Terraced back-to-back two-bedroom houses currently for sale in St Raphael's Manor, Celbridge, Co Kildare, are compact, neatly-designed homes with 835 sq ft of space. A small glazed porch opens directly into a large livingroom, which has an attractive slate fireplace with timber surround, and coved ceilings as standard. To the left is the kitchen, with an eating area beside the front window of the house.

Up a steep flight of stairs, there are two double bedrooms, both with built-in wardrobes, and a good-sized bathroom with both a bath and a separate shower and a very high Velux window. There is tongued and grooved timber flooring upstairs.

Each house has a small landscaped garden area at the front, enclosed by a brick wall, a communal landscaped open space with each terrace, and a space for parking. Mid-terrace houses in the scheme, being sold through Billy O'Sullivan & Associates, cost £96,950, end-of terrace houses, £99,950.

Twenty-eight of the 169 houses in phase one of the St Raphael's scheme, launched nearly two years ago, were two-beds (they cost £72,000 at the time); there were no two-beds in phase two, but nearly all of the 150 houses being built in the current phase three are two-beds.

There has been major interest in the two-beds since they were first launched, says O'Sullivan, and no consumer resistance to the back-to-back house style which means, for example, that mid-terrace houses have windows only at the front, with a couple of deep Velux roof windows inside. (The end-of-terrace houses have windows at the side as well.) And they are certainly holding their value: Douglas Newman Good recently sold one of the original end-of-terrace homes near the showhouse for £95,000, with the sale agreed within a week of the property coming on the market. There are eight two-beds left for sale in this phase, costing £96,0950 and £99,950.

St Raphael's Manor is just minutes from Celbridge, Co Kildare, an attractive village with a wide main street running up to the entrance to Castletown House. The area is still the countryside, despite the encroaching suburbs, and this is one of its chief attractions. There is an Arrow station not far away, and good peak-hour train service; Dublin's city centre is about 45-minutes drive away.

The two-beds in the St Raphael's development are similar in price to two-beds for sale in the Castle Riada development in Lucan, where mid-terrace two-beds cost £98,950, and end-of-terrace two-beds, £101,450. These have 770 or 840-sq-ft of space, depending on whether they have extended kitchens. They are not back-to-back, and have reasonably-sized back gardens. There are just two 770-sq-ft mid-terrace houses for £98,950 left for sale, through Hamilton Osborne King. 28 out of the total of 250 houses in the Castle Riada scheme are two-beds.

The livingroom at the front of the Castle Riada two-bed house is divided from the good-sized kitchen/diningroom at the rear by a glazed timber door. Patio doors open into the back garden. There are two windows in the main bedroom at the front of the house, upstairs; both it and the rear bedroom are reasonably-sized doubles. There are polished timber floors in the showhouse (those these are not standard) and the houses feel bright and spacious.

Castle Riada is one of the estates in "new Lucan", the sprawl of suburban developments on the opposite side of the dual carriageway from Lucan village, where thousands of houses are being built. The area is a tangle of new roads and new houses, some built, many still under construction - get good directions to Castle Riada, which has no billboards announcing its presence like other developments in the area.

There is definitely a growing demand for two-bed houses, according to agents, whether they are old or infill houses within a three-mile radius of the city centre, or in new suburban developments where until recently, the basic house was the three-bed semi. Most, although not all, of it is coming from first-time buyers, mostly couples and some singles, looking for a house that is cheaper than the three-bed, as well as being more easily maintained. Separating and divorcing couples are also in the market for a smaller home, as well as older couples trading down - although it seems many of these want either apartments, or bungalows, with an eye to their advancing years.

Billy O'Sullivan says that after he sold the first 28 two-beds in St Raphael's Manor, he got many phone calls from young buyers asking if they were building more. Declan King of Gunnes in Lucan says that semi-detached two-bed bungalows and two-storey houses built a few years ago in his area now cost from the mid-£90,000s to over £100,000. Gerry Leahy of Leahy Property Consultants has been selling two-beds in Ballydowd, a Lucan development next to Castle Riada, but believes they are not yet an established part of the suburban mix.

Up until now, there have been quite a few two-beds built, but mainly in expensive, upmarket developments where they are called "townhouses". When is a two-bed a two-bed and when is it a townhouse? Keith Lowe of Douglas Newman Good explains "If you're looking at a mixed scheme of two, three and four-beds, then it's a two-bed; if you're looking at a mixed scheme of apartments and houses, then the two-beds are called townhouses."

And although affordability is considered one of the chief attraction of two-beds, price, as always, depends on location: there is strong demand, for example, for back-to-back terraced two-beds in St Augustine's in Blackrock, Co Dublin, costing around £160,000. Two-bed townhouses in an upmarket riverside apartment/townhouse development near Lucan village sell for around £140,000.

Most agents are convinced that once new housing densities have been established, there will be a great many more two-beds of various sorts built, believing, as one agent says, they are perfect homes for the first-time buyer. Says Lowe "In new schemes, we'll see a lot more two, three and four-storey apartment blocks and back-to-back townhouse developments."

Sean Mason of Mason Estates reports that there is huge first-time buyer demand for two-beds - both old and newly-built - in a three-mile radius of Dublin's city centre. And he believes "without question that people prefer houses to apartments. Young Irish buyers view apartments as a stopgap for two or three years."

This is where the two-bed comes into its own: a back-to-back two-bed, for example, might seem a little claustrophobic to someone used to the more traditional three-bed semi, on first viewing. The idea, says Keith Lowe, is to look at them as an alternative to apartments, rather than as houses - with the advantage of having a home on two levels, with your own front door. He believes the market for these properties will be first-time buyers and divorcing couples, with retiring people looking for apartments. One man who lives in an upmarket two-bed says that even couples who have one child are tending to stay on in their two-bed houses.

Government decisions on housing densities as well as builder economics and consumer demand will determine what happens from now on. But the future includes two-bed houses, and many young first-time buyers are voting with their deposits for them.