In the cause of mitigating and adapting to climate change within the diocese, the primary focus is on managing our use of energy and related resources. Energy consumption, directly or indirectly, is the greatest contributor to changes in climate, mainly through the production of ‘Green House Gases’ (GHGs) such as carbon dioxide and methane. In our church buildings, we may not be great consumers of energy, sometimes only on one day per week, but there are still opportunities to achieve significant financial savings as well as contributing to energy conservation.
While ecological conservation may concentrate on our church grounds, developing biodiversity in order to encourage carbon sequestration, our main energy consumption is through heating and lighting. This guide is aimed at determining savings that might be achieved from taking advantage of the fast changing technologies in lighting, an important component of church fabric, including external flood lighting.
Old incandescent filament light bulbs have now joined the dinosaurs and are no longer readily available but the alternatives use far less energy and therefore also cost less to run. The disadvantage is that some find the quality of the light less attractive. The initial advent of the halogen light bulb (still available) achieved some savings but it was replaced by the ‘Compact Fluorescent Lamp’ (CFL) which was much more efficient but suffers from using small amounts of mercury which makes them environmentally undesirable. CFL lamps are still available, largely as tubes, but the lighting revolution arrived with the Light Emitting Diode (LED) lamps which offer large savings in energy and running costs despite higher initial cost. LED lamps now come in many forms which allow them to directly replace former incandescent bulbs. Moreover, most flood lights are almost exclusively LEDs now.
In the light of rapidly increasing energy costs, the investment required to change to LED lamps is ever more attractive. The following table sets out the notional savings that can be made by switching as much as possible to LED lamps. It is based on current (April 2022) electricity rates and costs including VAT as well as manufacturer’s indications of lifespan. While 15,000 hours may seem an optimistic lifespan, it is the notional durability for a LED lamp and is probably reached long before the 13.7 years that it might represent!
Comments and observations are welcome.
Paul Johnston, Glebes Environment Committee, Tuam, Killala and Achonry.([email protected])
Cost Comparison Between LEDs, CFLs, Halogen and Incandescent Light Bulbs
| OLD INCANDESCENT FILAMENT | HALOGEN | CFL COMPACT FLUORESCENT | LED | |
|---|---|---|---|---|
| Light bulb projected lifespan in hours | 1200 | 2000 | 10,000 | 15,000 |
| Energy use – watts per bulb (old 100watts equivalent) | 100 | 77 | 20 | 10 |
| Cost per bulb in euro | 2 | 3.5 | 8 | 12 |
| KWh of electricity used over 15,000 hours, per bulb | 1500 | 1155 | 300 | 150 |
| Cost of electricity (at € 0.225 x 1.135 VAT= €0.26 per KWh) | 390 | 300 | 78 | 39 |
| Bulbs needed for 15,000 hours of use | 12.5 | 7.5 | 1.5 | 1 |
| Bulb expense for 15,000 hours (euro) |
25 | 26 | 12 | 12 |
| Total cost for 15,000 hours for one bulb, in euro | 415 | 326 | 90 | 51 |
| ENERGY SAVING OVER 15,000 HOURS, ASSUMING 20 LIGHT BULBS IN A CHURCH (2KW) | ||||
| Total running cost for 20 bulbs in euro | 8300 | 6520 | 1800 | 1020 |
| Saving by switching from old incandescent bulbs € | 7280 | 5500 | 780 | 0 |
NB. 15,000 hours for a bulb is equivalent to 13.7 years at 3 hours per day.
Tungsten filament (old fashioned bulbs) are the greater consumers of power for lighting. The following table is to assist in completing an inventory of these bulbs in parish buildings and to help in determining any cost savings to be made.
TUNGSTEN FILAMENT BULBS
| A WATTAGE |
B NUMBER IN USE |
C ESTIMATE OF HOURSOF USE PER WEEK |
Kilowatt hours/year KWh = A x B x C x 0.052 |
|---|---|---|---|
| 40 watts | |||
| 60 | |||
| 75 | |||
| 100 | |||
| 150 | |||
| 200 | |||
| Flood lights 500 watt? | |||
| TOTAL KWh/year |
Multiply the total by the current rate of ~ €0.26 per KWh incl. VAT = cost per year
How does this compare with your current ESB bills? What else is consuming electrical energy in the building?
Notwithstanding ‘standing charges’, compare the cost of substituting low wattage LED bulbs in spite of the cost of replacement.