Your plants will be fine without the light for a week.
However, I would be more concerned about how your plants will do WITH the light. Too much light, without injecting CO2, may cause them to suffer and encourage algae growth. Do you know what the light intensity will be at the substrate in terms of PAR? If not, perhaps you can post which bulbs you are installing and how far the bublbs will be from the substrate. Then, maybe some of us that use T5's can advise.
Also, make sure that you provide enough nutrients.