Need Solar-v-Weatherization savings comparison graph

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Permalink Reply by David Meiland on April 10, 2011 at 4:10pm

I don't know how simple this question is. There is data on weatherization outcomes available, but there are a lot of variables, such as region of the country, who's in charge of the money and the work, type of housing stock, etc. Solar is going to vary too, because of differences in how much the sun shines and how much utility power costs.

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Permalink Reply by Robert H on April 11, 2011 at 4:24pm

Weatherization is where to start. I dont have figures but look at the cost to supply 50% of the energy needs of an existing inefficient house using solar verus the cost to reduce demand by 50%.  It wont be close.

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Permalink Reply by Energy Efficiency Eric on April 28, 2011 at 8:43pm

To show the importance of efficiency first, I used to use an example comparing light bulbs to a PV system, as follows. But solar lease options on the market have changed the game, making little to no capital outlay and instant energy offset for some systems in states with utility rebates. I know this doesn't exactly answer your question. But maybe it's worth a thought. Efficiency first is the right thing to do, but solar has it's place too.


Ten (10) 100-watt incandescent light bulbs x 10 hours/day = 10kWh/day (3650 kWh/year)
Ten (10 20-watt compact fluorescent bulbs x 10 hours/day = 2 kWh/day (730 kWh/year)
                      Difference: 2920 kWh/year

One 2,000-watt PV system x 1.45 (*Boulder Colorado - www.pvwatts.org)
                               2,900 kWh/year

 

        $50 for a light bulb vs. $5000 for the PV array*
                        What would you do?

 

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Permalink Reply by Kris Grube on June 20, 2011 at 10:51pm

Nice, Eric.  This is the sort of info I'm looking for.  I appreciate your input.  Thanks, Kris

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Permalink Reply by Jack Baikoff on June 22, 2011 at 4:34pm

Having worked in both PV installation field and being an energy auditor I would say that this should not be raised as a question of one VS the other, they should go hand-in-hand, weatherization preceeding solar installation.

Also I would suggest considering solar thermal before solar PV.

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Permalink Reply by Tyson Pischel on June 29, 2011 at 7:19am

This Study posted on the Northwest Energy Star site may be helpful.  It has case studies for four or five homes approaching net zero.  they summarize the cost of reducing energy needs along with the costs of adding renewables.  It also does a fairly good job of summarizing issues we run into when taking energy efficiency to the next level.

Hope this helps.

 

http://www.northwestenergystar.com/sites/default/files/resources/NZ...

 

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