Archive for the 'Electrical' Category

Our new energy monitor

Photo of eGauge in box

The setup

As you can see in the photo above, we have 2 new eGauges. Each monitors up to 12 circuits, for a total of 24. When you count 2 lines in, solar and several circuits that have double breakers pulling unbalanced loads, that ends up covering 20 individual things we can now monitor. We were previously monitoring only 7 circuits plus solar and power from the utility.

We’re now monitoring the kitchen refrigerator, basement freezer, ventilator, ventilator pre-heat, barn, the backup electric resistance units in the bedrooms and living room, and a bunch of other circuits including the one we charge our plug-in hybrid.

We chose the EG3000 model without the HomePlug AV. Our router is very near the electric panel in the basement so it was easy to wire it directly using ethernet cables. The ethernet model requires a separate enclosure. You can’t put it in the panel box. This is fine because there is isn’t much room in the panel box, especially after you install 24 CTs and a load of twisted spaghetti wire (see above). My electrician installed this small box next to the panel with all the wires running through conduits. I’m going to cut a piece of clear plexi to fit over the box so you can still see everything inside, but keep the dust out.

The install

The eGauge install was fairly similar to the eMonitor. You need to power the monitor devices directly from the breakers in the panel box, and you need to keep track of which lines you are monitoring. My electrician figured it quite easily, although he installed all the current transformers (CTs) in the opposite direction. Thankfully this doesn’t really matter as long as you are consistent in the direction you install them.

The cost

The 2 eGauge units plus the CTs and shipping worked out to $1,282. Our electrician charged us about $400 for the physical install. I did the configuration and spent several hours messing with the settings to get everything working correctly. The documentation is not great, but I figured most of it out. Having some prior experience with an energy monitor (we’re now on our third) definitely helped.

I don’t remember how much we paid for the eMonitor 2 years ago. I seem to recall in the $600 range for the 12 circuit wifi model, plus another $400 for install. It looks like you can now get a 24 circuit ethernet connected model for $700 plus the 2 year subscription fee, which for us was about $180.

So why did we switch?

1. No yearly licensing cost

I absolutely enjoyed the data that came out of our eMonitor (see our post 2 years ago), but I deplored their architecture and business model which required me to pay a subscription fee every two years to have access to my data on their servers.

eGauge has no licensing fees and stores its data right on the box, at 1 minutes resolution for the first year and 15 minute resolution after that up to 30 years.

2. Data quality

I’ve been tinkering with some new analysis techniques that required minute resolution data. So I downloaded 2 years worth of minute data from my eMonitor. This was not a pleasant experience since they only allow you to download 2 weeks of data at a time, the data files are large. Then I proceeded to look at the data and try to recreate the hourly data from the minute data. This should be an easy exercise, but I found that there were lots of little gaps in the data. I was not able to fully recreate the hourly data I had originally downloaded. After numerous emails with their service desk, they stopped responding.  I don’t think they could explain the gaps. I don’t know if the problem was hardware, or data was lost in translation, but it didn’t give me a lot of confidence in the device or service.

I spoke about this issue with a few people at the Better Building by Design conference in Burlington, VT back in February. The Efficiency Vermont booth was demonstrating some energy monitoring case studies and had good things to say about the eGauge. I have a huge amount of respect for the Efficiency Vermont organization. Lots of smart folks there.

3. Make-ability

I enjoy building stuff and tinkering with different ways of analyzing and visualizing our energy usage.

With the eMonitor, I downloaded our data from their servers once a month. It wasn’t easy enough to do in any shorter increments and I wasn’t going to apply for a developer license to access their databases directly.

Since the eGauge data is on the box in my basement*, I can access realtime data through the built in web interface or through a simple API. This is awesome for makers. I’m looking forward to building a new realtime interface to view our energy data.

*Since the data is on the box in my basement, I’m setting up an automatic backup.

4. Customizable

the eMonitor may be different now, but when I bought it 2 years ago, it came as a kit to monitor several different sized loads. We ended up not using one of the monitoring slots because we didn’t have a circuit I wanted to measure that matched the monitor amperage.

eGauge lets you mix and match components. I picked the number and size of the CTs and the type of monitor configuration to match my setup.

Screenshot eGauge 6hr view

That’s it, go out there and measure stuff.

Why we bought a Plug-in Hybrid

photo of Prius

If you remember one of our early solar posts when building the house, we initially assumed that solar was going to be too expensive for us. Then we ran the numbers and found that the rate of return was actually quite attractive over the log run.

Same goes for our new plug-in hybrid. We had been a one car family since Jill and I met. Our four-wheel drive Ford Escape was both our commuter car and utility vehicle. We made multiple moves in that car. We carted goats and chickens and guineas in that car. We transported a year’s worth of hay. We hoped the Escape would carry us a few more years, but at over 200,000 miles our trusty steed was starting to cost us more in gas and repairs than buying a new car.

We now have a truck to haul goats and other farm trappings when needed, so Jill started researching commute-friendly cars. She drove three hybrids, Honda Insight, Toyota Prius and Ford C-Max. The C-Max had the nicest interior and was more similar feeling to the Escape, but was the most expensive and the mpg reviews were mixed. The Insight had a great price point, but had the worst mpg estimate and interior feel. So we focused on the middle-priced Prius which had the best mpg estimates and a good track record.

With our current net metering plan, it’s better for us to use the excess than sell it back to the utility which pays us very little. It initially looked like a plug-in hybrid was out of our price range (even with federal credits) but when I added up the miles: 19,500, the gas: 970 gallons, and gas dollars: about $3,600 a year, I realized the extra savings in gas might justify the higher cost.

