First off, petunias and heliotrope are perennials. If they were annuals, they would die after forming seeds and no amount of coddling would get them through the winter. I doubt your baskets are worth trying to overwinter, especially the petunias. I've tried both (not the petunias on purpose, but because they were in the container with something I was saving), and neither survived. It's difficult some years for us to get heliotrope--it seems to go in and out of favor, so I have tried it, but it was just too dry in my house for it. I'm not positive, but I think heliotrope has a minimum temp. of less than 45 degrees. Actually, now that I think of it, I have certainly put it out when the temp was between 40 and 45 at night, so I know it can survive that.
By the way, I am assuming you mean H. arborescens, the common garden heliotrope.

just give it a try ...

presume failure.. and be mildly surprised if you succeed ...

the problem is often the media .. the plants in hanging baskets fill the media with roots ... and then the media starts breaking down.. and it loses its drainage abilities.. and you can get root rots ...

and then there is the lack of 'good' light thru windows.. leading to reduced vigor ...

and then there is the lack of humidity in a house in winter in z5.. especially with a forced air furnace ...

then there might be the bugs you bring in the house with the pot ....

then there is the fungus gnats .. caused by media that doesnt drain properly .. and the media being too damp ..

been there .. done that .. loved it while i had fun .. AS YOU SHOULD ... but eventually gave up as it wasnt worth the problems ...

give it a go ... experimenting is the fun part ...

ken

I know that petunias are very cold hardy and I think that heliotrope might be, too. I don't have the experience with the latter. Petunias can take frosts and even light freezes, making them quite popular in warmer climates for late fall and winter plantings.

However, both will be quite unhappy inside. You cannot duplicate the outdoor sunlight and humidity that these plants require...at least not without some effort and a few purchases.

Both of these plants perform best in the category of 'perennials used AS annuals' because they lose so much vigor by the end of their flowering months and because they are quite inexpensive to purchase as brand new youngsters in the spring. Ken lists, very well, some of the other challenges that you would face.

BUT, I agree that nothing beats first hand experience when it comes to gardening endeavors. "Give it a try." You might nurse your plants through the winter and be well pleased if they make it!

If you have small children and pets, please do some careful research about heliotrope, in particular.

If you decide to give it a go, as ken puts it, let us know and we might be able to go into more detail about some steps you can take to swing the odds in your favor.