I recently had an amiable conversation with the Sales Manager from a well established Solar PV Distributor. During our conversation he asked if I had photovoltiacs mounted on the roof of my home. Now anyone that’s ever sat in one of my classes knows that I firmly believe the cheapest alternative energy is that which you don’t need because your house is energy efficient. In other words, to limit the cost of your alternative energy-producing components, improve the airtightness of your building. Based on the common sense of efficiency first, I replied, “My 100+ year old farmhouse isn’t energy efficient enough yet to justify investing in solar panels”. His unflinching response was “It doesn’t matter!” and that I should be taking advantage of free energy. He said his house wasn’t energy efficient either but he enjoyed lower energy bills because of his solar panels.
The notion that energy is free is ridiculous. The law of conservation of energy states that energy can neither be created nor destroyed. It can, however, be transformed via a little thing we call work. And last time I checked, work ain’t free. The energy that a solar panel produces does so at a very calculable cost. Those costs include the material cost, installation cost, maintenance costs, the depreciated value of the system over time, and ultimately the replacement cost.
Your heating and cooling costs make up 40-60 percent of the total energy used in your structure, therefore, saving on heating and cooling gives you the most bang for your buck. This is better done by by air-sealing your envelope or upgrading insulation then spending $4500 per kilowatt for PV. In addition, you’ll find it amongst the talking points of both Efficiency First and the DOE’s newest program, Challenge Home.
Believe it or not, I’m a huge fan of Solar. I wouldn’t hesitate to install or specify a photovoltaic system in concert with an intelligently designed and built home. If you were to ask me how I’d define Solar-ready, I’d unflinchingly reply that the HERs rating should be below 50 – without any reductions from alternative energy sources.
The solar industry has brought increasingly more affordable panels and along with improved PV efficiency, the sales of roof mounted solar panels has grown exponentially. All this, combined with increased building energy efficiency is an amazing step forward into a future we should welcome. However, I will continue to always recommend improving efficiency as a more intelligent way to invest in your home’s future.