Monthly Archives: March 2016

Solar panels can generate significant amounts of electricity for example on March 25th our 4kW panels generated 22.4 kWh over the course of the day as shown.
ImmerSUN 25-03-2016
This generation typically substantially exceeds the load being drawn by the house leading to export of electricity to the grid – 12.3 kWh in this example or more than half the generated energy.

Moving loads such as the washing machine or dishwasher from night to day can help use this electricity, but done to excess risks increasing day time electricity import if changing cloud cover or other factors reduces generated power. The varying power demand from such devices is also unlikely to coincide the the surplus power available leaving some unused surplus. I was thus pleased to come across the ImmerSUN system.
The ImmerSUN is a device which diverts surplus power to a range of possible consumers such as an immersion heater. It has a current sensor that measures any surplus power being exported and then diverts a similar amount of power into the immersion heater. Normally of course an immersion heater is either on or off, but the ImmerSUN provides proportionate control between 0 and 100%. It can control several devices diverting power to a lower priority device once, for example, a higher priority immersion heater has raised the water temperature to the set point and power for that purpose is no longer required. In the top illustration the blue bars show 4.7kWh being diverted into water heating (and thus reducing my gas bill) that otherwise would have been lost to export.

For further details see ImmerSUN website .

At the time of writing if you order online quoting Referral Code 206505 you will receive £25 in department store discount vouchers or a free system upgrade to remote monitoring.

New wheels

AmperaAfter seven years of Wizzing the time had come for a change. Back in 2007 there was little else available, but electric vehicles have come on a long way in that time. The most significant driver for a change was something larger that we could get the whole family in – the G-Wiz notionally has four seats but the rear ones are too small for adults or car seats effectively making the G-Wiz a 2+2. I considered various alternatives and eventually settled on a Vauxhall Ampera encouraged by a substantial discount.

The Ampera is a four seater hatchback with an electric range of up to 50 miles. It’s actually a plug-in hybrid, so it initially runs as a fully electric vehicle, but then when the battery is exhausted it runs as a petrol-electric hybrid. Most days (and indeed weeks) I use no petrol, but occasionally I can do long trips of a few hundred miles without stopping to charge. For most of the period of my ownership my lifetime average economy has been 250+ mpg, but that’s dropped to 190+ mpg following a few round trips to Cheshire.

We have moved

Well, after nearly 20 years in the previous house the time came to move. What had started as “One man’s journey” became a couple’s journey and then a family’s journey and eventually the point was reached that enough was enough, or rather non-enough was not-enough when it came to space. A journey that started with my wife proposing a new conservatory (opposed by yours truly) ended up with a significantly larger house about a mile closer to the station. So far for the good news.

EPC scaleThe bad news is that our new-to-us 1970s detached house was rated E52 (on the UK’s scale of A100 to G1 for environmental performance) on the seller’s Environmental Performance Certificate. Fortunately it did have a full set of 2-year-old double glazing but not much else – including it turned out an arthritic boiler that couldn’t heat all the radiators but did manage to heat both expansion tanks in the loft.

So, over the last few months, we’ve been sorting out a few things to improve our environmental credentials and, at the same time, reduce the energy costs estimated at £2,114 per annum (£176 per month) on the EPC.

One of the first things we added was 4kW of solar panels on our south-south-east facing roof. That wouldn’t necessarily have been my first priority as autumn headed for winter, but with a reduction in the feed-in tariffs imminent it seemed sensible to act sooner rather than later. To get the highest feed-in tariff rate it turned out that I also needed a ‘D’ so I switched to low energy bulbs (worth 2 points), fitted the panels (worth 6 points), all of which should have got me 8 points so a D60 and then ordered a new survey..

The new survey came in as a C73 rather more than the D that I’d expected. Key highlights in the different surveys were:
o Walls – from 2 stars to 4 stars as the new survey found evidence of existing cavity wall fill,
o Windows – from 3 to 4 stars after I showed evidence of the installation date,
o Main heating controls – declined from 4 to 3 stars as only 2 TRVs found,
o Lighting – from 1 to 5 stars with all my new low energy bulbs.

Subsequently we sorted out the boiler and controls, so picking up the points values of the latest EPC:
o Hot water cylinder thermostat (as we went from gravity hot water to pumped) – 3 points
o Heating controls (TRVs) – 1 point
o Replace boiler with new condensing boiler – 7 points
o Solar water heating – 1 point

That latest list amounts to 12 points which should have got us from E52 to B85.