Net Zero (house and two cars) in Minnesota

Hey all, I would love to hear any suggestions, ideas, or discuss any aspects of our net zero home, currently under construction.

Our website is at Driven to Net Zero - Home
The direct link to the blog is Driven to Net Zero - Blog

The definition of "net zero" we are using is a house that produces as much energy as it uses on an annual basis. We have, however, added a twist.
The twist is, that we include the energy we use to drive our two electric cars.

We are having a lot of fun, and I have learned a lot about building a house. We are at about the halfway mark this week.

Geothermal wells are in, tubing is roughed in to the mechanical room.
Solar array is planned, but not yet installed.
Insulation started last week and concrete is curing.

I'd be happy to answer any questions here, or at the site.

 

Net Plus would be nice.
I believe some countries are moving in that direction (requiring net zero).
I suspect we will get to net plus when we trade in our Model S for a Model 3.

 

We have reached out to a number of media outlets.
Upon completion we plan to have the house on a number of house tours as well as print and radio.

 

Well, it has been a while, many more delays than we expected, but the house is nearing completions! About 6 weeks to go.

But the solar is being installed!

Racks are up on both house and garage. Wiring and optimizers are in place for the house.
Two inverters are in place on the outside of the house, and one is being installed downstairs.

Unfortunately, we have rain and thunderstorms the rest of today. Monday we should see more activity.

 

Today was a very big day!

It started with a power outage for the neighborhood
Work at the house is moving forward, but slowly, we are still at least 3 to 4 weeks out.

However, at about 1pm today, our utility installed our production meter and a net metering meter. Our panels are producing and feeding into the grid!
We don't have internet yet, as soon as we do we will be measuring the energy draw of a number of parts of the house (HVAC, sump pumps, EVs, large appliances, etc).

 

Well, we have been in our house about 6 weeks now.
Our energy monitoring setup has been in place about 3 weeks.

Just like the Prius' instant mpg feedback helped me be a more efficient driver, this system (eGauge) has already helped me with energy efficiency around the house.
One of the bigger surprises was that our LED light strip is drawing 80 Watts. While I knew it was a long strip of lights, I didn't realize it was drawing that much until I saw it on the graph.
We are much more careful about turning that off when not needed

I have more details about the eGauge system in my latest blog at Driven to Net Zero - Blog

It is rather cool to see how the morning shading affects our different solar arrays (3 inverters). Each is represented in the image by one of the dashed green lines.
The lowest generating solar inverter on the left of the graph are panels on our garage roof. These have some shading in the early morning (shaded by our house roof). Just after 9:15 that shade starts disappearing and it quickly takes the number 2 spot.

I'm hoping to set up a system that will set synchronize the car charging with the amount of solar energy being generated.
I have a couple of friends that have already done this, so it shouldn't be too difficult.
Above, the bulk of the energy draw starting about 9:20am is me charging my car.

One of our inverters though is intermittently resetting itself.
This was happening so often that inverter was only generating 80% of the power it should have been.
After a firmware upgrade, it is up around 98%, but we are still trying to nail down exactly what is happening and why.

 

Well, the last architect event this year is happening Thursday, and with winter approaching it will soon be time to turn on the heat.

In another thread, which I can't find at the moment, someone was very sceptical of using electricity for e geothermal pump being efficient.
I believe it was off topic there, so if you come across this, let's continue that conversation here.

For anyone, in general, we came to the conclusion the ground source heat pump was our most efficient route after considering:

1) We didn't want to use any natural gas.
2) Air to Air heat pumps don't work very efficiently in Minnesota winters.
3) Our house is designed to be extremely well insulated/sealed.
4) With the 'passive solar' design, much, if not all, of our heating on sunny days is taken car of naturally.

Our ground source heat pumps supply all of our heating and cooling needs. No backup system is required for those cold MN winter nights.
Waste heat from the geothermal pumps is shunted to a preheat water tank for our domestic hot water.

To test out the system, I switched in to 'winter' mode yesterday.
The standby power draw seems to be 50Watts.
Of course, until the system is actually heating, we won't see the peak draws. This weekend we are expecting the first snow of the season, so we may need some mechanical heating then.

 

Well, I messed up there...

Seems when I turned the pumps over to heating mode, a group of formerly dormant in-floor sensors and simple thermostats turned on.

I didn't even think to check on these, and they were set between 70 and 74 degrees.
The temp in the house is generally in that range, but different zones were calling for heat, not from our programmable thermostats that measure the air temp, but the simple static thermostats that measure each zones floor temps.

Now that those are correctly set, the standby power on the thermostats is 9 Watts.

First snow yesterday, and all week is supposed to be in the 30s (0-5C). With only one sunny day in the forecast, this week should be the best test we have had yet!

 

I'm not sure what you have seen

However, here is a link to one of the site's pages that discusses it a bit: HVAC - Driven to Net Zero
And here is a blog entry about the insulation, heating tubes, and geothermal: Category: GeoThermal - Driven to Net Zero

In any of the blogs, over on the right side of the page there are tags for different aspects of the house (e.g. Geothermal, thermal mass, solar, etc).

The only work I personally assisted with was some of the electrical work, and it wasn't much beyond running wire and stapling it.
So my ability to answer in depth questions about the engineering process may be limited, but I will do my best