Shared Heat Networks, Explained

How does district heating work?

A central plant heats water. Pumps push it through buried, insulated supply pipes to buildings, where a heat exchanger or coil takes the heat and the cooler water returns to the plant in a second pipe. Inside each building the heat feeds radiators, floor loops or air coils, so occupants usually see only a thermostat.

Canadian systems exist at several scales, from campuses and hospital complexes to downtown cores and new neighbourhoods. This guide describes the principles, not a ranking of particular networks.

Why does density matter?

Piping is the big cost, and it is paid per metre. Many buildings along a short pipe run share the cost and the heat loss of that pipe. Few buildings spread over a long run do not. Planners often talk about heat demand per metre of pipe, which is why apartment blocks, mixed-use streets and campuses suit district heating better than scattered acreages.

Low-density suburbs can still work, if the loop is cheap and well insulated and the temperature stays low. The trade-offs are weighed in district energy versus individual heating.

What can supply the heat?

The plant can burn natural gas or biomass, capture waste heat from industry or buildings, run large heat pumps, or collect solar heat. Because the source sits in one place, it can be changed later without touching the buildings. That flexibility is a core argument for district systems in a cold climate where fuel choices will keep shifting.

Storage helps too. A tank or a seasonal store smooths the gap between when heat is made and when it is needed. See seasonal thermal energy storage for the long-term version.

What does temperature have to do with it?

Older networks send water at high temperatures, often well above 80 C. Newer designs use lower temperatures, which cut pipe losses and let heat pumps and solar collectors work efficiently. Buildings need larger heat-exchange surfaces to make up for gentler water, such as low-temperature hydronic systems.

What did Drake Landing show?

Drake Landing Solar Community in Okotoks, Alberta, ran a small, low-temperature district loop for 52 homes, with water typically at 40 to 50 C. Four home-run loops left the Energy Centre, and each house had an air handler instead of a furnace. Details are on the district heating page and the air handler page. Monitoring reported a 97% solar share by 2012 and 100% in the 2015-16 heating season. The system was later wound down, with decommissioning beginning in 2024, and the homes mostly switched to natural-gas furnaces.

What do residents see and pay?

For a resident, the system is mostly invisible. There is a thermostat, a heat meter or a flat charge, and a bill from the system owner. Heat meters measure the energy that passes through the building's heat exchanger, so charges follow use. The details differ by owner, whether a municipality, a utility, a university or a private developer, so it pays to read the service agreement. Questions worth asking cover rate setting, how repairs inside the building are shared, and what happens if the network is sold or closed. For a view of how a shared plant compares with equipment in each house, see district energy versus individual heating.

A short worked example makes the cost logic plain. If a pipe run of 200 m serves 4 buildings, each carries 50 m of pipe. The same run serving 40 buildings gives each just 5 m. Heat loss and trenching costs per building drop by about the same factor, which is why dense areas are favoured.

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