Building’s Performance in Use

Sunny Bank, Inkberrow

The gross internal area of the building is 525 square metres.

The building has yet to be occupied for a full 12 month period, so costs in use cannot be fully determined on a cost per annum basis without involving hypothetical statistical extrapolation.

Comprehensive measures have however been taken to reduce the energy use of the house from the point of design inception onwards. Given the vast expanse of landscaping to the rear, there was an ideal oppotunity for a ground source heat pump to be installed which was  also naturally suited to the early decision to include a subscreed wet underfloor heating system to both the ground floor and first floor levels, the lower ambient heat generated by such a system being ideal for underfloor heating, but otherwise dictating oversized conventional radiators. The ground source pump was not commissioned satisfactorily until December of 2010 and the fact that it was running constantly until then will further have distorted any energy use calculations or billing information. The manufacurer of the system, Dimplex, are convinced that savings of an average 50% can potentially be made when operating compared to conventional heating costs. Bills to date, with conditions of commission in the adverse state they have been, are inferring total utility costs of approximately £1.25 per square foot per annum which is already encouraging when compared on a similar basis to conventional dwellings. The majority of this bill is for electricity which is now directing our Clients decision regarding the introduction of photovoltaic cells to supplement their draw from the national grid, but also offer feed in tarrif opportunities as the daytime demand on electricity between Monday and Friday is light.

On the roof of the garage block, solar collectors give a contribution to the domestic hot water demand which is also topped up from the ground source pump when sufficient spare capacity exists. During the summer months when spare capacity exists in both the ground source and solar collectors, it is designed such that this will be diverted to the swimming pool as a primary heat souce for the water during summer months.

Lighting within the dwelling comprises low efficacy elements and where possible is locally switched, whilst having overall comprehensive programable control using a Philips ‘Dynalite’ system which has potential to control sequences involving drawing the curtains, adjusting lighting levels and the playing of music for instance which on a timed setting offers enhanced security to the property.

The west elevation is predominantly glazed to take advantage of both the view and incident natural light, the downside of this being the potential for excessive solar gain in the afternoons. This is initially countered by the incorporation of solar control glazing, supplemented by the multi perforate abilty of the screens to this elevation being either folding sliding screens that open in their entirety, or paired sliding doors that reveal 50% of the entity of the screen. There can be no ‘greenhouse’ effect if the ability to remove the influence of the element that causes it exists whilst naturally ventilating the space at the same time. Added to that, the underfloor heating and ground source heat pump can be run in reverse thereby removing heat from the fabric, dumping it either in the ground for future use, or by warming the water within the pool. The swimming pool itself, acting as a reflecting pool, is close enough to the building to reflect light from is surface whilst taking some of the sun’s heat out directly.

The window frames are crafted from a fast growing, knot free, hardwood; Idigbo. Procured from sustainable sources, a low maintenance stain finish has been applied, this timber having an exceptionally high tannin content it has been discovered elsewhere that a paint finish will quickly detach itself from the face of the timber. This is part of the philosophy of using low maintenance materials throughout the palette; brick, stone sourced from site, acrylic render, timber framed windows, factory coated zinc flashings and roof elements and a single ply membrane to the roofs.

Most arisings from the build process were set aside for re-use or redistributed around the site, export from the site being de minimis. The use of local stone, effectively quarried on site, could not have ‘greener’ credentials. Where ever possible, labour and materials were from relatively local sources.

Incident rainwater is contained within the boundary of the site and percolation is delayed; a new balancing pond to the bottom of the field receives most of the rain, but an underground storage tank next to the house serves to facilitate grey water recycling to the WC cisterns and irrigating the garden areas within the residential curtilage. Our Clients are aware that it can also be used for washing machines, but they aren’t quite comfortable with that concept yet…. The level of water in the balancing pond has been observed to fluctuate by a relatively small margin thus far, meaning the semi-wetland created at its periphery is contributory in increasing bio diversity; a number of unusal visiting water fowl have already been spotted. The retention of the paddock field as meadow land also sustains and encourages biodiversity, particularly the attraction of insects which in turn encourages and sustains evening foraging for the already established the local bat population. Roosting accommodation has been provided for bats within the front loft space of the new dwelling to replace any potential roosts lost during the demolition of the existing buildings.

A gas supply has been brought into the building, to be used primarily for cooking, though it does also supply the two feature fireplaces; one within the two storey lounge area, the other in the snug. The snug being a separate and cellular room can be utilised when the family wish to withdraw from the general open plan; at times in buildings such as these intimacy and enclosure can be craved and the fire in here can be used independently of the underfloor heating for providing efficient instant heat, on for example a chill summer’s evening.

Whilst the lower ground floor elevations have elements of conventional load bearing cavity construction masonry acting with the steel frame to support the first floor concrete planks in the most space depth efficient way possible, the solid walls at first floor are lightened both visually and physically by employing an insulated render system in lieu of facing brickwork and therefore results in a reduction in load and embodied energy and thereby indirectly, a reduction in cost.

Permanent link to this article: