A few nights ago, when it became clear that cold evenings were here to stay and wearing winter coats indoors was not a long-term solution, I fired up the boiler on our hot-water heat system. Our plans for evading Laclede Gas into November were thwarted, but we regained the warm indoor temperature needed to feel like doing anything other than huddle on the couch in the evenings.
Within a few minutes of starting the boiler, the house began to smell of hot water. The smell was pleasant, and foretold of the ten-degree rise in indoor temperature that occurred in the next hour with the thermostat set on a conservative 60 degrees (which is where it mostly will stay this winter).
The less pleasant result came later. We lost the company of our cats to the radiators -- at least, until they realized their warm friends could not feed them.