I'd like to make an investment in renewable energy at my 40-year-old split level in McLean, Va. I have added cellulose insulation in the attic, purchased EnergyStar appliances, got rid of the garbage disposal (compost kitchen scraps), use my clothesline almost exclusively, have 100% CF lightbulbs, a Solatube and solar-powered attic fan. I have a gas furnace and hot water heater. I'm thinking of a geothermal heat pump and/or a solar hot water systerm. I don't use a lot of hot water (one person household, cold water laundry, plus I usually shower at the gym), but when I sell my house, it would be good to know that the next family would have the solar system. I understand that the geothermal system will supply all of my hot water in the summer. Would it make sense to have the solar hot water system as well? And if so, would you go with evacuated tubes or flat plate? My roof faces Southwest. (I had thought solar hot water with a radiant floor heating system would be a good idea after seeing similar systems at the Solar Decathalon, but a contractor here said it would be wasteful due to no use for the hot water in the summer.) Thanks so much. I've already learned a lot on this forum from Gary and Bob and others! The IGSHPA website was especially helpful. Rose