Thursday, May 26, 2011


Well, after 11 months, our system remodel has drawn to a fitful conclusion. The contractor spent the last month going through the "punch list" of items like cracks along tile/wall joins that needed fixing. In the end, I simply left a couple of small items involving paint finishing because it was time to call it done. They still need to send the final bill with my contingency returned. Now comes the interesting part, measuring how well the improvements we made work.

I have one data point already. Usually for the month of April our electricity bill showed something like minus 6 to plus 12 kwh usage, depending on the amount of sun. This year, we had a whopping  minus 500+ kwh, the impact of our new, more-than-twice-as-large solar PV system. Since we don't yet have our Nissan Leaf, the power is simply going back into the grid. We've just about eliminated the big bill from Feb. when we had to turn the electric floor heating on in the sunroom and upstairs bathroom over a weekend to reduce the amount of moisture from wet drywall mud and we had no solar panels. Unfortunately, the Leaf won't show up until July so we will have a couple more months of large surpluses before we start balancing out.

Naturally, the solar thermal hot water system is cranking too. I turned the temperature down on the tank to 130F to avoid damage to the Stiebel-Eltron electric on demand hot water heater. The company claims it is rated up to 131F. I am wondering if I can instead simply turn the electric hot water heater off for the summer and keep the solar thermal tank at 180F, or if that temperature will damage the electric heater when it is off, but I probably won't try it because the Stiebel-Eltron was expensive. Not that it matters for the water we use. The mixing value brings the temperature down to 120F anyway, but keeping the tank extra hot reduces the overheating strain on the heat transfer fluid, and reduces the probability that a couple days of cloudy weather will reduce the tank temperature below 120F where the electric on-demand heater will cut in. I still need to reinsulate the tank, since the plumber destroyed the fiberglass batt blanket I had installed. I am planning on using aerogel insulation. Should be interesting, aerogel is a new material with some promise, but still pretty expensive. Fortunately, I don't need much for the tank.

In a few weeks, I want to write a retrospective about the job, and also do a piece about reinsulating the solar tank with some pictures I'll probably also have something to say when our Leaf arrives. However, inevitably, the frequency of my postings will be reduced now that I don't have much to blog about. Thanx to all my loyal readers who have pushed my page views up from single digits to low double digits.

Sunday, May 1, 2011

New LED Lights

One of my very first posts (here, published in November, 2009) was on a new LED light bulb. Though it was advertised as a 60 watt equivalent, it is 40 watts at best. These bulbs being what they are (namely, that they last 50 years) I still have both bulbs in light fixtures in areas that don't require much light.

Last weekend, I was busy collecting track light fixtures and bulbs for our new track lights at Home Depot and I ran across new LED bulbs that are also rated at 60 watt equivalent, in a indoor spotlight form factor.  These bulbs are, like the ones I bought 2 years ago, not cheap: $50 apiece, but they are supposed to last 50 years, for $1/year of light. Contrast that with CFLs, which run around $10 and are supposed to last for 5-8 years, for around $1.25-$2/year, and the LED lights seem a relative bargain. But, having been once burned, I was twice shy so I took the plunge on three: two large spots and one small one.

The large spots are Ecosmart brand, marketed by Phillips but manufactured by Cree:
 Unlike the Pharonx bulbs, these have a large plastic fitting around them, maybe a heat radiator?:
Here you can see it installed in one of the track light heads:
The bulbs might be ecosmart, but the way they are delivered was ecostupid. Here's the trash that was left over from one bulb:
I also bought a small spot, equivalent to a halogen bulb, for a pendant lamp for the upstairs front bedroom. Here you can see it next to the halogen bulb it replaces:
The halogen bulb is rated at 50 watts while the LED is rated at 5, for the same amount of light.

For the rest of the track heads, I bought a discount box of CFLs:

Strangely enough, I have to say I like the CFLs better. Contrary to what most people say, the light they give off is softly diffused and slightly yellowish, while the LED light is white and glaring, like normal halogen or incandescent spots. Since we use  spots through out the house, not having them glare into your eyes when you happen look their way is important. CFLs don't seem to glare as much.

When I was done with my task of separating the bulbs from their packaging material and installing them, I was left with a big pile of trash:
That's three subpiles: film plastic,  thicker plastic bubble wrap, and cardboard.  Theoretically, it is all recyclable and we have good recycling in our town, but did they have to include so much?