Solar models and electron screening

We investigate the sensitivity of the solar model to changes in the nuclear reaction screening factors. We show that the sound speed profile as determ ined by helioseismology certainly rules out changes in the screening factor s exceeding more than 10%. A slightly improved solar model could be obtaine d by enhancing screening by about 5% over the Salpeter value. We also discu ss how envelope properties of the Sun depend on screening, too. We conclude that the solar model can be used to help settling the on-going dispute abo ut the "correct" screening factors.