Holiday rentals and home sharing have become big business as home owners look to increase their incomes by renting and/or being hosts. The sharing economy, as it is known, is facilitated by technology-based platforms which means all you need is a computer and to be organised to get started.

At last month's The Irish Times "Home and Design" theatre at the Ideal Homes Exhibition, one of the most popular sessions was when Airbnb host Karen O'Rourke talked about her business and how she set it up. Questions flew and it was obvious that it is a subject of interest to many. If you have a holiday home or a spare room, what are the options for making extra money?

Technology is the key to making this business work. The company you may choose to use is a technology platform that will host your web pages and charge you a fee or commission on bookings. They are hosting your shop front but it is down to you to make it as attractive as possible. The level of assistance you receive will vary from company to company.

Homeaway has been around since 2005 and, through acquisitions such as Holiday-Rentals.co.uk, VRBO.com, Fe.Wo-direckt.de and Ownersdirect. com, grew quickly. Last year, it was acquired by Expedia for €3.9 billion and now hosts 1.2 million properties in 193 countries with 2,918 in Ireland. Expedia is the parent company of Hotels. com, Trivago, Hotwire, Venere and others – a big travel industry player.

This site specialises in whole home rental – no sharing. Originally it could have been described as a classified advertising site, where you were paying to advertise your property to rent and the cost was an annual subscription. Homeaway charges either a flat fee from around €300 per year or a commission of 8 per cent to owners and 6 per cent to guests.

Starting in July 2013 in Ireland, Homestay. com has already added 50,000 homes in 150 countries to its home-sharing site. Hosts welcome guests into their homes and usually provide bed, breakfast and/or cooking facilities.

Hosts and guests

Hosts set up a page about their home with photographs, a description and the interests of the family. There is an option to video call guests from the site and it is recommended to use it to get to know people before they arrive. Hosts can put up as many rooms as they have available for as many nights as they wish. There are over 1,000 hosts in Ireland. Homestay charges guests 15 per cent and the balance is paid directly to the hosts by the guests.

Last Saturday, Airbnb invited some of the many Irish hosts to their new offices, the Dublin Warehouse on Hanover Quay, for an open day. Sessions covered on the day included preparing your home, design, tax advice and managing your business. There are 11,000 hosts in Ireland and Airbnb probably goes the furthest in helping people get their homes ready and market them. All communications between hosts and guests are through the website. All payments are taken from guests at time of booking and disbursed to hosts 24 hours after arrival of guests, assuming no issues. Airbnb charges hosts 3 per cent and guests 6-12 per cent.

All these sites verify owners, hosts and guests, whether by scanning a government-approved ID or using a third party to verify your location and home, or indeed sending a photographer. The trust also depends on reviews. Owners and guests are expected to review each other, and bookings will be made based on their quality.

Tripadvisor Holiday Rentals have 770,000 properties available through its site. OnefineStay.com, which specialises in very high-end properties, was purchased by French Accor Hotels for $170 million last month. Wimdu, 9Flats, Perfectplaces, and Rentalia are other similar rental platforms for hosts.

Tax implications

While these websites are all worth millions and billions of dollars, it is interesting to note they do not own any properties – your home is their bricks and mortar. Income generated for home rentals is subject to income tax less some costs of managing your business. It is recommended you keep all receipts, bank records and use an accountant to help file returns.

A castle stay: Galway dream option

You can never underestimate the attraction of staying in a castle. Peter Hayes, owner of Caherkinmonwee Castle near Craughwell in east Galway, found that out very quickly when he listed his property on Airbnb. In fact it was a friend who was trying to help who listed it for him. His dream of restoring the ivy-imprisoned ruin to its 1400s glory was fast disappearing with his funds. After 12 years of relentless work, the castle was almost, but not quite restored, and Hayes put it on the market.

There was some interest but no sign of a buyer. The castle had been listed on Airbnb for some months but he had ignored all requests for bookings.

One day in January 2013, he stopped to look and count what the bookings he had turned away would have meant.

That was when he realised that people really did want to stay in his castle and maybe this could be the way to hold on to it. Hayes and his partner, Eva, got down to work and transformed the top two floors into a very comfortable and cosy lair for visitors. His castle has more than 470 five-star reviews on Airbnb and is busy all the time; the calendar is booked virtually every night until October. Guests are happy to pay €130 per night for the pleasure of climbing the winding stone staircase for a night under the battlements. “I want to finish my dream and Airbnb is helping me get there,” says Hayes.