Here’s the breakdown…

The Escape was averaging about 20 mpg. The regular Hybrid Prius averages 50 mpg and would save us 580 gallons of gas and $2,150 per year. Toyota says the Prius plug-in gets roughly 95 mpge (that’s miles per gallon plus electric). We test drove the plug-in for a few days on back country roads and found it was closer to 85 mpge. The plug-in component gives you an extra 13-14 miles before the hybrid engine kicks in.

We estimated conservatively that 70 mpge would save us 690 gallons and $2,560 per year, but use approximately 1,400 kWh per year. That would cost us about $210 in electricity charges if we were paying for electricity, which means we would only be saving $2,350 per year in gas.

The regular Prius is $24,995. Toyota had a special offering interest free loans up to 60 months. So $25k/5 = $5,000/year plus $1,450 in gas equals $6,450/year. Now remember, we were paying about $3,600/year for gas, and $2,000 or more per year in maintenance. So we’d be paying an extra $830/year for a new car.

The plug-in version is $8k more. $33k/5 = $6,600/year. But in addition to 0% interest for 60 months, they were also throwing in a $4,000 rebate for plug-ins. There’s also a $2,500 federal tax credit. That brings the price down to $26,500, only $1,500 more than the regular Prius. That works out to $5,300/year plus $1,030 in gas, plus $210 in electricity equals $6,540. That’s about $90 extra per year for the plug-in, assuming we paid for electricity. Take out the electricity (because we produce excess electricity per year) and the plug-in is cheaper than the regular Prius.

Of course we didn’t start at the $33k price, Jill bargained them down. After rebates and tax credits we’re paying about $100 less a year for the plug-in over the regular Prius. So we are basically paying about $520 more per year (not counting electricity, and assuming gas prices stay the same) for a new car that is easier on the environment. If we get closer to 85 mpge then we will only be paying $330 extra per year. If/when the price of gas goes up, we save more.

The only down side. The Prius is definitely not going to make it up our driveway some days in the winter.

Last update of 2011

Lot’s of news this week. We got our Certificate of Occupancy (C.O.) on Wednesday! We can officially occupy our home this weekend.

We worked like crazy last week and over Christmas to finish all the odds and ends for the final inspections. We finished all the electrical Wednesday, 12/21, and had the final electrical inspection the Friday before Christmas. Our water test results arrived Christmas Eve. We spent the rest of Christmas weekend finishing up the porch railings and temporary stairs for the final inspection on Tuesday, 12/27. Our inspector gave us the thumbs up and faxed us the C.O. on Wednesday.

But wait, there’s more… Our contractor Warren entered the Energy Star program with our house. In order to complete the program and qualify under the 2011 rules, we had to get our final inspection and blower door test before the end of the year. This happened Thursday, two days before the end of the year. Final blower door result was 131 cfm, an improvement of 28 cfm from the shell test we did back in September. We’ll post more information on the Energy Star process next month when things settle down. It’s the only certification we’ve chosen to do for the house.

Our kitchen counter tops also arrived yesterday and were installed. The counters are Cambria Quartz (color: White Cliff.) We chose a manufactured quartz counter because we wanted something durable and low maintenance. And we chose Cambria because it’s the only American company manufacturing quartz counter tops. It looks fantastic.

And we generated our 5th megawatt Thursday. It took us almost 60 days to do it. That’s 5 megawatts for half a year. The system went online June 2nd.

We have a few finish work projects to complete. As we were running short on time, Jill found tile contractor, Chad Greenslet, out of Bennington to finish our shower tile job. He installed the Schluter and tile in 2 days, but ran out of tile. We thought we had ordered extra, but somehow miscalculated. The extra tile arrived today, so that project should get finished up next week. Jill is also working with a local glass supplier to install a frameless shower door.

The site-cut maple intended for our stairs is still drying out in our basement. At some point soon we’re going to have to decide if it will be ready in time, or if we should purchase other material for the stair.

95% of the trim is installed. The holes have to be filled and cracks caulked before it gets painted. Doors have to be painted too. Jill is hoping to get the two bedrooms finished this weekend so we can start moving some stuff into them.

Also, a few pieces of siding trim for the basement entry have been sealed and are awaiting installment.

But that is about it. We’re down to the final punch list. We have to be finished in two weeks for the mortgage appraisal. That is our other task – converting our construction loan over to a mortgage. More on that process soon as well.

Solar continued…

Last week we saw a lot of rain, making for a slippery roof and slowing down the solar installation. They were only able to finish wiring the inverter to the main panel and install the first set of rails for the lower row of panels.

This is their first installation on our type of metal roof. See our post describing our metal roof. They were concerned that the rib was a bit taller, (1 3/4″) than they encounter on ordinary folded metal roofs. They called the manufacturer (ASP) and decided to put an S-5 clip on every rib, as opposed to every other rib. The ribs are approximately 18″ apart.

Progress should be quicker now that they have the first set of rails up. Hopefully they’ll get the next set of rails and maybe a few panels up on the next clear day.

Electrical and some landscaping

We’re trying to do as many things inside as we can these days due to spring rains.

The main activity has been installing electrical boxes and running wire. We want to be ready for the solar installers, who may begin their work later this week. We got the main panel in last week and are now working on installing wall outlets and light fixture boxes. We’re fitting our exterior wall outlets inside poly boxes to simplify our air sealing details. A little foam where the wires pass through and some sealant on the edge of the box when we install the drywall should help keep interior air out of the walls.

In the landscaping department, we received the 3 apple trees we ordered from Trees of Antiquity this past weekend and planted them on the hill behind the house. Our mini orchard consists of a Macoun, a Jonathan, and a Newtown Pippin—all organic NY state heirloom varieties. Then we surrounded them with deer fence and a 4 stage electronic surveillance system designed to thwart all but the most devious of deer. (Just kidding about the surveillance system.)


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