A Green Retrofit on a Modular Home
The Electrical System, Part 1

Before designing my electrical system, I need to determine what my general electric usage is right now. That's available from the printouts/bills sent to me each month by my local Rural Electrical Cooperative. In the end, I want to make sure I have enough generating and storage capacity to meet and exceed my needs without breaking my wallet at the same time. As I'm financing the entire project out of my pocket, I'll break the project down into easily managed steps and move ahead step-by-step.

After perusing a year's worth of electric bills, the first thing I need to do is simply reduce my consumption and get a more realistic estimate of my overall needs. So step number one is to cut out all the fixed incandescent lighting in the house and replace it with 12-volt LED systems, most likely in the form of track lights that can give me better lighting coverage from bright light sources that essentially never burn out (there's a reduction in the bill right there). And one of the joys of a 12-volt system is it lies outside the purview of the National Electric Code, hence, no permits and no inspections needed.

Keeping in mind the overall objectives of my project, one of the very first things I have to do is locate where my new "breaker box" is going to be. As I'm looking at using a mix of solar and wind electric generators feeding the house through a battery storage system, I need to locate a place outside my living space to build the battery room. I have a great spot already picked out under the deck outside my great room, up against the six-foot-tall concrete wall. The battery room can be built of block with a direct feed through the wall into the new breaker box located inside the "walk-out crawl space" with easy access.

So when I say "fixed incandescent lighting," I mean all the ceiling-mounted light fixtures in the house. To replace these I'm first going to run 12-volt wiring through the attic space to feed the new ceiling lights in every room of the house. In my beginning research for this project I went up into the ceiling to look at what I had to work with in the attic space. And here's my first major modification to the first rough draft of my plans:

When we originally ordered this home from Atlantic Homes, we specified at least an R-30 insulation in the roof. In cutting a hole and sticking my head up in there, I discovered some "blown-in" crap about 2" thick that had been passed off as "R-30 or better insulation." And even then, that stuff only covers about 3/4 of the total ceiling area in the house.

So, that makes it easier for me to run 12-volt wiring all over the attic area, but when I'm done with that I need to open up the ceilings all over the house and insulate with real insulation of a proper thickness. Then I'll need to redo about 2,000 square feet of sheetrock ceilings in the house. That's not going to be cheap and it's going to take some time, but from a future heating system project perspective, it will be money well spent. While I'm thinking about that future heating system project, I think I'd better run the wiring I'm going to need for the various zone thermostats in the house, before I start closing up the ceilings again.

So I can go ahead and run all my 12-volt lighting and thermostat wiring in the ceilings at once, then proceed with the insulation and sheetrock project one or two rooms at a time. Somewhere in that time span I'll be building the battery room and getting that ready for the day when I can plug in and turn on those beautiful new 12-volt LED track lights. While I'm at it, I can go under the house and install a 12-volt feed to the water pump/filter system that gives us running water in the house, and swap out that AC pump for a more efficient DC pump. Doing all of this will get about 1/3 of my home operation off the public grid, and give me running water and lights in all those times when the Rural Electric Cooperative simply can't keep the power on (which happens more often than you might think).

Because of the overall weather conditions in my location, I'm thinking to go with a mix of wind and photo-voltaic generated power feeding into the battery storage room. This is where my calculations of necessary capacity come into play: power generation and battery storage needs to be large enough to feed both the straight DC systems and the DC/AC inverter that's large enough to feed all the electrical outlets in the house. And because of those same overall weather conditions, I think I'll check out turning that bicycle exerciser in my workout area into something that can power a flywheel-type generating system for those short solar days of the year when we're sometimes up to our ears in snow... a little healthy human power can go a long way sometimes.

Update: After doing the math and seeing that the voltage loss in long distance DC power lines was just too much, I decided to not run the 12-volt lighting systems. But I did tear out the ceilings, run thermostat wiring for the different zones, replace the insulation with real R-30 and then replace the sheetrock in the ceilings. As for electric power, I went with a PV solar array feeding into a battery room and then thru an AC/DC inverter to the house. But that's the next installment of this story...