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cousinbirgco
Joined: 15 Aug 2008
Posts: 141
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 Posted: Sun Feb 01, 2009 6:47 am Post subject: The Saskatoon Super-insulated House |
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Not sure if this research article was posted before
but I thought it was a good review of the potential
benefits of a low energy, super-insulated house with
an emphasis on green and sustainable
building features. There is also an overview of lessons
learned and cost vs. payback which is informative.
The Saskatoon Super-Insulated House
Dumont (2000) described his family super-insulated, two-storey, four bedrooms, 245 m2
(2640 sq. ft.) house (excluding basement), built in 1992 in Saskatoon, Saskatchewan (52°
north latitude). The house was described as the best insulated in the world with the lowest
heat loss coefficient per square metre of floor area of any house anywhere. Dumont built
the house as a model for energy efficiency and sustainable construction that minimizes
energy use, uses renewable energy sources and recycled materials, and generally
minimizes the impact of the house construction and operation on the environment.
Dumont argued that using extra insulation is a simple, effective way to reduce energy
consumption and thus reduce fossil fuel consumption. Because insulation has no moving
parts; it will last indefinitely provided it is protected from the elements with proper
vapour and weather barriers.
In a Saskatoon climate is characterized by an average temperature in January of -18°C
(0°F), annual heating degree days of 10 900 (base 65°F), 2400 hours of bright sunshine
each year, and a winter design temperature of -34°C (-30°F).
The energy efficiency features included the following.
The building envelope included extra insulation compared to the conventional RSI-3.5 (R-20)
value. Blown-in cellulose insulation was used because of its green characteristics. The attic
has RSI-14.1 (R-80), the walls (including basement walls) RSI-10.6 (R-60), and the basement
floor RSI-6.2 (R-35).
The wall assembly included double 38 x 89 mm (2 x 4) stud walls (400 mm/16 in. total
wall thickness) to accommodate extra insulation. 6-mil poly air and vapour barrier placed
on the warm side of the insulation. Blown-in cellulose insulation in the stud space. The
double wall thickness with high-density cellulose insulation increased the wall mass,
which increased the thermal mass of the wall and reduced noise transmission.
PERD-079: Task 2 - Literature Review 63
Triple-glazed windows (about RSI-0.9 (R-5)) with two low-e coatings, argon gas fill, low
conductivity spacer bars, and wood frames were used.
The injected cellulose insulation made the building envelope more airtight as compared to
using fibreglass insulation. Additional measures ensured good air tightness of the building
envelope. All joints in the air/vapour barrier were carefully sealed with acoustical sealant; the
rim joists were wrapped with Tyvek® that was sealed to the poly. The blower door test result
for the house was 0.47 ach at 50 Pa. The Canadian R-2000 standard is 1.5 ach at 50 Pa.
Indoor air quality features included the following.
A balanced heat recovery ventilator (HRV) included a high-efficiency double-core plate airto-
air heat exchanger. The HRV unit was run continuously at 100 CFM (47 litres per second)
to ensure a high indoor air quality.
Dry basement systems prevent mould and mildew growth. Installing exterior perimeter water
drainage and proofing, and insulating the floor slab (RSI-6.2 (R-35)) accomplished this.
Particleboard, OSB, wall-to-wall carpets, and vinyl flooring were avoided to avoid off
gassing of volatile organic compounds (VOC). Douglas fir plywood for the sub-floor,
solid hemlock fir joists, and prefinished solid oak strip and ceramic tiles were used for
flooring. Kitchen cabinets and vanities were birch plywood and solid oak. Low-VOC
paints were used.
Green features included the following.
Scrap gypsum was added to the interior walls to cut down on landfill waste and provide
additional thermal mass, which helped moderate the temperature swing in the house caused
by solar gain. In summer, the flywheel effect of the walls’ thermal mass kept the home cooler
during the heat of the day and warmer during the night and early morning hours.
No air conditioning was needed, because of the fenestration design and overhangs on all
the south windows that limit overheating during the summer period. Also, efficient
appliances were used to reduce internal heat gains. Compact fluorescent and T8 lamps
were used for lighting. Shiny reflectors were used over the kitchen light to enhance
lighting quality.
Decorative shutters on the smaller north-facing windows gave the appearance of larger
windows without the heat loss and poor solar performance that accompanies large north
windows during the coldest part of the winter.
