The size of the house will greatly influence the running costs and warrants a thorough deliberation at the outset, as the temptation can be to build as big a house as you can afford, as opposed to building one that meets your needs and that you can afford to run. In this regard, it is vital that you sit down with your building surveyor or architect or whomever is designing your house at the outset to develop a clear and well-thought-out brief.
Running costs, which are influenced by what you physically build (as opposed to property taxes, which can be more influenced by where you build), primarily relate to energy efficiency.
The building regulations set out minimum requirements and there are a number of useful internet sites with helpful tips on, for example, increasing insulation, using solar and alternative energy sources and the benefits of highly energy efficient boilers or fitting.
The Sustainable Energy Authority of Ireland’s site (www.seai.ie) has a very useful guide on building an energy-efficient home (iti.ms/X87Brn), which also references other more detailed guides.
It is important not to overlook the building fabric and finishes, which can have a significant impact on air tightness and general maintenance and upkeep. For example, a brick-faced external wall needs significantly less maintenance than a rendered wall, which needs re-painting at regular intervals.
Ultimately, you should ask your designer to advise on the various options specific to your house, and their extra construction costs and estimated payback periods. A qualified professional should be able to provide you with a detailed report on lifecycle payback calculations, energy consumption and carbon savings, so that you can make an informed decision.