ok, so natural gas would win out in the above synopsis. in a normal gas furnaces, would running a fan all of the time help in moving air throughout the home and keeping a more even heat? I am experimenting running my fan while the heat is off the last couple of weeks and I am finding that the heat tends to kick on more as I assume air movement is better to the thermostat. Regarding the solar, on the longer / brighter summer days i produce just over 50 kWh, over the past couple of weeks (november) with less sun, it varies from 5 kWh on very overcast / cloudy days up to 32 kWh. winter sun is lower and shorter hours vs summer. Until i have a full year under my belt, it will be hard to fully understand the true savings and production. Thanks for the cost comparison. It may be better to stick with gas as the solar produces a lot less in the winter sun. the strength of our area is that is covers a lot of energy when our electric use is the highest with AC on.

IÂm in MA. Our system = 5.588kW. Even with the cloudy days and we still have one big tree blocking our panels until 10am), I think we generated over 640kW in May. The time is now for us to get solar panels because: 1. We qualified for 2 big MA credits, which took $10,500 straight off the total cost, which was a BIG helper toward reducing our break-even to just over 6years. 2. The Federal 30% rebate has no cap for solar/etc, which will take almost another $10K off our bill. 3. (KITCHENDETECTIVE) MA does net-metering, which means that on the days that we produce more than we use, the electric meter turns back (to reduce our bill from when we donÂt generate enough and have to buy off NStar electric company). 4. We are locked in until 2016 for SRECs, which are money generated from selling our green credits on the energy stock market (for those who need green credits to offset their horrible carbon footprint). It may/may not continue after year 2016, at the same/lower/higher rate, not sure. 5. And weÂre not moving so after break-even, we could possibly make money (instead of paying over $300/month on our electric bill). And we want to install central air (my husband use to give me a hard time when I want to turn on the window A/C). 6. Lastly, we have a great home equity line with ~2.24% interest rate. 7. And our house faces north, so no one can see our panel (on the back roof). The installers noted that itÂs like our house was built w/ solar panels in mind, in terms of the orientation. Note: we had to take down 10 big trees to allow more light (which we would have done because our backyard was all moss due to lack of sunlight). We actually want to take down 6 more next winter. BUT I have a nursery growing 9 pine saplings ready to replace some of those trees. We chose a turn-key solution from a local company who did it all for us. We even had to upgrade our electric panel from 100amp to 200amp, and we can include that in the Fed rebate. They quoted us 3 different panel brands; we chose Evergreen, the 210 panels. ThatÂs like getting a nice base level Audi (the price for the value = efficiency level), vs. the Lamborghini or the Kia. Florantha: 1. "brag as you have bragged": I hope you do mean in a positive/supportive way because I donÂt mean to upset anyone. IÂm just excited. 2. Where are you located? We looked into geothermal and for our land (only 1.1acres), the cost of digging and the system would be over $35K and the break-even would take over 13years, so it doesnÂt work for us, and we would still need a back-up system for when it gets really cold (often).

Sorry this post is long. If you get too bored, just skip to the next-to-last paragraph. So far nobody has yet found the perfect battery. All of them are balances of cycle life, cost, safety, temperature range tolerance, specific energy (Wh/kg), energy density (Wh/l), specific power (W/kg), charge efficiency, and probably some factors I've forgotten about.. No one battery type has them all nailed down, and probably none ever will. The battery that might make its way into a home power system today would most likely be lead or lithium ion. A few others have been used but are now mostly on the sidelines. These include nickel cadmium, nickel iron, and nickel metal hydride (which is really just improved nickel iron). Lead is the traditional battery for home power systems, but it has significant downsides. Specific energy and energy density are low. Flooded types need watering and periodic testing. Cycle life is good for heavy, expensive tubular plate types, not so great for conventional flat plate batteries. Lead used to be the uncontested leader in cost per watt-hour delivered, but in recent years lead metal prices have increased and it's no longer as competitive as it once was. Nickel iron is legendary for extremely long cycle life. I've read that some of the original NiFe cells built by Thomas Edison are still in service! Their specific energy and energy density are better than lead, but not dramatically so. Efficiency is a weak point because they gas too freely (too much energy going into electrolysis), and this also requires careful ventilation. The few NiFe manufacturers charge nosebleed prices, which limits their use. Nickel cadmium has long cycle life and decent specific energy and energy density. Their big problem is that cadmium is nasty, toxic stuff. Because of this they face severe restrictions in the EU. Nickel metal hydride batteries have sort of been lost in the lithium shuffle in recent years. They have long cycle life and quite good specific energy and energy density. The problem has been that they're encumbered by restrictive terms issued by the patent holder, but I think the relevant patents may expire later this year. The other big negative with NiMH, as with other nickel chemistries, is that nickel is expensive. If given a chance, I think NiMH could still become competitive, but don't hold your breath. Recently lithium ion batteries have grabbed the spotlight almost to the exclusion of any other type. Note though that they aren't all alike. There are several different chemistries with different balances of those concerns I mentioned above. Beyond that, each chemistry is optimized differently by different manufacturers with different design goals. In general I'll agree that lithium ion can be a bit touchy about temperature, certainly more so than lead. Some lithium ion cells shouldn't be charged below freezing (0C / 32F). Others can accept a charge down to -10C, and a few are OK as low as -30C. Again, it depends on what the battery manufacturer is optimizing for. In most home power systems this isn't a problem, especially if the battery is located in conditioned space. The battery's own internal resistance will keep it warm with any normal current use. Insulation and controlled ventilation will keep the temperature in the acceptable range. OTOH very warm temperatures can reduce lithium batteries' cycle life. The more fully charged they are, the more they suffer. So you limit the charging rate at low temperatures, charging slower and slower as the temperature falls, and eventually not at all. On the upper temperature end, you don't charge the battery completely if you expect, or already have, very hot temperatures. Because lithium batteries are fussier than other types about over-charging and over-discharging, they almost always are sold with battery management systems (BMSes). Good lithium ion BMSes know what their batteries are capable of. They monitor the cells' state of charge (or at least their voltages, which is not quite the same thing) and usually also temperature. They control the charging and discharging functions to suit, for a compromise between capacity and cycle life. To cut to the chase, based on Tesla's track record (no pun intended) with their cars, I expect that they'll be more than competent when it comes to their Powerwalls' battery management. As for whether a Powerwall or two can store enough energy for your household needs, that depends on many factors, including how you heat and your overall energy efficiency. Most off-grid folks have to make some lifestyle adjustments when they're no longer drawing their energy from an apparently bottomless source (the grid). If they don't, it probably means their pockets are pretty much bottomless. :-\

In the line where you give the name of the person who had you install your system, I think you need to change the spelling of the word that describes him (if you can - sometimes the original poster has only a limited time to edit, e.g. one day). ole joyful, who frequents "The kitchen table" but finds it hatd to access it, lately).