The house was oriented so windows faced south for passive solar gain. An active solar
hot water system with 15.6 m2 (168 sq. ft.) of selective-surface liquid solar panels had a
low-cost wood-framed, EPDM -lined tank, which holds about 5300 litres (1400 US
gallons) of water. This large water tank improves the year-round efficiency of the solar
collection. The hot water in the tank is used to heat the domestic hot water and also heats
the house. This operates via a water-to-air heat exchanger within the forced air furnace,
which uses a brushless direct current fan motor. The fan provides about 800 cfm (376
PERD-079: Task 2 - Literature Review 64
L/s) of airflow using 110 watts of fan power. Additional heat is available through five
electric baseboard heaters located around the house
Water efficiency measures included low-flow showerheads, a variable-water-level clothes
washer, and low-flow toilets. For landscaping, drought-resistant vegetation replaced a
conventional lawn at the front. Collected rain and snowmelt run-off from the roof to use for
irrigation.
Recycled lumber was used in the construction with polyethylene lumber on the front and
back stairs. The polyethylene lumber was manufactured from recycled plastic waste.
To assist with ongoing recycling, a special chute under the kitchen sink directs metal and
plastic cans and bottles to a large container in a closet in the basement. The container could
hold about six month’s supply of cans and bottles. The cans and bottles are then taken to the
recycling depot. A composting container made of recycled polyethylene was conveniently
located near the garage and used year round.
Features that reduced the embodied energy of the structure construction considerably
included using cedar shake rather than an asphalt shingle roof, wood flooring rather than
synthetic wall-to-wall carpets, preserved wood instead of concrete basement walls and
floor, and cellulose insulation that is much less energy intensive than fibreglass.
Lessons learned in building an energy-efficient home included the following.
The incremental costs for the energy efficiency and water efficiency measures, in 1992,
amounted to about C$13,000 and the annual energy and water savings amounted to about
C$800, giving a payback period of about 16 years, or an annual return of about 6.2% after
taxes. Over the seven years (1993-1999), the total energy consumption averaged 15 300 kWh
per year, or 46.9 kWh/m2 per year (14 900 Btu/sq. ft. per year). The average energy use in
Saskatchewan is 300 kWh/m2 (95 000 Btu/sq. ft.).
A low energy house does not cost much more than a conventional one. For a well-insulated
house, the space-heating source can be centralized and there is no need to place a heating
source under each window. This reduces the cost of the distribution duct system of warm-air
heating systems. A rectangular two-story house is a lot easier to heat than a sprawling
rancher. Good indoor air quality in a new home could easily be achieved by avoiding use of
polluting materials, such as carpeting and particleboard.
Dumont (2000) concluded that if a similar house is built in a milder climate, such as that in a
coastal city like Seattle, it would probably be a zero-energy, space-heating house. |
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csintexas
millennium club
Joined: 06 Feb 2006
Posts: 2166
Location: USA
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svenglezz-ASMEIL
Joined: 18 Nov 2004
Posts: 99
Location: Toronto
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| Posted: Sun Feb 01, 2009 12:25 pm Post subject: |
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The 1 year electricity consumpiton chart.
Note a few things.
1 Electric Heaters (uhm for what?)
2 Elect. Water Heater (uhm why?)
3 HRV (hmmmm)
Plus does this home have a/c ? (condenser) and the energy for this?
So in short if you replace the heating/cooling and dom. hot water system from primarly ELECTRICAL then this is cut in 1/2.
Not to mention if you insall a ground soucre heatpump system even more savings.
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csintexas
millennium club
Joined: 06 Feb 2006
Posts: 2166
Location: USA
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| Posted: Sun Feb 01, 2009 8:47 pm Post subject: |
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Yeah I don't know why they would use resistance heaters. It could be something prevents them from using a ground source heat pump. They do have a solar water heater that supplies some of the heating so I think that the electric is a back up. Well I guess I am also a skeptic of HRV's also but it is in a very cold climate and as pretty tight.
| Quote: | the total energy consumption averaged 15 300 kWh
per year, or 46.9 kWh/m2 per year (14 900 Btu/sq. ft. per year). The average energy use in Saskatchewan is 300 kWh/m2 (95 000 Btu/sq. ft.). |
also, this sounds fishy
If it uses about 1/6 the amount that an average house uses this means an average house uses about 90,000 kwh per year at .18 per kwh this would come to about $16,000. per year vs. $2,700 which would have paid the investment back in about two years. But it was stated in the report that the additional expense was recouped in 16 years so I think those numbers are incorrect.
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http://bcshdb.blogspot.com >
The B/CS Home Design Blog |
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svenglezz-ASMEIL
Joined: 18 Nov 2004
Posts: 99
Location: Toronto
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| Posted: Mon Feb 02, 2009 2:54 pm Post subject: |
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Ya' very good points.
Maybe the wife was cranking the heat and taking baths every day 
(ouch) takes a shot from wife
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