Stretching is a natural characteristic of new vinyl and as such, during initial use, the air bed may become soft and require additional inflation to maintain the desired firmness. This is normal for the first few uses. Please make sure the valve is fully sealed (OFF position). The ambient temperatures of air have an effect on the air bed's internal pressure. At low ambient temperatures, the air will contract within the air bed and the air bed will feel softer. Add more air as necessary. If it continues to deflate, please contact our Customer Care Team here, so they can help you with this. Please read your instruction manual for some causes and solutions to air bed deflation.