A friend has a big log cabin out in the country that is swarming with ladybugs. So far he’s vacuuming them up as much as he can. If you, readers, have ever had your house invaded by ladybugs, what did you do? Did the ladybugs eventually die off? Did you spray insect killer around? We hate the idea of killing such a pretty and beneficial critter, but we don’t like a truckload of them crawling and flying around our living quarters, either. Advice?
My guess is that it’s the “Asian ladybug” since those swarm into houses in colder weather - orange rather than red, biter, can spray a stinky, staining fluid. They can be beneficial to pest control outside but are a pain in the butt to humans in this respect.
Best bet at fighting them long-term is sealing all the cracks that they’re using to get in - my inlaws had to do that when their house addition got swarmed into - but the Wiki article I linked has some methods of control at the bottom as well.
Here is a handy-dandy fact sheet.
It has a link to instructions for building a trap.
If you suck them up, put a knee-hi stocking over the end of your vacuum cleaner wand so they don’t get sucked through the impeller and chopped up. They are very smelly when squashed.
This happened in my office one time years ago.
We just used a dustbuster every morning to suck them up and let them go outside.
Did this for over a week, but got most of them, and it never recurred.
I hate to think of killing an entire ladybug generation in our area for several reasons.
Just get a dustbuster and practice catch and release!
They eventually move out in the spring. In the mean time they become active on warm sunny days. I sucked them up with a vacuum when I had a thousand or so at a time to deal with. That’s not exaggerating. During times when they are out in small numbers I use duct tape and stick them to it like fly paper in the middle. I then fold the tape in half trapping them inside. This way I do not have to deal with that horrible smell.
They can squeeze into the narrowest cracks so keeping them out is almost impossible. A quarter inch long gap of missing caulk at a joint is going to let them in.
Vacuuming seems to be the best thing. When they want to move out in the spring, what, should he open his doors and windows? Do ladybugs stay around and come back into his house in the fall, year after year, or could this be just a one time thing?
I don’t know if they live long enough to come back in the fall. The offspring definitely do come back, so any cracks you can seal up will help. I also notice they go for things painted white on a sunny fall day.
First you get some bug-eating lizards. After the ladybugs are gone, you import some Chinese needle snakes. To get rid of the snakes, you can get a few gorillas that thrive on snake meat. Then just wait until next winter and the gorillas will simply freeze to death 
they will survive a ride into a house canister vacuum. if you don’t want them alive and still inside your house then you have to take the vacuum out and empty it. a strong shop vacuum with lots of power and turbulence will kill them.
in their native habitat they look for nooks in vertical surfaces facing sun exposure to winter in, so crawling into small openings on warm late autumn days is what they do to survive. they eat aphids which die after a freeze so when they stop eating they look to seek a winter site to bed down in.