I moved from the US to Germany 2 years ago. Here are the 7 biggest culture shocks I've experienced.

After a tiring seven-hour flight from Boston to Frankfurt, a three-hour drive from the airport, and six flights of stairs to our apartment, we arrived in Düsseldorf and quickly learned air conditioning isn't really a thing in Germany.

The large tilt-and-turn windows in our place didn't have screens, only metal rolling shutters. This meant we couldn't open the windows fully for fear our cats would try to go outside.

Instead, we cranked the metal shutters down early in the morning to keep hot air out and then rolled them up at night to allow cool air in.

We also stayed hydrated, added ice cubes to the cats' water bowls, tried not to use the oven, took cool showers, and ordered a standing fan.

It blew my mind to learn that only about one in eight German households use air conditioning. Still, we had no choice but to adjust to that lifestyle.

Growing up in the Massachusetts suburbs, I relied on my car and only used the train to commute to Boston. Although I have a German driver's license now, I haven't driven in the last two years.

My husband and I have moved to a few different cities within Germany, and luckily, we've always had easy access to public transportation.

We landed in Germany on a Sunday and soon learned that most shops — even grocery stores — were closed, forcing us to use a food-delivery app.

That's because Sundays are rest days in Germany. Most people aren't supposed to work or shop, though there are a few exceptions for touristy spots and gas stations.

When I was apartment hunting, I was surprised to learn that many rentals didn't have kitchens stocked with a refrigerator, oven, cabinets, counters, washing machine, or dishwasher. Instead, there was typically only an empty room with appliance hookups.

That's because, in Germany, tenants often take most of their kitchen with them when they leave, or they sell the major parts to whoever is moving in. This allows tenants to personalize their spaces, can help landlords save on costs, and may encourage tenants to stay longer.

To avoid fees and security concerns, many restaurants, local businesses, market stalls, and cafés only accept cash as payment.

Luckily, many larger businesses, grocery stores, and malls accept credit and debit cards, as well as other forms of digital payment.

In Germany, tipping is appreciated but not expected.

At restaurants, it isn't common to add a tip to the receipt. Instead, people will leave a few euros on the table as a thank you.

The first time I went to pay at a hair salon, I was prepared to give a 20% tip. However, the stylist explained that while she appreciated the gesture, a 5% to 10% tip is typical. She also said some salons don't process tips by card, so cash is preferred.

In Germany, restaurants automatically serve sparkling water without ice. If a customer asks for ice in their water, it clearly signals that they're American.