Yes it is, when you ignore the cost of the free labour and most of the components of the system's you're installing.
Take the wind turbine in last weeks episode; "Only a few hundred quid." Yeah, right, if you ignore the cost of the tower, cabling, control gear and battery bank. In actual fact, that installation would cost between ten and twenty thousand pounds if you had to pay for everything, and the pay-back time approaches infinity. Always assuming that the planners would let you put it up in the first place.
And as for his bonkers "everything synthetic is evil" wife ...