Small outdoor structure to keep house plants warm in winter?

I have various house plants that I need to move outside for the winter.I also need to keep the plants above 60*F.Most of them do best in indirect sunlight and wilt really badly below 60*F.How could I make a cheap quick shelter for these plants and keep them warm?The biggest one is 3 feet tall.The shortest one is about a foot tall but has 20 foot runners/vines.This plant with the long runners/vines is fairly old.I have five plants in total,that takes up a wall space about 6 foot tall and 10 foot wide.Most of my plants are old, and were handed down to me by my grandmother, about 10 years before her passing.So, I want to take exceptional care of them while we are doing some home renovations.Once I get my out buildings in place and set up,I maybe able to move them in there and add a window to let in light.I just don't know when I will be able to move the buildings in.

Do you have a friend that will plant sit?

How much money are you willing to spend?

You could get a little greenhouse, a couple black rainbarrels, and an electric water heater (like for large aquariums).

Google cold frames and hot frames. Dig a hole, line it with black stuff. Build a small shelter frame out of foamboard or straw bale. Get a shower door from CL or habitat re-store to make the window-$5. Add a small heater or lamp if you need extra heat (taking extreme care not to burn anything down).

It's difficult in our climate to guarantee that you can keep the small outdoor structure above 60F. I have a wood-framed greenhouse with 4 mil plastic sheeting and it keeps the plants from freezing, but it won't keep the turmeric (which probably falls into that above 60F class) going.

It's not every day that drops below 60 in the greenhouse, a lot of winter days it gets downright hot in there and I have to keep the door open to get some more ventilation. It's those clear, cold days after a front comes through when it drops into the 20s at night and the next day only gets up to 50 that are the worst. Then I am filling all the buckets I have and putting them in the greenhouse to increase the thermal mass.

If you want to keep your small structure above 60, I think you are going to have to have an additional heat source for those times. If you put a 30 or 50 gallon fish tank inside the structure and have heaters in it that keep the water at 75F, then maybe the air temperature inside will stay above 60.