Peltier devices need a decent temperature difference to create usable electricity. Making the cold side cold enough might cost you more energy than it's worth.

A better concept may be to directly use the excess heat for area heating.

There might be some merit in this if you could manufacture solar panels which got hot enough to double as solar-thermal arrays, attached to the fluid transfer system, etc. I suspect the panels would need to be black, in order to absorb enough IR. I don't know what temps the voltaic cells can handle.

1. combined electricity and hot water output :http://news.umr.edu/research/2004/solarmonolith.html

2. combined electricity and hot air output :http://www.solarventi.com/generelt/SunModel_UK/index.htm

3. direct heat to electricity conversionhttp://www.varmaraf.is/engl/prod.htm

mount the solar panes on the radiator of a heat pump. you will be able to make more solar power, because solar panels work better colder due to internal resistance, and heat your house cheaply