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is solar enough

cole Member Posts: 1
I am building a garage in central Illinois.  I plan on using in floor radiant heat.  I would like to know if I could heat it using only solar power. The garage is 30x40 with 10 1/2 foot ceilings.  I did use 6 inch walls and very well insulated doors.


  • ABSolar
    ABSolar Member Posts: 41
    garage heating

    Hopefully, you put at least 2" (4" even better still) foamboard under the slab and outsside the upper foundation wall. And hope you faced the roof due South with at least a 40 degree slope.  And hopefully, you have allocated some room for mechanicals and water tank storage.  Yes, it can be done 100% on solar energy, but most designers advocate against because of the law of diminishing returns in the financial infrastructure investment.  But it can be done.  Throw enough collector panels on the roof and enough storage volume in the mechanical room, and one could achieve 100% solar energyspace heating.  But most don't because of cost.  For economical space heating, throw more money towards superinsulating the structure first, before investing in the mechanicals to make/ gather, and distribute the heat.  Remember, you're talking thousands of dollars just to do 50% and it's not a linear scale for investment. 

    AB Solar
  • Kevin_in_Denver_2
    Kevin_in_Denver_2 Member Posts: 588
    Passive Solar

    Direct gain passive solar windows are the most cost effective way to get solar heat into the space.

    Air leaks around the overhead doors will suck it all out though.  Sealing those doors is tough.

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  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    I had a student once...

    who invited me over to see his house. He had a 2 car oversized garage. He'd poured tubing into a thickened slab with 2" XPS insulation below that. He also had a 15' X 20' space on the North side of his garage (parking pad in front of garage) that he'd put tubing in at 12" O.C..

    He raised red earth worms in the garage, and said that they could NEVER see temperatures below 45 degrees F, or they would die.

    He had covered the ground on the South side of the garage with 10' solar panels in a "lean to" fashion, with the panels at 55 degrees (Denver) and had a simple control logic that turned his pump on if the collectors were over 100 degrees F. There was a simple thermostat on the wall, and if it was satisfied, then a 3 way diverting valve would send the solar heated fluid out to the parking slab.

    He said in the 5 years that he'd been running it, that he'd never lost any worms, and had never shoveled snow from the North side of his garage.

    His walls were 2" X 6" and were insulated with foam.

    Your milage may vary....


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