Installing skylights in your home can help reduce your use of electricity, without lowering lighting levels. But, though skylights don't actually consume energy, they can be a cause of heat loss as your warm inside air escapes through the roof in winter. In summer, they can create a lot of solar heat gain ” which might cost you since you've got to run your air conditioning to compensate.
You can try tinted or light-reflective glass to reduce overheating, but this may also reduce the amount of daylight. Or, have some louvered blinds installed that can be directed to block direct sunlight but still let in light.
If your skylight can open, you can use it to provide ventilation, which will help cool your house and reduce your need for air conditioning. Hot air builds up near the ceilings ” opening a skylight releases the hot air, and allows cooler air to be pushed up from below.