Canada’s winters are extremely cold – but summer temperatures reach 35OC. The country is so large that every type of climate – continental, maritime, alpine, desert and tundra – is represented. Remote communities face challenges ranging from lack of municipal services to social isolation while large Canadian cities face the housing problems of any large cities in industrialised countries. It is no wonder that housing innovation in Canada is practically institutionalised.

This innovation is based upon Canada’s ‘house-as-a-system’ approach and has spawned a high quality and diverse factory-based housing industry that is drawing increasing interest in the UK.

Systems thinking started about 20 years ago when the Canadian government encouraged the industry to increase the energy efficiency of houses. What housing researchers quickly found, however, was that energy efficiency cannot be addressed in isolation.

When insulation levels were increased, airborne moisture accumulated in unexpected places. Reducing air leakage solved the moisture problem but led to indoor air quality problems. These were solved by new ventilation strategies. Researchers had discovered that interaction of all the components in a house determines how the house performs, its durability and the comfort and health of its occupants.

The result was a set of standards – called “Super E” in the UK and known domestically as R-2000.

Canadian off-site housing manufacturers deliver a full range of housing systems from pre-engineered panelised or modular timber components to log homes, post and beam and sandwich panel systems. Adaptable to a wide range of designs, these manufactured systems are pre-cut and partially pre-assembled at the Canadian factory, then packaged and delivered to the building site. This allows high levels of quality assurance, speeds up construction time and lowers costs.

Often the panels are shipped with air leakage barriers and insulation in place. The air barrier not only increases energy performance, but increases the durability of the home by reducing moisture accumulation. An added benefit is acoustic performance. Noise penetration from the outside is significantly reduced through a combination of tightly-sealed insulation and the air barrier. A Super E home with air sealing and multiple-glazed windows is very quiet.

Reduced air leakage allows unprecedented control over the indoor environment. Outside air no longer enters through uncontrolled leaks, but via the mechanical ventilation system. The heart of the ventilation system is a heat recovery ventilator (HRV) – essentially

a heat exchanger with a fan that uses outgoing stale household air to warm incoming fresh air. Having only one source for incoming air allows it to be easily filtered if pollen or outdoor pollution is an issue. The HRV can also be used to keep humidity low enough to prevent mould growth, while keeping it high enough to prevent respiratory irritation.

Healthy housing

As researchers began to see the implications of indoor air quality on health, a whole genre of research began. The term “Healthy Housing” has been trademarked by the Canadian government to describe this research.

Canadian housing research tends to take the form of demonstration projects. Private/public partnerships demonstrate innovative techniques by building houses. The Toronto Healthy House is an example, showcasing the latest Healthy Housing products and techniques. Canada’s national housing agency Canada Mortgage and Housing Corporation (CMHC) helped fund the Toronto Healthy House and other levels of government, electrical utilities, and over 80 private sector sponsors participated.

FlexHousing, similar to the Lifetime Homes approach developed by the Joseph Rowntree Foundation in the UK, is a design concept that allows future changes easily and with a minimum of expense.

Flexible housing

FlexHouses are built with wider doorways and stairs, easily removable partitions, adjustable-height worktops and sinks, and space that can be opened up or subdivided, allowing homeowners to adapt to changing family circumstances.

Many new housing components – beyond the Super E standard – were introduced as a result of the Advanced Houses project. Some components, such as high-performance windows and small-diameter ventilation ducting, are already on the market. Others, such as a high-efficiency combination space heater, water heater and HRV, are in the early stages of market entry.