Floor Boiler Replacement · GTA
Trade Your Old Floor Boiler for a Compact High-Efficiency Upgrade
Replace that bulky, old floor-standing boiler with a modern wall-hung condensing unit. Reclaim your floor space, cut wasted gas and get quieter, steadier heat.
Wall
Hung, not floor-standing
96%
Efficient Rinnai models
20+
Years in the GTA
Time to upgrade?
Signs Your Floor Boiler Is Holding You Back
Many GTA homes still run on floor-standing boilers installed decades ago. They keep working — but they waste gas, take up space and get harder to repair every year.
- Your boiler is 20 years old or more
- Gas bills keep creeping up
- Some rooms are cold while others overheat
- Banging, rumbling or noisy operation
- Rust, leaks or water around the base
- Frequent repairs and hard-to-find parts
Old vs. new
What Changes When You Upgrade
Footprint
OLD: A large cast-iron unit sitting on the floor.
NEW: A compact unit mounted on the wall.
Efficiency
OLD: Older non-condensing boilers send much of their heat up the chimney.
NEW: Condensing technology captures extra heat from the exhaust.
Venting
OLD: Usually vented through the chimney.
NEW: Usually vented through a side wall with PVC pipe.
Comfort
OLD: Runs at one fixed temperature all winter.
NEW: An outdoor sensor adjusts the water temperature to the weather.
Heat-only boilers
Rinnai & Navien Boilers: Sized to Your Home
Wall-hung, heat-only condensing boilers for radiators, baseboards, in-floor heat or air handlers. Final sizing is based on your home, not the size of your old boiler.
Medium homes
Rinnai I090S
BTU/h heating
- Up to 2,500 sq ft
- Air handlers, baseboard or rads
Most versatile
Rinnai IP120S
BTU/h heating
- Up to 3,000 sq ft
- Larger homes, radiant heat
Big houses
Rinnai I150S
BTU/h heating
- Up to 3,500+ sq ft
- Big houses / light commercial
Large & multi-unit
Rinnai IP200S
BTU/h heating
- Up to 4,500 sq ft
- Snow melting, multi-unit
Small to medium homes
Navien NHB-H Series
BTU/h input, four sizes
- 95% AFUE condensing
- Built-in zoning controls
Large homes
Navien NFB-175H
BTU/h heating
- Heavy-duty performance for large homes
- 15-year heat exchanger warranty
Maximum output
Navien NFB-200H
BTU/h heating
- 95% AFUE condensing
- 15-year heat exchanger warranty
Also have a hot water tank?
A combi boiler can replace your floor boiler and your tank with one wall-hung unit.
Done right
Built for Older Hydronic Systems
Older radiator systems often carry rust and sludge. We match the right components to protect your new boiler.
Dirt & Magnetic Separator
Captures rust and metal particles in older radiator systems.
Outdoor Sensor
Adjusts boiler temperature based on outdoor weather.
System Circulator Pump
New high-efficiency pump with flange connections.
Expansion Tank
Sized correctly for your boiler’s water volume and pressure.
Auto Feeder & Regulator
Maintains consistent pressure with backflow prevention.
Air Eliminator
Removes trapped air and oxygen bubbles to prevent corrosion.
Isolation Valves
For easy maintenance without draining the full system.
Zone Controls
Manage multiple heating zones for customized comfort.
How the upgrade works
From Floor Boiler to Wall-Hung in 4 Steps
1. Home assessment
We look at your boiler, radiators, piping, venting and chimney.
2. Right-sized recommendation
We size the new boiler to your home’s heat loss and hot-water needs.
3. Clean installation
Our TSSA-licensed team removes the old floor unit and installs the new boiler.
4. Warranty & support
One year of free labour from 4Most, plus manufacturer coverage.
Floor Boiler Upgrade Questions
Straight answers about replacing an old floor-standing boiler.
Will a wall-hung boiler work with my old cast iron radiators?
Yes. Modern condensing boilers work with radiators, baseboards, in-floor heat and air handlers. In older systems we often add a dirt and magnetic separator to capture rust and sludge, and an outdoor sensor so the boiler adjusts its temperature to the weather.
What happens to my chimney?
Most high-efficiency boilers vent through a side wall with PVC pipe instead of the chimney. During the estimate we check your venting and any other appliance that still uses the chimney, such as a water heater.
Should I choose a heat-only or a combi boiler?
If you also have a hot water tank and one to three bathrooms, a combi boiler can replace both. Larger homes with several bathrooms in use at once are often better served by a heat-only boiler with an indirect hot water tank.
I rent my boiler from Reliance or Enercare. Can I still upgrade?
Yes. If your rental contract is up, or the rented unit has stopped working and you don't want to sign a new contract, we coordinate the return and the contract termination, then install a combi boiler you own. It's a good replacement for Baxi, Flowmax, and older Rinnai and Navien models.
What maintenance does a boiler need?
Very little. These units are solid and usually last 15 to 20 years, and they hardly need major service before the 15-year mark. A yearly clean and tune-up is ideal, and our maintenance plans start from $12.99. Without a plan, have a certified technician check the unit at least every 5 years.
How does the warranty work?
4Most gives you one year of free labour on any installation issue or repair. Most boiler manufacturers cover parts for 5 years and the heat exchanger, the most expensive part, for 15 years. After the first year, if you need service, you pay for the service call and the repair labour, but not for the part. We also offer extended labour warranties for 5 or 10 years.
Why isn't the installation price on the page?
Every home is different. The price depends on the boiler you choose, how it will be vented and how much piping needs to change, so we quote each home individually.
Request a Free Boiler Estimate
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