2009
07.24
07.24
We’ve had an evacuated tube solar panel system for just under a year now (they were commissioned on 26 August 2008) and I’ve been gathering data since the commsioning date. I’m a born skeptic, and continually have to prove to myself they do actually have an ROI. I was going to wait until the full year to publish the progress but I couldn’t wait because data excites me rather more than it should. SO for now, I’m just presenting a simple Kw/H output analysis up to today (01 October 2009).
26 August 2008 - 01 October 2009
About the system
- 60 evacuated Tubes situated on a South/South West roof
- 300L Solar Tank with dual immersion (solar and electric)
- Digital controller with full statistical telemetry
- Solar pump to distribute the hot water automatically
- Cost was €5200 with €1668 returned in grants (€3552 net)
Some interesting notes about having solar..
- We have had the gas boiler switched on (in boost mode) for under 2 hrs in the last 2.5 months. As we pay our gas bill on a budget plan (that is, spread over the year to balance out the monthly payments), I would expect to see a significant drop in bills towards the end of the year.
- We had a new condensing gas boiler installed on 30 June 2009 which involved flushing out the entire heating system and redoing to heat venting (adding an expansion vessel) which seems to have improved the overall heat retention in the 300L hot water tank (which is factory insulated)
- The water has been consistently hot at 40 degrees every day over this period, both day and night.
- Our washing machine, which draws from available hot water, finishes its cycles more quickly as water does not need to be heated by the internal elements. However, because the w/machine does draw hot water, we now do our washing in the mornings after showers!
Okay, but what about the beef? Will these things save me money? What’s the upswing?
- I’m currently in the process of looking at the Kw/H consumption of both gas and electricity over the last 2 years (i.e., 1 year prior to solar) and plan to overlay both data sets on this graph. I felt that using the money amounts wouldn’t be relevant as they’re variable. Clearly, if I’m using less KW/h then it’s working for me, and I can calculate an ROI easily enough.
- There is no question that the solar panels, and measures such as the condensing boiler, wall and attic insulation will have elevated by BER level and I plan to have a BER certification done towards the end of the year. The preliminary estimate of a BER (conducted in August 2008) rated us at D1.
So there you go. If you think this information is useful,I’m happy to continue blogging about it, but do look back again in a while when I have the other energy consumption data available and overlayed with my conclusions and estimates on ROI figured out!
Interesting stuff. I’ll look into similar measures when I get myself into a house I plan to stay in for long enough to benefit.