70% of companies in the U.S. now allow at least some telecommuting, according to a recent study.  And working from home is mostly great, because you can stay in your underwear all day, and don't have to fight traffic.

But it also has its drawbacks.  Here are five hidden costs of working from home . . .

You socialize less.  It's really easy to never leave the house or see another human being for days on end.  Which can take a toll on your mental health.

Out-of-pocket costs.  You spend more on utilities like heating and air conditioning, because you're home all day.  And things like computer and printing costs add up.  It's hard to complain when you don't have to buy work clothes or pay for gas though.

The potential for higher insurance costs.  This one doesn't apply to most people who work from home.  But some people have to add more insurance to cover business equipment.  And if clients come to your house, you might need extra liability insurance.

No separation between your work life and home life.  It can start to feel like you're constantly at work.  And a lot of people who telecommute tend to work longer hours.  So it can really mess with your work-life balance.

It's tough to climb the ladder.  A 2014 study at Stanford found working from home lowers promotion rates by 50%.  Your boss is more likely to promote someone they see regularly, even if they're less deserving.

U.S. News & World Report