Dr Stirling Howieson at the University of Strathclyde is interested in numbers. From understanding the ‘big bang’ to managing your credit card repayments, numbers hold the key to everything. Here in his regular column, he offers some more interesting figures…

80- 200m² Pigs, Pokes and Horses Some 18 years ago, the Royal Incorporation of Architects in Scotland organised a competition encouraging architects to engage with the speculative volume housing market. Branded the “House for the 90s”, the conditions were unusually detailed, prescribing a maximum floor area of 80m². Many architects viewed such a brief as a ‘prize pig’ competition. It is difficult to get ‘Grand Designs’ into such a small poke.

Undeterred I fed and groomed a small sow for several months. Super insulation (U value 0.1W/m²OC) enveloping a large thermal mass using hygroscopic materials and heat recovery ventilation, produced a dwelling that did not need a heating system and met the recent Scottish Government’s target for an 80% reduction in CO2 emissions. I presented the drawings with a touchingly naïve degree of satisfaction and expectation. You may be able to imagine my disappointment when the prizes were awarded to three horses – dwellings with floor areas between 175 and 200m²?

Now I would be the first one to agree that in the aesthetic and racing stakes a horse is much prettier and faster than a pig, but the rules were mandatory; this was a ‘pigfest”! My intemperate enquiry into this bizarre outcome was rebuffed by no less than the Secretary of the RIAS; the pharisees that formed the judging panel, “do not like pigs” and that was that!

The recent Highland Housing Expo, billed as “52 fantastic houses designed with the future in mind” raised my expectations that, at last, Scottish architects were addressing the requirement for affordable and utilitarian low carbon dwellings that don’t expose their occupants to toxic gasses or house dust mite allergens.

Alas it proved difficult to evaluate these dwelling types as the pig/horse quandary was once again evident. If we had been furnished with the build costs or asking price, some crude cost/benefit evaluation would have been possible, but with no such information made available and floor areas ranging from 79 to 169m² what was Joe Public to make of this?

Some performance data was published, but in the main, these numbers suggested that the dwellings are about 20 years behind current thinking. Low carbon dwellings should not require 30kW gas boilers – a recurrent feature of those dwellings that were actually finished on time for the Expo opening. Only one of the dwellings came close to meeting what is cost effectively possible, with a total annual heating requirement of circa 1500 kWh. This compared with 17,236 kWh for the most energy profligate design(producing a whopping 8.7 tonnes of CO2 per annum for space heating alone). And therein lays the crux of the matter.

Despite a growing realisation regarding the importance of meeting reduced carbon targets by improving fabric and system performance, almost all of these “award winning” architects were happy to design dwellings where aesthetic juxtapositions (NB: if you wish to get serious about architecture you learn early in your career to express the complexity of your cerebral gymnastics using incomprehensible and florid gobbledegook) took up 40% of the internal volume.

Another worryingly encapsulated the internal volume in an impermeable layer of synthetic black rubber and had the audacity to claim that it was a, “sustainable solar thermal absorber” (unfortunately on the wrong side of the insulation layer and shortly to be covered with ivy!) demonstrating a breathtaking ignorance of standard grade physics.

So if you are an individual with no possessions, only one change of clothing, wish to spend your life reading by the light of a flickering mercury filled fluorescent lamp inside a black rubber poke, properties are now available! Horses may be pretty, but when compared with the noble and intelligent pig, they appear -like many of these Expo dwellings – to be somewhat dim and consume far too much hay.