This time the snow lasted only a few days and we're back to our more usual rain. However the last few days have also given us some brilliant sunshine with temperatures up to 20 degrees. Since this global warming thing really got going it often seems as if Ireland has only two seasons: A very wet winter, and a monsoon summer season.  (I'm blaming the cold winter of the last two years on reduced sun spot activity or just random variation).

The lambs didn't much like the late snows either. Food and shelter were in short supply.

It was therefore past time for me to get some much needed insulation work done.

And while I was at it, a new window in the attic for my daughter's bedroom.  

A mixture of glue and silver polystyrene pellets is pumped through small holes drilled into the outer wall to improve the insulation of the cavity walls.  I hate the way those guys use ladders without any safety precautions.  

The literature claims that the heat loss or (PDF alert) U value of the walls will be improved from c. 1.55 w/m per degree to c. 0.4. (Watts per Meter Squared per Degree Kelvin or W/m2K). What this will mean in terms of actual heating bills and ambient temperatures I won't know until next winter, but early indications are that the ambient room temperature will be about 2 degrees higher for a given level of heating when the effects of the wall and attic insulation are combined.

A much larger tube was used to blow rock wool insulation into the attic to a depth of at least 300mm - here seen entering the house via a newly rebuilt porch. (The old porch had been bulging as if harbouring a slow growing volcano underneath.  It turns out the original builders had dumped some surplus lime into the foundation which expanded on contact with water...).

The improved attic insulation is probably the most cost effective in terms of its insulation efficiency, but the Sustainable Energy Authority Ireland grants for house insulation are only available if you get two jobs done so I included the cavity wall insulation in the plan as well.

The next stage in the renovation/insulation project is to decide whether to go ahead and install two thermal solar panels in the roof. My house is ideally situated in that I have a 30% sloped south facing roof and the panels wouldn't look dissimilar to the two Velux windows already installed in the roof on one side of the house (see photograph of house at the top of this story).  

Picture of solar thermal panels taken from promotional website

The best quotation I have received so far is for c. €3,000 to install two panels (totalling 5.4 square metres) and a new immersion tank with all the relevant pipework and controllers - with a claimed saving of 30% of household heating and hot water bills which in my case would achieve an annual saving of c. €600. However I don't believe by savings would be anything like that, and the principle benefit would be from higher ambient room temperatures within the house.

The claimed lifespan of the system is 20-25 years with a maintenance cost of c. €300 every 5 years to replace the glycol fluid.  However one of the companies, which claims to have installed 15,000 systems in Ireland and the UK over the past 5 years could give no hard figures of actual savings in energy bills achieved by householders with previous installations - choosing instead to include some woolly testimonials on their brochures and website.

Perhaps some readers here have experience of similar installations and can give some more hard figures, but I suspect my decision will end up being based more on a desire to reduce my carbon footprint and inflation proof my future heating bills.  The company in question doesn't do photo-voltaic panels claiming they are uneconomic in Ireland. I'll probably end up getting a couple more quotations in order to compare installation options and prices before I make a decision, so any advice you might have would be very welcome.