Combi Boiler vs Boiler + Hot Water Tank
Table of Contents
A combi boiler heats your home and makes on-demand hot water in one compact, wall-hung unit. It suits homes with one or two bathrooms and limited space. A boiler with a separate (indirect) hot water tank costs more to install. It handles several showers at once much better, so it suits larger North Shore homes with three or more bathrooms. Installed, a combi boiler typically costs about $9,000 to $15,000 in Metro Vancouver. A boiler with an indirect tank is usually about $12,000 to $20,000.
How each system works
Combi boiler. One unit does two jobs. When a tap opens, it switches from home heating to heating water as it flows through, like a tankless water heater. There is no storage tank. Common models on the North Shore include the Navien NCB, Viessmann Vitodens 100/111 combi and IBC combi units.
Boiler + indirect tank. A heating-only boiler heats the house. A separate insulated tank stores hot water, heated by a coil connected to the boiler. You have a stored supply ready to use, and the boiler refills it quickly.
Boiler + separate water heater. Some older homes have a boiler for heat and a completely separate gas or electric hot water tank. When the boiler is replaced, this is often the moment to decide between a combi and an indirect tank.
Side-by-side comparison
| Combi boiler | Boiler + indirect tank | |
|---|---|---|
| Approximate installed cost (2026) | $9,000 – $15,000 | $12,000 – $20,000 |
| Space needed | Wall-mounted, very small | Boiler plus a tank of about 40–80 gallons |
| Hot water supply | Endless, but limited flow at once | Large stored supply plus fast recovery |
| Two showers at once | Possible on larger models, flow drops | Comfortable |
| Best for | 1–2 bathrooms, condos, townhouses, smaller houses | 3+ bathrooms, soaker tubs, large families |
| Running cost | Very efficient, no standby loss | Very efficient, small standby loss from the tank |
| Maintenance | Yearly service plus regular descaling | Yearly boiler service plus tank check |
Want an exact price for your home?
These are ranges. We give you a free on-site estimate and a fixed written price before any work starts.
Prices are approximate ranges. They include the unit, removal of the old equipment, venting, permit and commissioning. Large piping changes, zone upgrades or chimney work cost extra.
When a combi boiler is the right choice
- You have one or two bathrooms, and rarely run two showers at once
- Space is tight: a condo, townhouse or small mechanical room
- You want to get rid of an old hot water tank and free up floor space
- Your incoming water flow and gas supply are strong enough for the model
When a boiler + tank is better
- Three or more bathrooms, or a large soaker tub
- Several people shower in the morning at the same time
- You already have a good indirect tank that can stay
- Your home has radiant floors or several heating zones that need a larger heating boiler
This is common in larger West Vancouver and British Properties homes. A combi there often leads to complaints about lukewarm showers when two bathrooms run together.
What affects the cost
- Boiler size and brand. Larger outputs and premium brands cost more.
- Venting. High-efficiency boilers vent through plastic pipe. A new vent route, or lining an old chimney used by other appliances, adds cost.
- Near-boiler piping. Older cast-iron systems often need new pumps, valves, an air separator and a low-loss header to work properly with a modern boiler.
- Zones and controls. Adding zone valves, an outdoor reset sensor or smart thermostats adds cost, but improves comfort and efficiency.
- Water quality and system cleaning. Old systems carry sludge that can damage a new boiler. A flush and a filter protect your warranty.
- Permits. Gas and plumbing permits are required. We handle them.
Running costs on the North Shore
Both systems are high-efficiency condensing appliances. Savings come mostly from replacing an old boiler (often 60 to 80% efficient) with a modern one, and from good controls such as an outdoor reset. A combi avoids the small heat loss of a storage tank. A boiler with an indirect tank avoids the short on/off cycles that a combi can make with small hot water draws. For most households, the difference in running cost is small. Choose the system that fits how you use hot water.
Maintenance matters
Both systems need a yearly service. Combi boilers also need their domestic hot water heat exchanger descaled regularly, because heating water on demand leaves mineral deposits. Ignoring this is a common cause of combi breakdowns. See our Viessmann and Navien boiler service guide.
Frequently asked questions
Get the right boiler for your home
Lord Mechanical installs and services combi and heating boilers across North Vancouver and West Vancouver. Our customers give us 4.9 stars from 134 Google reviews. We check your hot water use, piping and venting, and give you a written fixed price for each option.
Boiler Service · Plumber and heating in West Vancouver
