Recommendations on Sleep Sacks/ Wearable Blankets?

Can't you just double up? When I was a kid and nights were cold I usually wore tights under my pajamas or nightgown. Sometimes socks too. Just dress him in more layers.

Put on pajamas and a blanket sleeper. Carters sells them. They are one piece footed sleepers. Just make sure PJs go under it

If the heat is set at 74, how is the temp in that one room dropping to 62? If the heat duct isn't working or blowing properly, perhaps addressing that vs. plugging space heater into potentially old electrical outlets is a better option. My house is well over 100 yrs old, so I get that some rooms just don't heat up as well as others, but I would be REALLY uncomfortable leaving a plugged in heat source on in an infant's room. "Nursery friendly" or no.

Sometimes in the winter, we have to leave certain doors open and other ones closed in order to get the best/most even temperature outcome.

Sleeping in quite cool temperatures isn't going to hurt a baby as long as they are dressed for it. The bigger worry is a diaper leaking - creating a pretty chilly situation, but baby should wake you if they are cold and wet.

Before putting a plugged in heat source in a nursery, please visit your local fire department and get their input. You might find it is better to move baby to a warmer room or heat the room PRIOR to baby going to bed and unplugging the heater and then shutting the door to trap the warmth.

Good luck.

Do you have the ones with sleeves? As Patty mentioned they are made by Carter's and I LOVED them. My kids seriously lived in these things and I had a bunch of them. Target sometimes sells them or Carter's stores starts carrying them around now. I usually had my kids in at least a onsie inside of it but sometimes more or sometimes just a diaper. They are very cozy. I didn't use blankets with my kids until they were a year old.

When my oldest was tiny we lived in an old farm house in England and it was very cold at times, I would put his regular PJs on under a sleep sack and then swaddle him to help keep him warm. A nursery safe heater is a wonderful idea.

How old is your son?
Wearable blankets come in all sizes for all ages.
Google it and you'll get tons of info.
While the recommendation from most sources says a room should be between 68 and 72,
some places have babies bundled up and napping outside in 20 degree weather.

"The babies who nap in sub-zero temperatures"
http://www.bbc.com/news/magazine-21537988

As long as he's dressed for it, the room temp shouldn't be a problem.

We always used Halo Sleep Sacks (this was years ago) but they were great. We have very cold winters, and our first house was a very old house like yours.

They have a 'winter' variety - blanket thickness. Here's the link (it's safe - I've been a member here quite a while)

https://www.toysrus.com/product?productId=63012346

Or type in to the babiesrus.com site -

HALO SleepSack Wearable Blanket Winter Weight - Blue Penguin

It says: With a TOG value of 2.5 and a cozy quilted feel, the SleepSack Winter Weight is our warmest wearable blanket, ideal for the coldest of winter nights.

Added: I always did the onesie, then thick fleece sleeper, then the thicker winter variety bag.

you could always double up the sleep sacks, there was a cold night long ago when my now 7 yr old was a toddler. we had no power at bedtime so i put him in a fleecy footed sleeper, and put a fleecy footed sleep sack on top of that. he was warm and snuggly all night. (when the power returned i did remove the extra layer so as not to cook my kid)
the house temp was sitting at 63 ish when we all went to bed