5.3 Environmental Issues
It is not difficult to make the theological argument that we all have a responsibility to care for the planet. Since the industrial revolution, we in Western societies have consistently lived way beyond our means. If Genesis 1-3 teaches us anything, it is that creation was made good and its spoiledness is down to mankind, not to the natural order of things. Of course some on the religious Right may disagree, but then if that is you, you’re unlikely to be reading this in the first place.
If we combine an understanding that we have a Christian duty to look after the world as best we can, with the plain fact that buildings are a major source of energy use and therefore greenhouse gas production, we should think hard about how we design and use our buildings. And more positively, church buildings present us with ample opportunity to put an environmental theology into practice.
- Building form: The first and most basic opportunities for saving energy are in the orientation and form of the building. The more spread-out your building is the more wasteful of energy it will be, because it will have a higher ratio of surface area (and thus heat-loss) to volume (activity).
- Orientation: Something as simple as how your building is oriented has a significant impact on how much energy it uses. With windows in the right place it can gain benefit from the sun during the winter months, or if badly placed those windows can cause it to overheat in the summer.
- Building Construction: The next place to look is the amount of heat loss through the building fabric. Building Regulations set a (gradually improving) minimum standard of insulation; if we want to be green, we should be aiming to super-insulate our roofs, walls and windows.
- Heat recovery: Any mechanical ventilation system should have a heat recovery mechanism, so that waste heat is not pumped outside but fed back into the building.
- Photovoltaic cells (PVs): These generate electricity for use locally and export back to the grid. This is a technology that still requires a subsidy from Government to make any financial sense, though this level of subsidy has come down a lot. With the subsidy this is effectively a simple investment, with a simple payback somewhere in the 9-13 year timescale. PVs can work very well with a heat pump to maintain the building at a background temperature.
- Heat Pumps: These are electrically powered heat exchangers – it is the same technology as used in your fridge, but used to ‘move’ heat from outside to inside. Heat pumps consume electricity, but for every kW used they produce 3-4kW of heat. This brings the current running costs of a heat pump system to approximate parity with gas (because electricity is much more expensive per kW than gas). The advantage is that gas will run out, but we have more choice as to how we generate our electricity, including of course various means that produce no carbon. Heat pumps source the heat either from the air or the ground; ground source systems either use boreholes to say 100m depth, or coils laid horizontally a little way below the surface. There may be grants available to assist with installing heat pumps. Note that the heat from heat pumps is relatively low temperature; it is easier to make use of this with an underfloor heating system, than with radiators.
- Bio-mass: These are alternative boilers that burn wood, either in log form, or as pellets. This makes financial sense when compared with the cost of oil – ie in rural settings – but will be more costly than gas. You also need to be confident of your fuel supply.
- Rainwater harvesting: This catches rainwater for use as ‘grey water’ – particularly flushing of WCs and of course watering of planting. Whether this is a sensible thing to consider depends on the extent of usage through the week.
- Wind turbines: If you’re on a windswept hill, then this might be a good idea; if you’re anywhere remotely urban then this is not a sensible option to incorporate on your building.
For the reasons mentioned above, many churches aspire to create green buildings. Many projects start with sound green ambitions, but these ‘add-ons’ quickly get cut out again once tenders have come in higher and cost savings need to be made. The issue therefore is how to make these technologies ‘stick’.
There are no easy answers to that, but the first three of the ‘technologies’ above (Building Form, Orientation and Construction) are much more integral to a project design and thus more difficult to omit later; they should also be the place we should always start anyway. Our observation is that the more something is seen as a nice-to-have add-on, the more likely it is to get cut out. The issue therefore is how well-rooted these green aspects of the design are in the overall picture of who you are and what your project is about. The issues thus comes back to one of vision, and therefore of theology.
The Diocese of London has a lot of well-written guidance, including a long section on Sustainable Building. It is an excellent overview of what is a complex area, and includes information on materials, embodied and life-cycle energy, and some information on specific technologies. Shrinking the Footprint is another site maintained by the Church of England with a wide range of resources, and is of particular relevance to historic church buildings.