Combi boilers
A combi boiler provides both your heating and your domestic hot water from a single wall-mounted unit — no hot water tank at all. That frees up the space a tank occupied, which in a condo or a small house is often the whole appeal.
Installed cost typically $8,000–$14,000.
When a combi works well
Space is genuinely tight — no tank, no cylinder cupboard · One to two bathrooms with modest simultaneous demand · You're replacing an ageing boiler *and* an ageing hot water tank at the same time — doing both in one unit is where the economics work · Your gas supply and mains water pressure are adequate
When it doesn't
Multiple simultaneous showers. A combi heats on demand at a fixed flow rate. Two showers at once means both run weak. This is the most common regret. Low mains water pressure. A combi's hot water performance depends on it directly. Large homes with several bathrooms. A system boiler with a cylinder handles the load better. You want a bath filled quickly. Combis fill slower than a tank system.
What installation involves
Gas supply check — combis need good flow and often a larger line · Mains water pressure and flow test, which decides whether it's viable at all · Removal of the old boiler and tank · New venting · Condensate drain · System flush before connection · Permits and inspection · Commissioning and balancing
