Ecohome's Kenogami House wins Home of the Year Award
The Kenogami House holds the highest LEED score achieved in Canada (106), a Net Zero Heat rating of 15 kWh and a Home of the Year Award from Green Builder© Media for Best Resilient Design.
Along with its unprecedented achievements, the Kenogami House continues to act as a laboratory for resilient, cold climate building practices. Through software energy modeling it was determined that the Kenogami House would likely require 14.6 kWh of heat per square metre per year, but its actual performance seems to be even better.
What we have learned this first winter is that 4 hours of heat captured from the sun can provide approximately two days of comfort. Regardless of outdoor Celsius temperatures in the minus twenties and no supplementary heat, with a day of full sun the Kenogami House has achieved interior temperatures as high as 26.9 °C (80.5 ºF), a temperature where many people will have already turned on their air conditioners.
During average winter conditions of temperature and cloud coverage for the Saguenay region of Quebec, the Kenogami House had its heating system turned off for a 10 day stretch in February, yet maintained indoor temperatures in the mid 20s (°C) and dropped only to 20.4 °C after consecutive overcast days.
To balance temperatures through the home, unheated water is pumped through the concrete slab floor to help transfer the warmth of the sun from the southern exposure to the north end of the house, also making sure rooms exposed to the sun do not overheat.
The following table charts the temperatures over the course of a 4 day period with variable temperatures and sun exposure.
|Date||Time||Ext. Temp °C||Int. Temp °C||Slab °C|
|Feb 17 (full sun)||8:00 AM||-20.9||22.2||19.5|
|Feb 18 (mix of sun &cloud)||7:00 AM||-24||22.6||20|
|Feb 19 (80% overcast)||6:30 AM||-3.1||20.8||19|
|Feb 20||6:00 AM||-12.3||20.4||18.5|
While the Net Zero Heat program designs from the benchmark of complete passive solar heating, this is not a rigid target. Depending on climate and other considerations (such as with the Kenogami House), achieving zero heat demand is not always the best use of resources.
Regardless of your building envelope, in terms of resiliency we would always recommend an additional heat source to ensure comfort in even prolonged overcast conditions.
However, at levels of thermal performance like that of the Kenogami House, a centrally located single heater of approximately 2100 w (similar to a powerful hairdryer) would likely be more than sufficient during the most extreme cold, and for the most part not be used at all.
The building envelope:
- 91% of glazing is south facing
- Triple paned argon filled fiberglass framed windows > R4.5
- Ceiling: 3" Polyisocyanurate and 36" of cellulose > R151
- Wall insulation: 14" of EPS foam and 7.5" of mineral wool > R 80
- Slab on grade insulation: EPS foam and polyurethane > R60
- 0,57 ACH @ 50 Pa ( Air Changes per Hour at 50 Pascals of pressure)
- 5400 w photovoltaic solar panels with battery backup
- Radiant floor heat powered by a high efficiency gas boiler
- 84% efficient Zehnder Novus 300 ERV (Energy Recovery Ventilator)
While similar in concept, an ERV (Energy Recovery Ventilator) was chosen over an HRV (Heat Recovery Ventilator), as they are particularly well suited to extreme northern climates.
Air is able to support less and less water vapour the colder it gets, and an ERV extracts that energy rich moisture from interior exhaust air before it is ejected. This helps keep indoor humidity at more comfortable levels, along with retaining the added heat energy (known as 'latent heat' that is contained in vapour compared to dry air.
The ERV system will continue to offer energy savings in summer months, as removing moisture from exterior air before it is injected into the home makes high temperatures more bearable, while also reducing the load on air conditioning systems. In this case, the ERV in conjunction with the high R value building envelope and passive cooling design will likely make air conditioning unnecessary except in extended heat waves with high night time humidity levels.
Life in the Kenogami House
As homeowner and part of the Ecohome design team, Alain Hamel will continue to experiment with the latest energy systems to further enhance the performance and thermal comfort of his home. The next system to be installed will be an air-to-water heat pump which will serve as an air conditioner. In effect this will prevent the home from overheating during consecutive sunny days in winter, while producing hot water essentially for free.
Heat extracted from indoor air will be transferred to the existing hot water tank, allowing excess daytime heat to be used for domestic hot water use or released into the slab floor to balance temperatures through the night.
Being considered for the future is the addition of a phase change thermal battery that will work in conjunction with the air-to-water heat pump, which can store approximately 10 times the heat by volume as water.
As this home was designed for resiliency, among other notable features it includes an underground 2000 gallon rainwater harvesting system which feeds showers and toilets during all seasons, being charged in winter by melt runoff on warm days.
Durable, low maintenance design:
The true cost of a home can only be determined when factoring in its expected lifespan and the maintenance that will be required along the way. To that end, both interior and exterior surfaces have been designed to endure. The polished concrete floors will require little maintenance, as will exterior surfaces of metal, stone and cedar.
The goal during the design of this home was to make it as durable, efficient and autonomous as possible. Many of the design features are original, and these technologies very new to the market. It is for these reasons that we consider the Kenogami House a living laboratory of resilient building technologies that will continue to be fine tuned, and hopefully offer insight and inspiration to others.