No, warming and keeping a room at 22°C generally requires more energy than keeping it at 17°C. The amount of energy needed to maintain a certain temperature in a room depends on various factors, including the insulation of the room, outside temperature, and the heating system used.
When you increase the temperature from 17°C to 22°C, you are essentially raising the set point for the heating system. The heating system will have to work harder and consume more energy to maintain the higher temperature. The exact amount of energy consumed will depend on the efficiency of the heating system and other factors mentioned above.
On the other hand, keeping a room at a lower temperature, such as 17°C, requires less energy because there is a smaller temperature difference between the desired temperature and the outside temperature. The heating system doesn't need to work as hard to maintain the lower temperature, resulting in lower energy consumption.
It's worth noting that the specific energy consumption can vary depending on the type of heating system used, such as electric heaters, gas furnaces, or heat pumps. Each system has its own efficiency characteristics and energy requirements.