezing).
So they're about 230 to 300% efficient most of the year.  vs. 100% for a fully indoor space heater or computing equipment.  Using electric power to run a miner instead of a heat pump is an opportunity cost, if it would be possible to install a heat pump.  So the coins you mine have an opportunity cost: you could have gotten more heat for the same power input.

But if you were going to be using electricity to do any mining at all, using the heat output for something useful is good, when possible.  If the alternative is putting your mining rig in an uninsulated shed or something and still needing to heat your home, that's worse than having some mining power heating part of your house.
As others have pointed out, you wouldn't want to try to provide all the heating via mining: heating needs are highly variable (depending on weather, sunlight through the windows, and other heat sources like using your oven for cooking), but you normally want your bitcoin mining to be on all the time.  (To pay for the initial investment of buying the expensive hardware which costs much more than a dumb space heater; basically just some resistive wire that you put voltage across.)
The amount of mining power you can have indoors in a given month without causing a problem is approximately the best case (smallest) amount of heating that you'll need at any time that month.  The rest of the heating load should come from thermostat-controlled regular heating, like a heat pump, oil or gas, or worst case dumb electric heat that just gets hot.  (And hopefully that heating system distributes heat around your home better than a miner in one spot, modulo whatever air circulation you arrange to move the mining heat around.)
This "safe" amount of mining might be a few hundred watts, again depending on the month and the size of your home, and if you can hook it up to an existing air circulation mechanism to distribute heat around instead of making one room hot.
If you had more mining power indoors, you'd need some of it on a thermostat, to shut itself down when the room gets above human-desired temperature.  (Or put it in an uninsulated basement where it keeps your floors warm, but lots of extra heat can just escape into the ground.  Or in the winter, an attic.)
If you have some older less-efficient miners, setting up your computer to stop those first when the temperature rises could make sense.  You wouldn't want to buy a lot of mining hardware that would only be on part of the time; that wouldn't be worth the investment.  But some semi-obsolete gear could be worth running if the power was effectively cheaper (because you need the heat anyway, and don't have a heat pump).
Bitcoin mining is arguably not a great thing to dump a lot of electrical power into (for environmental reasons), so I'm certainly not suggesting trying to max out your mining by using it to heat your house.  Especially if you can get a heat pump instead, and/or your local area doesn't have more renewable energy than it can use (so extra power use means more oil or coal being burned somewhere).
But if you do want to mine anyway, use some of that waste heat in the winter.

user208: A device that consumes N watts of power (and doesn't output electricity or some other form of energy) will eventually produce N joules of heat per second.
Thus, if your goal is converting electricity to heat, every piece of hardware that consumes electricity is 100% efficient. It's completely irrelevant what happens with that electricity before it becomes heat.
Of course, you need to take hardware depreciation/maintenance costs into account.
Also of note: as heating devices, heat pumps have over 100% efficiency, as they simultaneously consume electricity (which is turned into heat) and move additional heat from a colder area to a hotter one.

95422: <p>If someone want to heat a room or some water for a defined amount of time and without a worry about the sound produced.</p>
<p>Can a bitcoin miner be a good subtitute to a modern heather with the same power consumption ?</p>
 112775: <p>Yes, it is possible to use the waste heat of a bitcoin miner (or any other computing device or other machinery) to heat your living space.</p>
<p>The plan has some drawbacks and limitations:</p>
<ol>
<li><p>The temperature:
These devices are efficient when they get like ~20C at the inlet and heat air to less than 40C. Trying to make them work at higher temperature may limit their clock frequency and/or useful life. This leads us to:</p>
</li>
<li><p>Noise:
You cannot put the miner much further away from the living space. It has to be inside or near (with air ducts). You'll get all the noise. They make a lot of noise.</p>
</li>
<li><p>Control:
Unless you are living in some very cold place, you will need to control the heat output from 0 to some value related to your house. There are few methods, but all of them require lowering the mining output. This means lowering the return of investment (and mining is actually quite competitive, so you will end up losing money).</p>
</li>
</ol>
<p>Another variant is to redirect the excessive heat output somewhere else (i.e. outside). Or use the normal means of heating and only supplement it with the miners (if you have a large house and few mining devices)..</p>
<ol start="4">
<li>Dust
These devices require relatively clean environment, or they collect dust. Dust makes them overheat or makes you periodically disassemble and clean them.</li>
</ol>
<p>What I did in a similar situation:
I had to host few servers at home for a while.
