No — it is almost always cheaper to turn your heating off (or set it back) when rooms are unoccupied. Physics proves it. Turning back 8°F for 8 hours saves approximately 22–28% on that period's heating cost.
The rate at which a house loses heat is directly proportional to the temperature difference between inside and outside. A house at 70°F on a 30°F day (40°F difference) loses heat exactly twice as fast as a house at 50°F on the same day (20°F difference). Keeping your home warmer while you are away means it is constantly losing heat faster — requiring more energy to maintain that temperature.
The most common argument for leaving heating on is that reheating a cold house uses more energy. This is false. Yes, more energy flows in during the reheat phase — but the house also lost much less energy while it was cooler. The total energy used to maintain 68°F all day always exceeds the energy used to let it drop to 58°F and reheat before you return. The Department of Energy confirms this directly.
Cold-climate heat pumps (below 20°F outdoor temperatures) operate more efficiently at steady low output than cycling on and off at full power. In these conditions, a 2–4°F setback rather than a full 8–10°F setback may be more efficient. However, even in these cases, setbacks during long absences (8+ hours) still save energy.