Cliff House

Off-Grid Sustainability

Set on a rock formation overlooking a spectacular lake, the Cliff House seeks to enhance the extraordinary surroundings through the thoughtful integration of building elements with the natural assets of the site and terrain. The program called for intimate spaces carefully tuned to the unique views, light, and breezes of the site. Self-sufficiency was a key client mandate as the project was to be located completely off-grid.

The dwelling emerges form a cliff and rests on a base crafted from local granite. A tall central void acts as an anchor that circulates movement, light and air into living spaces that pinwheel and extend into the landscape. Balancing the heavy mass of two interior fireplace cores, cantilevered volumes, flying roofs and floor-to-ceiling glass achieve a lightness of form and work to draw the nearby lake into each interior space. Finely crafted materials including hand-hewn stonework, wood ceilings, and structural board-formed concrete walls define the residence and celebrate the skilled contributions of all tradespeople involved.

Living lightly on the site was important to the owners and the architects were given a strong mandate for sustainability. As a retreat for the family, the desire to become completely self-sufficient and independent from external infrastructure became critical to the design of this off-grid residence. The design achieves this aim by combining passive and active systems. Sustainable design in this case is not divorced from the experiential qualities of the dwelling but enhances the unification of building and landscape.



This design implements passive solar gain and massing strategies that take advantage of the sun’s daily passage and the movement of air through different seasons. During summer, solar shading limits heat gain while operable windows are orientated to utilize natural ventilation. Operable windows in the vertical circulation space create a stack effect to vent hot, stale air above and draw cool, fresh air in from below. Green roofs mediate temperatures and control rainwater runoff while connecting the building foreground with the distant landscape. Optimized glazing and solar orientation in conjunction with the thermal mass of concrete slabs and stone walls form the core of the heating system. A high performance envelope and super-insulated glass work to limit and control heat loss and gain throughout the year. These passive strategies reduce the buildings’ energy load and augment comfort so that the demands on active systems are kept to a minimum.

Two contra-flow masonry heaters (ultra-clean burning) in the fireplace cores take full advantage of the abundant biomass available on-site for supplemental heat. An array of evacuated tube solar collectors use the sun’s energy to heat water that circulates through them and is stored in 10 thermal tanks. This massive store of energy supplies the hydronic radiant floor heating system as well as the domestic hot water supply. An array of photovoltaic panels and a battery bank provide the building with electricity. Electrical loads have been carefully managed and are minimized through the use of energy efficient appliances as well as modern LED and compact fluorescent lighting systems. The building has been commissioned and occupied. We are closely monitoring it’s energy use to make any adjustments as needed.



The 10 kw PV array is metered to allow the occupants to regulate and control their energy use. The Solar hydronic heating system has also been metred and is connected with the back-up propane boiler, allowing for a seamless transition from solar to propane when needed. Our goal was to limit the quantity of stock energy resources to create a home that fuels itself. Since a good portion of the heating system is user based and dependent, the more the building is used the less the back up system is relied upon.

Both the clients and the design team involved are very excited about the ongoing research component of the building.

On a recent sunny November day, outdoor air temperatures were measured to be below 10 degrees Celsius while passive solar gains alone maintained indoor air temperatures in excess of 25 degrees Celsius; at which point venting skylights automatically moderated indoor temperatures. The thermal mass slabs which had spent the day absorbing solar energy would then heat indoor spaces overnight as they slowly released their stored energy.

The design was engineered so that the solar mass storage tanks, when fully charged (one to two days of full solar gain) could provide enough hydronic solar heating energy to last four overcast winter days.

We will continue posting updates to our research findings.

Sustainability Features

  • Program and Spatial Optimization
  • Integration with the ‘Natural Assets’ of Site and Terrain
  • Site Specific View and Vista Optimization
  • Passive Solar Heating (Thermal Storage Mass)
  • Natural Ventilation and Passive Cooling
  • Natural Daylighting
  • High Performance Envelope Design
  • Renewable and/or Recyclable Materials and Finishes
  • Indoor Air Quality (IAQ) and Non-toxic Materials and Finishes
  • Advanced Wood Heating Systems (ie. Contraflow Masonry Heaters)
  • Radiant Heating
  • Heat Recovery Ventilation
  • Solar Hot Water Systems (Domestic and In Floor Radiant Heating)
  • Solar Electric (photovoltaic or PV systems)
  • Wastewater Heat Recovery
  • Low Energy Lighting & Appliances (LED, CFL lighting and Energy Star appliances)
  • Water Conserving Appliances & Fixtures (low flow/ dual flush toilets)
  • Green Roof Systems



Altius Project Team Architecture

  • Architecture: Trevor McIvor
  • Construction Management: Trevor McIvor

Project Partners

  • Construction: Orchard Contracting / Bracebridge - Doug Orchard
  • Engineering: CUCCO engineering + design - Toronto - Christopher Cucco
  • Mechanical: Gravenhurst Plumbing and Heating