it might just take the rest of the evening to get back to anywhere near desirable temperatures
What do you live in? A mediaeval castle? Or are your radiators and boiler woefully under-specified? (Or you might find that your radiators are full of sludge and emitting heat at less than a third of their rated output).
I've always programmed the timer to turn the boiler off at the time I leave for work and on again about half an hour before I'm expecting to get back. Plenty warm enough when I get in. This in a Victorian solid-walls flat with draughty sash windows (albeit with the assistance of waste heat from downstairs who are always in)
Being able to turn it on using my cellphone, or even better to program my cellphone to turn on the heating when the GPS tells it that I have started my return journey, would save me significant amounts of money and CO2 emission.