We received planning permission for an extension in early 2010 and the timely news of the LCCC grant for HNLC and, as part of this, the availability of householder loans for carbon reduction initiatives, allowed us the option to review the specification and content of the work to incorporate some energy efficiency improvements. Having sounded out some of the experts at HNLC and consulted the panel of approved suppliers, we embarked upon the following in order to take the opportunity to improve the carbon-friendliness of our home:
– a 21 panel array of solar PV generating 3.6kW peak electricity
– a 30 tube panel of solar thermal water heating
– improved insulation in the extension equivalent to double the standard of current building regulations
– retro-fit of loft insulation to bring the existing house up to the same standard as the extension
– replacement of the windows in the existing house with A-rated windows to match those in the extension
– replacement of our aged oil boiler with air source heat pumps which will also drive the under-floor heating in the extension
We are now in December 2010 and the work will not be complete for a couple of months yet but our experience so far has been very positive. Fortunately, the timing meant that the additional work could be incorporated into the builders’ schedule with minimal impact on cost and timescale. Our solar PV has been active for three weeks now and we have generated nearly 100 units of electricity (2kW peak on a sunny day), even in these gloomy winter times. That amounts to nearly £50/month in Feed in Tariff (FiT) payments from our electricity supplier. We expect this to rise to over £100/month in the summer and this is in addition to the free electricity if we are able to use it at the time it is generated. We haven’t noticed much difference in the taste of solar powered tea but it certainly refreshes the parts other teas can’t – the conscience! Our solar thermal system has been actively heating our water for a total of 10 hours so far and I am amazed to see that, even in the depths of winter, a watery sun can generate temperatures of over 30C in the panels which, as ours catch the afternoon sun, provides a timely top-up and reduces the requirement for the overnight immersion which we are temporarily using until the heat pumps come on stream. In the summer, we expect most of our hot water needs to be met by the solar system.
Speaking of heat pumps, the plan was to install these in January and then retire our elderly oil boiler. However, the said appliance must have got wind of its impending fate. It lost all motivation and, with it, the will to live. In a final act of defiance, it sprang a leak, emptied the contents of the central heating system over the kitchen floor and expired. Whereas last week we were marvelling at the effect of the improved insulation which meant that our little noses were no longer cold in the early winter mornings whilst the heating struggled to overcome the overnight heat losses, we are now back to additional blankets, hot water bottles and fleeces both night and day until the new heat pumps can be rushed into service. With arctic winds forecast to return, I dread to think what it would be like if we did not have the additional insulation and improved windows.
Whilst it is difficult to quantify the benefit of these initiatives and also to understand the impact in the grand scheme of things, the manufacturer estimates that the solar PV and solar thermal systems combined will generate the equivalent of around 5000 units of electricity per year and save 2.5 tonnes of CO2. Switching from an oil boiler to a heat pump with up to three times the energy efficiency will make further savings as will the increased insulation which means we consume less energy as well.
Further good news comes in the form of the Renewable Heat Incentive which is another government scheme that, from April 2011, will subsidise renewable energy heating (such as heat pumps) in the same way that the FiT does for electricity generation using solar PV and wind turbines. Come next year we expect this to mean that we will be financially self-sufficient in energy in that government incentive payments from the energy that we generate will more than outweigh our total home energy costs – at least for the 25 years or so that the incentives last.
In case you are wondering why the government is being so generous, it is partly because they are way behind target in meeting their legally-binding commitments to increasing the proportion of renewable energy that we use in this country and it is cheaper overall for them to subsidise individuals than to pay the EU fines that might result from failing to meet targets. Whilst the generosity of these subsidies won’t last indefinitely, they will have to be maintained in some form if these targets are to be met. It is therefore not too late to take advantage of these subsidies and do your bit to help both your own pocket and the environment. We are certainly grateful to HNLC for making us aware of the opportunity, providing sound advice and helping us to fund the up-front cost with a householder loan.