stinky nursery! help!

my son is 1 years old, we have a diaper pile and we change it once it’s full usually every other day. lately his poops have been starting to stink, so the entire room is stinky. we use febreez and candle warmers.. but still. it’s embarrassing to have people come upstairs and at night the smell keeps me up at night even with door closed. also it’s winter and freezing so we can’t leave the window open like we normally do.

what else can we do?