I used to heat my whole house with mining rigs this and last winter. I had at least one in every room and rest of them in the balcony. It actually got so warm every day that I had to open all the doors and windows for cooling the place down. Average temp during the winter is/was about -10C I think.
If I was generating that much heat, I'd probably figure out a way to heat my hot water with it too...lol.
I used to have a window semi-open in my room 24/7 with temperatures up to -15C during the day and up to -25C at night. OTOH it started to get very cold when I had Internet problems (even after I would close the window until my connectivity returned).
There was a guy on the forums who made a good use of his rigs' heat 2 years ago:
Another thing: WAF!
I have a liquid cooled miner. It is dead silent, but the main point is that it heats our bathroom floor. Pictures says more than words, so I attached a few.
My computer. An oldish Athlon64 X2 in a cabinet from a previous century. Sorry about the mess. The cabinet is usually closed for optimal airflow. You see the water tube entering at the bottom, water passing through the 5970 water block (the shop were sold out of nipples fitting my tubing, and put in some 1/2" tubing and adapters, so it is a bit messy in there), then through my CPU block before heated water leaves at the top. The direction has a purpose. If I start the computer with no pump, the water will flow by itself due to convection. Convection isn't enough for cooling the 5970 as well, so the pump must be running when mining. And compare the size of the stock cooler in the lower right corner with the water block. The card is now half as thick, and the PCI socket next to it is usable again!
Tubes going up through the roof above. This is not finished. I'll make better connectors closer to the ceiling and box them in later. The thing on the tube to the right is a flow indicator. The cable coming out of the same hole and going to a RJ45 socket (not connected yet), connects a series of temperature sensors embedded in the floor and walls, and a temperature and humidity sensor next to the fan in the bathroom.
Tubes under my bathroom floor and one of the temperature sensors (inside a blue shrink hose). This is now buried in cement and covered with nice tiles.
Reservoir where the water returns. Inside there is a small pump (300 l/min, 0.5m head), which keeps the water flow going and bubbles out of the tubes. Water level inside here is 0-level. In the tubes above the water level in the reservoir, there is actually a vacuum, and the water pressure inside my computer is low.
The best thing about my water cooling and floor heating is that my wife keeps nagging me to buy a second 5970 to make the floor warmer. Beat this with a air cooled system. :-)
Not related but interesting: