Expert Boiler Installation, Repair & Maintenance
Keep your home warm and efficient with our top-rated boiler services. Serving the community with reliable heating solutions.
24/7 Service
Emergency repairs available
Certified Techs
Licensed & insured
30-Day Warranty
100% Satisfaction Guarantee
Understanding Your Heating System
Knowing the difference between boiler types helps you make the right choice for your home's needs.
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What is a Combi Boiler?
A combination (combi) boiler provides both home heating and on-demand hot water from a single compact, wall-hung unit. It heats water instantly from your home's main water line when you turn on a tap, so you don't need a separate hot water tank, freeing up space in your basement or utility room.
- Highly efficient and compact
- Instant hot water
- Ideal for smaller homes or apartments
What is a Heat Only Boiler?
A heat-only boiler is dedicated to space heating through radiators, baseboards, in-floor radiant heat or a hydronic air handler. For hot water, it is usually paired with a separate indirect hot water tank that the boiler heats. It's a great fit for larger GTA homes where several showers and fixtures are used at the same time.
- Perfect for larger homes with multiple bathrooms
- Compatible with older radiator systems
- Requires space for a separate indirect hot water tank
Find the Right Boiler Solution for Your Needs
We offer specialized solutions tailored to your specific home setup and heating requirements.
Combi Boilers for Condos & Townhouses
Space-saving solutions perfect for properties without room for water tanks. Maximum efficiency in a minimal footprint.
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Get Rid of Your Tank Water Heater
Upgrade to a combi boiler to eliminate bulky, inefficient tank water heaters and enjoy endless hot water on demand.
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Break Free From Your Rental Boiler
Stop paying endless monthly fees. We help you replace your rented unit with a high-efficiency boiler you actually own, saving you thousands long-term.
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High-Efficiency Floor Model Upgrades
Replacing older floor-standing models with wall-hung or modern compact units to reclaim floor space and boost efficiency.
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Boilers for In-Floor Heating
Specialized boiler systems designed to operate at lower temperatures for optimal radiant in-floor heating performance.
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Boilers for Radiators & Air Handlers
High-temperature systems perfectly matched for traditional cast iron radiators, baseboards, or hydronic air handlers.
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Top Brands We Install & Service
We partner with industry-leading manufacturers to provide you with the most reliable and efficient heating systems.
Rinnai Condensing Boilers
Rinnai condensing boilers deliver efficient, reliable home heating in an ultra-compact, wall-hung design. Choose an i-Series heat-only boiler for radiators, in-floor heating or air handlers, or a Rinnai combi boiler for heating plus endless on-demand hot water.
Rinnai Heat Only Boilers
| MODEL | HEATING CAPACITY (BTU/H) | MAX HOME SIZE* | NOTES |
|---|---|---|---|
|
I-Series I090S | 90,000 | Up to 2,500 sq. ft. | Medium homes, Air Handlers, Baseboard or Rads |
|
I-Series IP120S | 120,000 | Up to 3,000 sq. ft. | Larger homes, Radiant Heat |
|
I-Series I150S | 150,000 | Up to 3,500+ sq. ft. | Big houses / light commercial |
|
I-Series IP200S | 200,000 | Up to 4,500 sq. ft. | Large House, Snow Melting, Commercial Multi-Unit apartment |
Rinnai Combi Boilers
| MODEL | HEATING CAPACITY (BTU/H) | DHW CAPACITY (BTU/H) | MAX HOME SIZE* | NOTES |
|---|---|---|---|---|
| IP06160C | 60,000 | 160,000 | Up to 1500 sq ft | ⭐ Economy Space Saver |
| IP090160C | 90,000 | 160,000 | Up to 2200 sq ft | ⭐ 96% Efficient |
| IP090199C | 90,000 | 199,000 | Up to 2400 sq ft | ⭐⭐⭐ Most Popular Air Handler |
| IP120199C | 120,000 | 199,000 | Up to 3000 sq ft | ⭐⭐⭐ High Output Air Handler, Radiant Heat |
| IP150199C | 150,000 | 199,000 | 3000+ sq ft | 🚀 Max Performance |
Navien Condensing Boilers
Navien's high-efficiency condensing boilers are industry leaders in advanced technology. With dual stainless steel heat exchangers, they offer unparalleled durability and significant energy savings.
Navien Combi Boilers
| NAVIEN MODEL | HEATING CAPACITY (BTU/H) | DHW CAPACITY (BTU/H) | IDEAL HOME SIZE / APPLICATION |
|---|---|---|---|
| NCB-190/060H | 60,000 | 160,000 | Condos & small homes up to 1,500 sq ft |
| NCB-190/080H | 80,000 | 160,000 | Homes up to 2,000 sq ft |
| NCB-240/110H | 110,000 | 199,000 | Homes up to 2,800 sq ft |
| NCB-240/130H | 130,000 | 199,000 | Homes up to 3,500 sq ft |
| NCB-250/150H | 150,000 | 199,000 | Large homes up to 4,500 sq ft |
| NFC-250/175H | 13,300–175,000 | 13,300–210,000 | Must be determined by heat-loss calculation |
| NFC-250/200H | 199,900 | 210,000 | For applications requiring up to 199,900 BTU/h heating input |
Navien Heat Only Boilers
| MODEL | MAXIMUM INPUT (BTU/H) | HEATING CAPACITY (BTU/H) | GENERAL APPLICATION |
|---|---|---|---|
| NHB-55H | 55,000 | 51,000 | Lower heating-load hydronic systems |
| NHB-80H | 80,000 | 74,000 | Moderate heating-load hydronic systems |
| NHB-110H | 110,000 | 102,000 | Higher heating-load hydronic systems |
| NHB-150H | 150,000 | 138,000 | Higher-capacity hydronic heating systems |
| NFB-175H | 175,000 | not listed | Large residential buildings, multi-unit properties, or light-commercial spaces up to ~5,000 sq ft |
| NFB-200H | 199,000 | not listed | Large residential, multi-unit, and light-commercial properties up to ~6,000 sq ft |
Viessmann Precision Engineering
German-engineered Viessmann boilers are synonymous with superior quality, longevity, and intelligent design. Ideal for comprehensive heating systems requiring exact temperature control.
Essential Boiler Upgrades & Add-ons
Maximize the efficiency, lifespan, and safety of your new heating system with these highly recommended additions.
Essential Add-ons
Isolation Valves
For easy maintenance without draining the full system.
Expansion Tank
Sized correctly for your boiler’s water volume and pressure
Auto Feeder & Pressure Regulator
Maintains consistent pressure with backflow prevention
System Circulator Pump
New high-efficiency pump with flange connections
Outdoor Sensor
Adjusts boiler temperature based on outdoor weather.
Hydronic Piping
Oxygen-barrier PEX, copper, or steel depending on your system layout.
Optional Add-ons
Air Eliminator
Removes trapped air and oxygen bubbles to prevent corrosion.
Dirt & Magnetic Separator
Captures rust and metal particles in older radiator systems.
Low-Water Cut-Off
Protects the unit from overheating when water levels drop.
Zone Controller
Manages multiple heating zones for customized comfort.
Manifold with Zone Valves
Enables individual zone control and easy maintenance.
Low-Loss Header
Increases efficiency and flow balance for larger multi-zone systems.
Why Choose 4Most Energy?
At 4Most Energy, we understand that a reliable boiler is the heart of a comfortable home. Our certified technicians specialize in the installation, repair, and maintenance of all major boiler brands.
We pride ourselves on transparent pricing, meticulous workmanship, and helping homeowners find the most energy-efficient solutions to lower their utility bills and reduce their carbon footprint.
30-Day Satisfaction Warranty
Your peace of mind is our priority. If you're not completely satisfied with our service, we'll make it right.
Our Recent Installations
Take a look at some of the clean, high-quality boiler setups we've recently completed for homeowners.
Service Area
Greater Toronto Area (GTA) and surrounding regions
Toronto, Markham, Richmond Hill, Vaughan, Aurora, Newmarket, Scarborough, Brampton, and Mississauga.
Extended Service Area: Stouffville, Oshawa, Barrie, Orangeville, Hamilton, St. Catharines, Guelph, Kitchener.
Request a Free Boiler Estimate
Fill out the form below and one of our heating specialists will contact you shortly to discuss your needs.