It's somewhere between a holiday rental and a boutique hotel. It's not cheap but it can be a seen as a bargain. And in the fluctuating real estate market, it has become a hit for hesitant home buyers. Say hello to the extended-stay, luxury apartment hotel that is taking the world by storm, from Berlin to Beverly Hills, New York City to London.

Aiming to woo highbrow travellers who require more than a week in the destination they're visiting, apartment hotels provide the luxury of a spacious, well-designed apartment with the added benefits of top notch amenities, such as concierge service, daily housekeeping, dining facilities and business and fitness centres.

But it’s not just travellers who are booking. With the fluctuating US real estate market, many cautious second home buyers are spending their holidays in extended stay bookings, according to the Wall Street Journal.

The best known extended-stay apartment hotel is AKA, which has nine locations in key markets throughout the US, including Philadelphia, Washington DC, Virginia and four in New York. The company, launched in 2005, is recognised for having the style and hospitality of an intimate hotel with more offerings than a vacation rental, including 24-hour room service, concierge, housekeeping and, depending on the location, parking.

According to company president Larry Korman, “AKA fulfils a need among an increasingly nomadic culture of upscale consumers who have to be – or want to be – in one place for more than one week, whether it’s for business, a home renovation, a job relocation, a divorce, or the desire for change.”

AKA Beverly Hills, opened in March 2013, has 88 one- and two-bedroom residences with kitchens, private balconies, fireplaces and free wi-fi. Residents also have private access to Spago, Wolfgang Puck's iconic restaurant, located behind the building, and the added perk of ordering room service from the restaurant’s menu.

The value of an extended stay luxury apartment hotel can be extraordinary. Guests at AKA Beverly Hills can expect to pay around $400 a night for a 1,055sqft one-bedroom deluxe suite. This is comparable to the size of the Peninsula Beverly Hills' California Suite, a space that starts at $2,000 per night. Furthermore, stays at AKA include bicycle usage, local telephone calls, private parking, on-site laundry, business centre services and use of the executive boardroom, all of which are complimentary.

December 2012’s opening of the independently owned Residenza San Lorenzo added to the trend by offering accommodation from one week to one month in the historic California city of Palm Springs. The boutique hotel has eight one- and two-bedroom apartments, a large pool, spa, courtyard and sun decks. Complimentary services include laundry, parking, concierge and airport transportation. Interestingly, several of the rooms are partly or unfurnished, giving guests the liberty to create their own interior or have it furnished by the hotel's designer.

The trend has also spread to Europe. AKA London, opened in October 2012, is the first international property for the brand. Located in the Marylebone neighbourhood, the boutique property has only nine suites, each with bespoke furniture, kitchens and full marble baths, while the property’s two-bedroom, two-bathroom home includes a study and a private garage.

Soho House Berlin is housed inside a former 1928 department store in the Mitte District. Opened May 2010, the property allocated 20 out of 85 rooms as fully furnished, extended stay apartments, a first for the Soho House brand. All residents, both in the apartments and the hotel, have access to the Cowshed Spa and gym, rooftop pool, Cookhouse restaurant, House Tonic bar and a screening room, but the apartments offer extra amenities such as grocery delivery and a fully stocked kitchen, as well as reduced rates for longer stays.