Well, I live in Oklahoma and if it's 65 outside I'm okay with that. If it's 65 inside and it's night time I'm not okay with that. I won't sleep well. I like to have a comfortable temp while I sleep.
I think it's up to you to have your house what is comfortable for you. You know people don't go by that stuff don't you? If you want the house 65 degrees then I think that's way too cool for anyone. My opinion.
I want my house about 70-71 at night. I can sleep without a ton of blankets and if I wake up to go pee I am not shaking with cold. I am comfortable enough to get up and go quickly.
So, if you go ahead and decide that 65 degrees is comfortable for you I suggest you do not pack your baby up in sleepers and blankets. Why? They are going to be covered in sweat and can easily get their faces covered up and suffocate.
There is no way I'd make the house any cooler than where my kiddo can sleep in a normal onsie with feet and where they can move around when they're a little older.
One thing, how are you going to get your house down to 65 in the heat of summer? If "that's" the proper temp for babies then that goes year round, right? It's not just a "Don't heat your house in winter but make it hot in summer" sort of thing, if it's the "best" temp for babies then you might want to start saving now so that you can pay that high electric bill next summer. It's down right hard to get a house that cool in summer.