...seriously, though, the gizmo ("merging device") is called an inverter. Logically (if not physically), it hooks in below the meter because the object of the grid-tie game is to cause your meter to "spin backwards", as they say. If you're designing a new house with solar power in mind, it's true that the wiring run between PV arrays and inverter/meter is one consideration. Much more important, however, is the orientation of the roof surface(s) if you plan on putting panels on the roof. The ideal case is a roof plane which is never shaded during sunlight hours and faces due south with a pitch (angle) more or less equal to your lattitude. These issues are also covered in various solar-oriented magazines, blogs and books.

I think we all pay attention to it but do so indirectly, not in any formal or scientific study sense. But we consider it indirectly in the gardening aspects of picking the best sunny yard spot for the garden, E-W bed orientation when possible, plant placement to avoid shading of other plants or plant placement to provide some shade for other plants, ambient air temp dictated by the sun and its effect on plants, deciding when to water or when to apply foliar sprays, etc. Home gardeners don't have the cultural control advantages that large commercial growers do. We don't have the acreage, the equipment, the working staff, the funds, or even the need to produce for corporate profit they have. So we make-do with what we have and work to control what we can. The rest has to take care of itself. ;-) Dave

Hello Cecelia, during the architecture process you may include many design elements that can help reduce the overall electrical load of the house before the calculation for the PV panels are taken into consideration. As a rule of thumb in order to maximize the photovoltaic system capacity you may wish to implement more insulation in exterior walls (specially east/west) and the roof to lower A/C loads, that amount to most of the electrical load of the house. Also you may want to implement overhangs or exterior shading on the windows and/or use insulated windows to lower the sun heat to the inside of the house. Using high SRI roofing and light colors on the outside will also help as well as using low albedo surfaces for ground cover and implementing planting areas around the house will help with the interior heat load. In terms of cost for solar in Puerto Rico it has come down in recent years and there are tax incentives for PV panels as well as for the batteries that have been in place for the last couple of years that may help as well. It hasn't been as easily accesible in PR as in the past 5-7 years so that is why I believe it isn't used as much as in the mainland. It is becoming more and more common, as is the batteries use after hurricane Maria. In your PV design you may want to include batteries as well as a generator that may complement each other in case of power failure so fuel or gas is not as expensive as it would be if you were running the house completely by the generator and the size of the generator can be smaller as well. Hope this information helps, and if there are any questions that arise from my comment I am happy to help.

@mtvhike: the problem is, you don't get your 1200 watts continuously. In cold weather / short days of the year, your 1200 watts rated panels might only produce that much (total) for a couple of hours worth. (You can look up calcs depending on how far north you are). So let's be generous and say 3kwh for an entire 24 hour period. About the same as two 60-watt lightbulbs running all day. Don't trust me, do your own plausibility checks. So I just don't think it's going to make a meaningful dent. And at a relatively high price. Also, I think you'll find that solar, installed, with wiring, etc., will cost several times the cost of the panels. But again, check with local cost and installers. To throw out some ideas: for bang-for-your-buck, it may be possible to add extra heat storage to your hydronic system (e.g. an extra tank of water, although there are more technological solutions). Then you'd get the extra heat delivery from that stored heat by getting enough reserve power (battery or generator) to keep the circulation pumps going. As above, a generator would give more ability to ride through long outages - and also may be able to provide enough power for partial load of the boiler. (Some might suggest wood stove for backup - I'm not getting in that discussion...) Yes, can be hard to find air-to-water systems. Hope the thoughts above help.