They ended up in the garage under the house. The heat they generated was beneficial for heating the whole house. The floor was +5..+7C, the noise didn't penetrate the floor and the dust was manageable.</p>
 13866: <blockquote>
<p><strong>Can a bitcoin miner be a good subtitute to a modern heather with the same power consumption ?</strong></p>
</blockquote>
<p>A Bitcoin mining rig lacks certain features that are fairly desirable in a room heater. The main one is a thermostat. Even if it did, this would mean you would have to throttle back your Bitcoin miner as the room reaches some desired temperature. You would also need to do less mining in the summer than in winter. Whether reduced mining activity in those situations is acceptable is up to you, of course.</p>
<blockquote>
<p><strong>If someone want to heat a room or some water</strong></p>
</blockquote>
<p>Heating water is typically a very different proposition. If, for example, you wanted to boil water to make tea, a Bitcoin miner would probably be a very bad place to start.</p>
<hr />
<p>Although a Bitcoin miner will make a room hot, it isn't going to be particularly good for anything other than what it was designed for.</p>
 107094: <h1>Heat Quality</h1>
<p>Not all heat is the same.  The earth maintains a fairly constant average of 10 C near the surface, but you can't boil water with that.  So the <em>temperature</em> of your heater makes a big difference for the uses you can apply it.  If you want your hot water to get to 50 C, but your ASIC miner only generates 40 C of heat, then you are in for a tepid shower at best.  On the other hand, if you integrated your bitcoin miners with your HVAC/water heater, you could avoid venting the excess heat.  Since your cold water input will almost certainly be much colder than your miners, you can always pre-heat your water with miners, and basically put all your waste heat to good use.</p>
<p>A typical water heater consumes around 12 kWh/day (4 kW x 3 hours).  A small miner consumes about 1.2 kW.  So in 10 hours, it will generate as much thermal energy as your water heater, more or less.  Unless you take a lot of really hot showers/laundry/wash dishes, you should probably buddy up with a neighbor (more convenient in an apartment/condo) to share the excess heat.  Of course, you aren't going to make much money with a single miner, but perhaps you could reduce your water heating bill slightly (by investing thousands of dollars in a miner...not really a smart investment).</p>
<p>A room electric heater might consume 1.5 kW and run for 4-6 hours per day, for a usage of 6-9 kWh.  That's another 6-7 hours of mining, so you might be able to heat your whole small apartment on one miner.</p>
<h1>Return on Investment</h1>
<p>For about $1200 you can get an Antminer R4 and 8.6 TH/s at 1.3 kW of power.  Your expected Bitcoin revenue for the year with this rig is about $500.  If you are able to replace 1.3 kW of electric heating in your home with this rig, you will basically earn $500/yr. towards your electric bill (which is expected to be higher, unless you live in an area with very cheap electricity).  It should pay for itself in about 2.5 years (not counting all the work of replacing your heating system with the mining rig, which is probably more expensive than the miner itself).</p>
 42829: <p>It may be practical to use a miner to provide <em>some</em> of the heat for your home, bringing some miners into your home during the cooler months and moving them elsewhere during summer.</p>
<p>It's pretty much 100% efficient at converting electric energy into heat energy.  (vs. a heat pump being about 300% efficient<sup>1</sup>, moving existing heat from outdoors as well).  Even a lightbulb that turns <em>some</em> power into visible light will ultimately heat the room when that light is absorbed by the walls.  (Unless some light escapes out windows).  A fan moves air, but that air movement energy ultimately ends up as heat unless the moving air goes out a window.  More-ordered (low entropy) forms of energy naturally convert to high-entropy non-concentrated heat; heating a room is one time the <a href="https://en.wikipedia.org/wiki/Second_law_of_thermodynamics" rel="noreferrer">2nd law of thermodynamics</a> is on your side.  (However, the 2nd law is why heat wants to flow from your warm house to the cold outdoors; that's why you insulate your walls.)  TL:DR: pretty much any form of energy can efficiently turn into heat.</p>
