Today I finished moving this website to a new server, and reflected back on the journey of building our green home. It has been nearly 16 years since we moved in! How would we evaluate our experience? Which of the choices we made stand out as good ones? What might we do differently? Here's a summary of our key takeaways, with a letter grade for each decision we made:

• Drain Water Heat Recovery: B

  Water comes in from the utility, goes through the drain heat recovery system, and then into the preheat tank for geothermal where it is heated further before going into the main hot water tank. The drain heat recovery is a good idea and for many use cases would be a good investment. But for us, stacking two technologies to preheat water is of questionable value. We have not had problems with our Power Pipe and it's still a cool display piece (as plumbing goes), but we cannot say for sure if it has actually saved us any money.

• Geothermal Heating and Cooling: B+

  We have been very happy with our geothermal system. Unfortunately, in 2019 it developed a slow leak of coolant due to a crack in the coil and had to be refilled several times. The original unit was branded by Carrier, but built by a company called ClimateMaster, which had since been sold to another company. We were unable to source a new coil (it would have just been a refurbished part) and furthermore, the unit was not compatible with more modern controls (e.g. internet enabled thermostats). We also had problems with the water pumps on this unit, and new ones were getting more difficult to source, as more recent models would have required swapping out the flow center as well.

  Therefore, in 2020 (at the peak of the COVID pandemic), we replaced all of the ClimateMaster equipment with WaterFurnace. We also downsized from 5 ton to 4 ton, as in our entire experience with the system it had never reached the second stage of heating or cooling. We have been happy with the WaterFurnace unit, and I have been able to capture a lot of data from its management interface from the various sensors. Fortunately we were able to re-use the wells, but the replacement of the unit and water pumps ran about $15,000 after tax credits. 16 years in and neither unit has either failed to keep up with the heating load (looks like we were right when we declined to have auxiliary heat installed). I gave us a B+ because hindsight being 20/20, we should have just gone with WaterFurnace in the first place instead of saving a few thousand dollars.

• Hot Water Heating: A

  We proactively replaced the hot water tank in 2022 as it was reaching the end of its life. We had no problems with it, but for the replacement we chose a tankless model. We've been very happy with this decision. The combination of the geothermal pre-heating with the tankless system to "finish it off" has reduced our gas bill measurably, especially in the summer.

• Insulation and Air Sealing: A

  The house was built "tight" and we've been happy with the insulation and air sealing performance. We've only had a few power outages that have lasted more than a few hours (thank you underground utilities) and the house has remained comfortable throughout.

• Rain Water Harvesting: F

  This is our biggest regret. We used this system to some degree, but it was quite inconvenient: instead of turning on a faucet, you had to go start the pump, hook a hose to a spigot, and then turn on the water. It was a hassle, and ultimately we stopped using it. In addition, it requires winterization, removing the pump (and then installing it the next spring). We are fortunate to be in an area where water is plentiful, but more significantly, we choose not to water our grass and just let it go dormant. We only really needed outside water for the one week a year after planting annuals. After a few years we just installed regular downspouts, completely bypassing the rain water harvesting system.

• Solar Panels: A

  We have been happy with this investment. According to our measurements, we "broke even" after 8 years (much faster than calculated). Unfortunately our utility ended the $0.25/kWh promotional incentive after ten years, so we are now on a plain net-metering arrangement. Our original panels have held up well and we are still getting good performance even as they age. Our inverter has also held up despite being beyond its life expectancy. The system has required minimal maintenance over the years, which has been a pleasant surprise. The only downside thus far is that the neighborhood birds like to build nests under the solar panels which results in significant accumulation of debris in our gutters, so we need twice yearly gutter cleaning despite not having any large trees nearby. Unfortunately, the triangular panels we used for aesthetics are no longer manufactured, so when it does come time for replacement, we will need to switch to more traditional panels.

• Water Conservation: A-

  In 2021 we had a whole house water monitor installed and it calculates that we use 79% less water than an average family of 3. We're pretty proud of that! The only regret we had is not getting a water softener sooner (this was installed with the tankless water heater in 2022). Our area has very hard water and this likely contributed to the premature death of our first dishwasher.

Today we received our official certificate from the Green Built Home program!

Check out the upper right corner of the middletongreenhome.com main page, and you can see our real-time solar array generation stats!

The folks at H&H solar installed our "Fronius Interface Card Easy" on Monday, which allows real-time querying of the inverter via serial connection. We have a home computer polling the interface for its current power output every 3 seconds, and uploading this data to the website. The day's generation is then calculated from the statistics gathered.

As part of our landscaping, we have added a 1500 gallon collection basin for rain water that runs off the roof. Approximately 1.5 inches of rainfall will fill this basin. A pump will then make the water available for lawn and plant irrigation.  (The pump will be installed next spring.)

The retention basin is outlined and excavated.

Instead of a tank, "AquaBlox" modules and a plastic liner are buried in the ground. This modular system is assembled on-site.

A total of 48 "AquaBlox" are buried.

Once this was completed, this entire setup was covered with gravel and then buried under the sod that was eventually installed.  We will provide more information about this system on the Water Conservation page.

Today, the connection of our solar system to the utility grid was completed.  Madison Gas & Electric installed the second electrical meter and the system is good to go.

For more information about solar energy in general and our solar project in particular, please visit:

Middleton Green Home solar page

Here are pictures of the installation from the beginning to the finish:

The total capacity of our system is 2.7  KW. The inverter is installed in our basement.  The inverter converts direct current (DC) from the solar panels into alternating current (AC) for the power grid. You can see from the side-by-side picture of the inverter next to the breaker box that the inverter is a rather large piece of equipment. And this is one of the smaller inverters available.

Here is the picture of the completed installation.

Today was the third and final site visit for Energy Star.  This is the visit where all requirements are verified, bath fans are checked with the balometer, and the blower door test is performed.  Our results were very positive:

• Bathroom fans all passed (60-80 CFM for fans in powder room and toilet room and hallway bath, and an amazing 120+ CFM for the fan above the master shower).
• Blower door test passed -- we needed 1888 CFM or less for Energy Star qualification.  Our result was about 600 CFM!
• Thermal scans with infared camera showed no areas of concern.

Obviously we're thrilled ... this was a great cooperative effort between Laura and the Ackers to help us achieve incredible results without busting the budget.