Using a randomized field experiment in the Swedish pension system, we investigate whether receiving an information letter affects the take-up rate of the housing allowance for pensioners. We also investigate whether the framing of the information letter affects take-up. The results show that simple information letters had a dramatic effect on the application rate and subsequent take-up rate: the baseline application rate in the targeted control population was only 1.4 percent while the corresponding rates in the different treatment groups were between 9.9 and 12.1 percent. The letter that addressed common misconceptions about the benefit caused significantly higher submission and acceptance rates. The letters had a substantial economic effect on the applicants. We estimate that the applicants, induced by the treatment, increased their monthly income by around 10 percent.