My ex had some kookie plans to do exactly that. That's what he collected all those old dishes for (that got crushed and/or stolen).
He was going to start out heating a spa with one then try to move up from there.
I think that's pretty cool too, IMO. That kid with the mirrored primestar though, that's scary!
There must be a way to use that for your house for some good other than setting sticks and dirt on fire.
A friend of mine did that with an old 36" prime focus dish I had. He stripped the paint off of it completely, and polished the metal so it was mirror-like. It would set fire to anything in its focal point almost instantly, very dangerous IMO. Made a good demonstration of why we shouldn't paint our dishes with anything other than flat paint ...