First built as a home, it was used as a boarding house as early as the 1920s. During World War II, it was used as an officers' club for American medical officers from the US base hospital over the road, now the site of Dilworth Junior School, a neighbour that provides Aachen House with the guarantee of unspoiled views to the south.
The McKirdy's additions have upgraded the accommodation from seven small guest rooms, with a couple of shared toilets and showers, to eight bedrooms, all with ample en suite provisions. But the key addition is the large conservatory overlooking the garden, which provides an elegant dining room and opens the house to light.
There is also a pleasant gazebo, described as "a tea house", which makes a nice setting to lounge away an hour's reading time and there's a charm in learning the history of the house, a story traced in detail by the McKirdys although, oddly, there is no definitive answer to how the house acquired the name Aachen. The German town title appears to have been a comparatively late arrival, some time before the mid-1950s.
That the development of the fabric has remained so in character with the period of the building reflects the McKirdy's fascination with antiques and the property serves as a giant display setting for their remarkable collection, particularly of porcelain.
The collection was amassed over more than 20 years overseas and filled three containers to be brought home to New Zealand.
If your interest inclines that way, you can spend hours browsing the display cabinets and, even if you are less fascinated, the collection provides a pleasing setting for the comfortable guests' lounge.
If the Aachen house collection sparks your enthusiasm for retro, you're in the right place, with the antique shops of Great South Road and Remuera within easy reach. Joan is still collecting locally and has the eye to pick the worthwhile, I'm more inclined to carefully select the bogus and totally naff from the genuine but it's still an appropriate way to poke about the neighbourhood.
We actually started our visit with an outdoor rather than domestic setting, ambling up the path round the corner which leads to the top of Mount Hobson. The remarkable panoramic views from here are breathtaking and, for the out-of-town visitor, provide a matchless opportunity to sort out the lie of the land in Auckland.
With a train station and link buses to hand, it's easy to get to the city and to the shopping and restaurant meccas of Parnell and Newmarket, so easy that guests are advised not to bother picking up their hire cars at first because they can hit the Auckland shops and restaurants without being instantly appalled by our interesting driving behaviour. And if public transport is too much of a challenge, the Remuera restaurant centre is within a few moments' stroll.
But if the setting and accommodation are attractive, the most distinctive quality of Aachen House for us was the service and attention to detail. Joan McKirdy is the prevailing spirit of the house in more ways than one. The standards are set high. The beds are huge and comfortable, the linen and furnishings are of the best and even the bottled water is the brand for which, according to the Daily Telegraph, Claridges in London charges £50 ($124) a litre.
Her staff are models of discreet efficiency and, in the rare event of your needs not being anticipated, there's an air of complete confidence that any requests can be quickly met. It is not surprising that, in 2005, Aachen House captured the title of leading boutique hotel in Australasia; a competition decided by the opinions of guests.
Our stay was too brief and we left after an excellent breakfast, thinking how welcoming Aachen House must be for those tourists and business guests who want to treat themselves to comfort and style but want something more intimate and relaxed than the big hotel - a home away from home - although perhaps rather more lavish than the average domestic establishment.
We were also thinking that it's too good to waste entirely on our foreign visitors and that here's an opportunity for New Zealanders looking for a treat too.
* Aachen House is at 39 Market Rd, Remuera. Phone: (09) 520 2329.