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Medium

Medium refers to the substance that carries heat through the heating system. Systems are either designed to use either Hot Water or Steam as a medium, and components are usually specific to one or the other.

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DOE Heating Capacity (BTU)

Also referred to as Gross Output, this is the output of a boiler after accounting for combustion efficiency. We recommend sizing hot water boilers based on the DOE Heating Capacity.

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AFUE (%)

AFUE (Annual Fuel Utilization Efficiency) measures the efficiency of combustion equipment over the entire heating season, and is calculated by dividing the amount of energy that is actually heating your home by the total energy contained in the fuel used by the boiler/furnace. Learn More

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To create heat, some form of fuel is required. Fuel Type specifies what the product uses as an input to create heat.

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Vent Type

Products that use combustion (burning) of fuel to create heat also create potentially dangerous gasses that need to be exhausted (AKA "Vented"). Depending on the product, venting can be done via a chimney, through a side wall, or use a second vent to provide fresh air to the appliance.

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DHW Production

DHW (Domestic Hot Water) is potable water for uses other than space heat. Some boilers are able to provide DHW "out of the box", while others can do so with the purchase of optional accessories.

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Triangle Tube Instinct - 142K BTU - 95% AFUE - Hot Water Gas Boiler - Direct Vent

Model: INS155S

Wall Mounted, Condensing Boiler with Modulating Gas Valve. Ships Packaged. Ratings: 155K BTU Gross Input, 142K BTU DOE Capacity, 123K BTU Net IBR Capacity.

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$2,099.00

In-Stock

Free Shipping & Lift Gate

*This product qualifies for Free Shipping anywhere in the contiguous US. Accessories may ship separately. Items over 100lbs shipped via semi-truck, be sure to select "Lift Gate" to lower the product to the ground curbside. Remote area surcharges may apply, see our full shipping policy for more details.

2% Check Discount

Save 2% instantly by using our convenient "e-check" option or by simply mailing us a paper check. Yes, your order will be delayed slightly (5 business days). But, if you can wait, the savings are significant.