Heater for room

So my bf and I are having a debate on whether or not to turn the heater on. I don’t feel comfortable because I know it can increase SIDS but I also understand that it has been getting cold lately. I don’t know the exact temperature of our room but the app shows 59 degrees right now and 54 at its lowest. Im currently dressing the baby is a long sleeve onesie, a regular onesie and footie pajamas and socks. Should I put more clothes on him? Turn on the heater? We honestly are freezing in the early mornings but idk if a heater is safe or not

edit to add: i have a clock with a temperature and it says 73 but I’m not sure if it’s accurate because the house does feel cold already. Does anyone know how I can take the temperature of the room?