Green office retrofit

The green building retrofit we have undertaken, and are continuing to refine, in our small office building is important because it;

  • acts as a test bed / demonstration facility for energy efficient building elements, energy using equipment, air-conditioning and lighting and renewable energy, 
  • it demonstrates our passion for and commitment to sustainable practice, energy and water sustainability,

Environmental initiatives implemented so far include:

  • reusing a 70 year old building,
  • installing sensor controlled, high efficiency T5 fluorescent and LED lighting,
  • ceiling insulation (two layers of polyester batts, with total R value of 4.5),
  • insulating the double brick wall cavities, using pumped-in ‘eco-Foam’,
  • insulating under the timber floor, using polyester batts,
  • installing a 5 kW solar photovoltaic system,
  • provision of under-cover bike parking, shower and locker facilities.
  • re-‘gassing’ all air-conditioners with natural refrigerants which have a much lower global warming potential than man made refrigerants, and which reduce electricity consumption.
  • installed high efficiency DC ceiling fans, to distribute warm air, reduce heating requirements and reduce the need for refrigerative cooling (while improving  comfort),
  • painting walls white, to make the best use of daylight, improving the quality of the working environment and reducing electricity use (no electric lighting is required in any part of the building during the day).
  • replacing all windows with double-glazing incorporating low-E coating, argon gas, and thermally broken framing.
  • replacing single flush toilets with dual flush, and rectifying leaking valves.

Results

The thermally efficient building retrofit has resulted in much better comfort than our previous building, which was similar to this building before the retrofit. The temperature typically stays between 17 and 24°C, with the ambient temperature ranging from 1 to 45°C.  But this doesn’t tell the whole story…….  because of high thermal mass of the double brick, much of which is inside the insulation barrier, the surface temperatures are moderated, and so the radiant temperatures in the office are moderated.  This improves comfort, and so the air-conditioning is only called for when the inside air temperature is below 18°C or above 27°, which seldom happens because of the high insulation levels. Sothe air-conditioning is used for less than half of office hours in the depth of Winter or the hottest weeks in Summer, and not at all during mild weather.

 The solar PV system generates more electricity in a year than is consumed in the building.Despite having more than twice the number of staff than the previous occupant and staff cycling to work (and showering), we have cut water consumption by 90%.

Next Steps

We also intend to implement the following sustainability initiatives:

  • installing a rainwater harvesting and stormwater peak detention system,
  • establishing a teleconferencing facility to reduce travel requirements,
  • improving water heating (currently gas storage — considering solar pre-heating, instantaneous gas or electric heat pump, and drain heat recovery).