Combi Boiler Only
For an existing Air Handler that is still in suitable condition. We confirm heating capacity, water temperature, pump, controls and piping compatibility.
Contact for Pricing
BEST HOMEHeating & Cooling Ltd.Existing small-duct high-velocity systems
Replace your Combi Boiler or High-Velocity Air Handler.
Already have small round supply outlets in the walls, floors or ceilings? Best Home replaces the equipment used in existing Combi Boiler and Small-Duct High-Velocity heating systems across the GTA.
Equipment replacement & installationContact for Pricing
This service is intended for homes that already have a Combi Boiler, High-Velocity Air Handler or small-duct system.How your existing heating system is connected
1Combi BoilerProduces domestic hot water and heats the closed heating loop
→2Hot-Water Coil + Air HandlerThe coil heats the air and the high-velocity blower moves it
→3Small Round OutletsWarm air travels through small flexible supply tubes into each room
If the system also cools the home, its cooling coil and outdoor A/C may use the same High-Velocity Air Handler.
Replacing the existing heat source
Your Combi Boiler does more than a standard tankless unit.
In this type of system, the Combination Boiler normally supplies domestic hot water for showers and taps while also heating water for the Air Handler’s closed heating loop. The Air Handler depends on that heating-water output to warm the home.
That means a standard tankless water heater is not automatically a like-for-like replacement. The new Combi Boiler must be checked against the home’s heating load, hot-water demand, existing coil, pump, controls, venting and piping before it is selected.
Domestic hot waterHeating water for the Air HandlerExisting piping and venting reviewEquipment compatibility check
What each component does
The Combi makes the heat. The Air Handler moves it.
Understanding those two jobs helps explain why replacement equipment must be matched.
The Combi Boiler heats the loop.
When the thermostat calls, the boiler supplies heated water to the Air Handler. It also supplies domestic hot water through a separate internal path.
The hot-water coil heats the air.
Heating-loop water passes through a coil inside the Air Handler. Household air picks up that heat as it moves across the coil.
The blower feeds the small ducts.
The High-Velocity blower pushes the warmed air through compact supply tubes and out of the small round or slotted outlets.
The closed-loop heating water does not come out of the faucets. Domestic water and heating-loop water remain separate inside a properly designed Combi system.
1High-Static BlowerDesigned to move air through compact supply tubing
→2Small Flexible DuctsOften routed inside walls, floors and ceilings
→3Round or Slotted OutletsSmall outlets deliver conditioned air into each room
Small-Duct High-Velocity Air Handler
It is not the same as a conventional central furnace.
A Small-Duct High-Velocity system uses compact supply tubing and small outlets instead of the larger ducts and registers common in a conventional furnace system. Its Air Handler is designed to move air against the higher pressure created by those smaller ducts.
For heating, the Air Handler uses a hot-water coil supplied by the Combi Boiler. If the home also has air conditioning, a cooling coil and outdoor condenser may use the same blower and small-duct network. When replacing the Air Handler, both the heating and cooling sides must be checked.
High-Velocity Air Handler replacementContact for Pricing
Identify the system already in your home
Central furnace, High-Velocity system or standard tankless?
If you see small round outlets and water lines running to the Air Handler, your replacement belongs on this page.
| Compare | Conventional Central System | Combi + High-Velocity System | Standard Tankless |
|---|---|---|---|
| Heating source | A gas furnace produces the heat | The Combi Boiler heats water for the Air Handler’s hot-water coil | A standard tankless unit is normally for domestic hot water only |
| Air distribution | Conventional larger ducts and rectangular supply registers | Small flexible supply tubes with small round or slotted outlets | Does not distribute space-heating air |
| Main indoor equipment | Furnace, evaporator coil and central blower | Combi Boiler, hydronic coil and High-Velocity Air Handler | Tankless water heater |
| Cooling | Usually paired with a central outdoor A/C unit | May use a cooling coil and compatible outdoor A/C through the same Air Handler | Not part of the cooling system |
| Where to request replacement | Use our Furnace or Air Conditioner pages | Use this page for the Combi, Air Handler or both | Use our Water Heaters page |
| Pricing | Published pricing is available for selected equipment | Contact for Pricing | Published model pricing is available |
Help us identify the correct replacement
Send the existing equipment information first.
You do not need to know the exact model. Start the request and we will tell you which photos are needed.
Combi Boiler label
Model and serial number, if readable.
Full boiler installation
Piping, venting, drain and surrounding space.
Air Handler label
Model, serial number and full equipment view.
Existing cooling equipment
Indoor coil and outdoor A/C information, if connected.
Replacement questions
What can stay, and what needs to change?
Can I replace only the Combi Boiler?
Often, yes—if the existing Air Handler, hot-water coil, circulator and controls are still in suitable condition and compatible with the new boiler. We verify that before quoting a boiler-only replacement.
Can I replace only the High-Velocity Air Handler?
Often, yes—if the existing Combi Boiler can provide the required heating-water temperature and capacity, and the replacement Air Handler can be matched to the existing small-duct and cooling system.
Can a standard tankless water heater replace my Combi Boiler?
Not as an automatic like-for-like replacement. A standard tankless unit normally supplies domestic hot water, while your existing Combi may also be the heat source for the Air Handler. The whole heating sequence must be reviewed first.
Will my existing air conditioner still work after replacement?
It may, but the cooling coil, blower airflow, outdoor unit and controls must all be compatible. We inspect the existing cooling equipment before confirming what can be retained.
Do the small round ducts need to be replaced?
Not necessarily. If the existing tubing, outlets and main plenum are in good condition and suitable for the replacement equipment, they may remain. Airflow and system condition still need to be checked.
Already have this system?
Replace the equipment without guessing at compatibility.
Tell us whether you need the Combi Boiler, High-Velocity Air Handler or both replaced. We will review the existing setup before confirming equipment and price.