A blown air heating system has a housing having an upstream air inlet and a downstream air outlet and a forced-air device configured to draw air into the housing via the air inlet and force the air out of the housing via the air outlet, wherein the air follows an airflow path from the air inlet to the air outlet. A gas burner is configured to heat the air as it passes through the housing. A gas valve is configured to provide a fuel gas to the gas burner, and the gas valve is located between the air inlet and the air outlet and in the airflow path. A baffle is in the airflow path, and the baffle is configured to divert the flow of air away from at least part of the gas valve.