I personally would only use it for heating with a heat exchanger, not the air directly that it is blowing out. No matter how safe they are claimed to be.
The price you pay for an ASIC is just like any other high tech equipment, the actual material might be cheap, but you pay for the technology and knowledge behind the device. And as you said, YOU have to pay for THEM for investing in million $ manufacturing equipment, personnel etc. and this price is distributed in the price of ASICs.
Correct. The initial investment costs for 22nm ASIC dev and testing is at least 5-10 million which has to be amortize across the costs of the products. The question is merely one of scale. If the costs have to be amortized over a few thousand miners than those miners will be very expensive. What if those costs are amortized over mass consumer items though? Space heaters, water heaters, ect??? We are talking about millions of units. What if you could buy a hot water heater that actually paid some of your electrical bill with transaction fees and block rewards?
Think of the price of cell phones or computers initially and how cheap they are now. You can get a burner cellphone for 20 bucks! Netbooks are being sold for 230 and dropping!