<p><strong>Footnote 1:</strong> Modern heat pumps often have something like 330% efficiency when not too cold outside. According to this Canadian government <a href="https://www.nrcan.gc.ca/energy-efficiency/energy-star-canada/about-energy-star-canada/energy-star-announcements/publications/heating-cooling-heat-pump/air-source-heat-pumps/6831" rel="noreferrer">page about heat pumps</a>, air source heat pumps typically achieve a 3.3 ratio of heat out to input power at 10°C (cool day), or 2.3 at -8.3°C (well below freezing).</p>
<p>So they're about 230 to 300% efficient most of the year.  vs. 100% for a fully indoor space heater or computing equipment.  Using electric power to run a miner instead of a heat pump is an opportunity cost, if it would be possible to install a heat pump.  So the coins you mine have an opportunity cost: you could have gotten more heat for the same power input.</p>
<hr />
<p><strong>But if you were going to be using electricity to do any mining at all, using the heat output for something useful is good, when possible.</strong>  If the alternative is putting your mining rig in an uninsulated shed or something <em>and</em> still needing to heat your home, that's worse than having some mining power heating part of your house.</p>
<p><strong>As others have pointed out, you wouldn't want to try to provide <em>all</em> the heating via mining</strong>: heating needs are highly variable (depending on weather, sunlight through the windows, and other heat sources like using your oven for cooking), but you normally want your bitcoin mining to be on all the time.  (To pay for the initial investment of buying the expensive hardware which costs <em>much</em> more than a dumb space heater; basically just some resistive wire that you put voltage across.)</p>
<p>The amount of mining power you can have indoors in a given month without causing a problem is approximately the best case (smallest) amount of heating that you'll need at any time that month.  The rest of the heating load should come from thermostat-controlled regular heating, like a heat pump, oil or gas, or worst case dumb electric heat that just gets hot.  (And hopefully that heating system distributes heat around your home better than a miner in one spot, modulo whatever air circulation you arrange to move the mining heat around.)</p>
<p>This &quot;safe&quot; amount of mining might be a few hundred watts, again depending on the month and the size of your home, and if you can hook it up to an existing air circulation mechanism to distribute heat around instead of making one room hot.</p>
<p>If you had more mining power indoors, you'd need some of it on a thermostat, to shut itself down when the room gets above human-desired temperature.  (Or put it in an uninsulated basement where it keeps your floors warm, but lots of extra heat can just escape into the ground.  Or in the winter, an attic.)</p>
<p>If you have some older less-efficient miners, setting up your computer to stop those first when the temperature rises could make sense.  You wouldn't want to buy a lot of mining hardware that would only be on part of the time; that wouldn't be worth the investment.  But some semi-obsolete gear could be worth running if the power was effectively cheaper (because you need the heat anyway, and don't have a heat pump).</p>
<p>Bitcoin mining is arguably not a great thing to dump a lot of electrical power into (for environmental reasons), so I'm certainly not suggesting trying to max out your mining by using it to heat your house.  Especially if you can get a heat pump instead, and/or your local area doesn't have more renewable energy than it can use (so extra power use means more oil or coal being burned somewhere).</p>
<p>But if you do want to mine anyway, use some of that waste heat in the winter.</p>
 208: <p>A device that consumes N watts of power (and doesn't output electricity or some other form of energy) will eventually produce N joules of heat per second.</p>
<p>Thus, if your goal is converting electricity to heat, every piece of hardware that consumes electricity is 100% efficient. It's completely irrelevant what happens with that electricity before it becomes heat.</p>
<p>Of course, you need to take hardware depreciation/maintenance costs into account.</p>
<p>Also of note: as heating devices, heat pumps have over 100% efficiency, as they simultaneously consume electricity (which is turned into heat) and move additional heat from a colder area to a hotter one.</p>
