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Rob Dumont

posted Feb 1, 2011, 3:07 PM by ASHRAE Saskatoon   [ updated Feb 1, 2011, 3:29 PM ]
Can you tell us more about the VerEco Net Zero Energy Home in Saskatoon?

The VerEco Net Zero Home in Saskatoon was opened in October of 2010. The house is on display at a local Museum until August of 2011, and then it will be moved to its final site and be placed on a basement. The house is a modest bungalow in size, with 1440 square feet on the main floor. Here’s a photo of the house.
Figure 1. VerEco Net Zero Home Exhibit in Saskatoon

What are some notable features of the Net Zero Home?

1. The Net Zero home is likely the coldest NZ home in the world (In location, not in interior temperature). To my knowledge, no one in a colder climate has built such a house. Less than 1% of the world’s population lives in as cold a climate as in Saskatoon. If it can be done in Saskatoon, it can be done anywhere in the more populated and warmer parts of the planet.
2. The home may have the best insulated residential attic in the world. The attic has an R value using cellulose of about 110 in English units (RSI 19.5.) I used to think that my house, with R80 in the attic, was at the outer limit. Not so any more.
The walls are double stud walls with about R60 blown in cellulose insulation. 
3. The flat plate solar thermal panels are mounted vertically on the south wall. (Saskatoon is located at latitude 52 degrees North.) In addition some evacuated tube solar thermal panels are located vertically on the front of the deck on the west edge of the south side of the house. (These evacuated tube panels have not yet been connected to the heating system.) These locations for active solar panels give more design freedom, although at a penalty in energy performance.
4. Additional thermal mass is present in the floor tiles. The floor tiles are prefabricated concrete tiles with a thickness of 1.25 inches. The tiles serve three purposes—they provide a finished floor, they help moderate temperature swings from solar gains during the heating season, and they also help moderate temperature swings in the summer.
5. The house was pre-fabricated off site and moved in one piece to the exhibit area. Saskatchewan has quite generous rules as to the size of new homes that can be transported, and this 1440 square foot house was readily moved. For a short video showing the move, have a look at http://www.youtube.com/watch?v=cp34vBuRshQ
6. The house is open six days a week for 10 months at a popular museum site. Especially important are the elementary school tours, as kids in Grade 7 science are taking material on energy, and the house tours will help a lot in explaining principles of energy and water efficient design. (We haven’t had all that much success educating adults in North America about sustainable housing, so perhaps getting people at an earlier age will help.)
7. A weekly series of lectures given at the house are being videotaped and available on Youtube. Go to http://www.verecohome.com/expertseries/ for a listing of the talks that are available.
8. A relatively inexpensive device (about $280 plus shipping) called a TED 5002-G allows one to monitor the house electrical consumption and photovoltaic generation over the internet. An electrician or experienced electrical person is needed to attach the TED unit to the main electrical panel. A view of the Dashboard output from the VerEco Home is shown on the wall mounted LED TV hooked to a computer in Figure 2.  The TED unit collects historical data as well as instantaneous. 

Figure 2. Interior View of the VerEco Home showing the wall-mounted LED TV with the TED Dashboard.

Figure 3. Dashboard for the TED-5002 G Unit

Figure 4. Meter showing the instantaneous electrical energy consumption of the house.

The TED unit also will graph the energy consumption and production for the house. In Figure 5 a graph of a 7 day interval is shown.

Figure 5.  Graph of hourly energy consumption and PV production at the VerEco Home for January 12 to 19, 2011.

As can be seen from the graph, there is a period on January 15 and 16 when the energy consumption increases dramatically. During these periods, a worker was outside on the temporarily hoarded front porch, and was using a 220 volt construction heater. The high consumption for those periods is evident from the graph. The light coloured bars below the 0 axis are the PV production. The house has a 4.4 kW peak PV system tilted at an angle of 62 degrees from the horizontal. Note that between January 14 and 16 the PV production was minimal—this was caused by a combination of cloudy days and heavy snowfall which radically reduced the PV output. On January 17 the panels were cleared off with a roof rake and the PV production resumed. The TED 5002 G greatly helps in tracking the energy performance. 
The house sits on a crawl space, and during the open house there is no insulation in the floor. Thus roughly 2/3 of the heat loss from the house is into the crawl space. As can be seen from Figure 5, the total energy consumption of the house (there are no sources of heat such as a natural gas furnace or boiler) is very modest. (1 kilowatt = 3413 BTU/h).

The key to the outstanding performance of the house is the outstanding energy conservation design. With the greatly decreased loads, the renewable energy sources, 
---passive solar gain, the active solar thermal and the photovoltaic panels--- are projected to generate enough energy to make the house Net Zero in annual energy consumption once the house is moved onto a basement.