Combi Boiler Water Heaters & Space Heating

One appliance unites high efficiency space heating and hot water

As a leading provider of water heating solutions for over 70 years, State and its tradition of innovation continue to the present day. State offers dependable solutions for water heating needs, including energy-efficient options like combination boiler water heaters that simultaneously provide space heating and domestic hot water supply.

Benefits of Combi Boilers

  • A father carrying a small child while mother prepares food in a kitchen.

    Water & Space Heating Combined

    By uniting two needs in one appliance, combi boilers can serve as both a traditional water heater and space heater in your home. With a high efficiency 95% AFUE rating, these units save space, boast powerful performance and reduce operating costs.

  • A grandmother helping two small children, sitting together on the bathroom counter, brushing their teeth.

    Dependable Hot Water Supply

    The ProLine® XE Combi Boiler offers industry-leading on-demand hot water for your everyday needs through a highly efficient design.

  • A father lieing down on a rug holding a toddler up in the air.

    Powerful Space Heating Performance

    Combi boilers also provide reliable heat for your home. The ProLine® XE Combi Boiler offers powerful space heating performance - up to 74% more heating capacity than comparable units.

  • A woman putting on makeup in the bathroom mirror while her son brushes his teeth beside her.

    Space Savings

    In addition to installing easily and requiring little maintenance, combi boilers fit your everyday needs by fitting into small spaces with a wall-hung design.

  • A dad helps his daughter wash a mug while sitting on the kitchen counter beside the sink.

    Cost Savings

    Highly efficient and environmentally friendly, State combi boilers have a 95% AFUE (Annual Fuel Utilization Efficiency) and are ENERGY STAR® Certified, which can help reduce your energy bills.

  • A young family of four having breakfast together at a table.

    Easy To Install

    State combi boilers install easily with direct venting options up to 100 feet, which gives flexibility on where to install.

A Closer Look

An electric tankless water heater.

What is a Combination Boiler?

A combination, or combi, boiler offers high efficiency space heating and domestic hot water (DHW) while boasting a small footprint. These units install easily and require little maintenance. The water heating process begins with a hot water tap being opened, which causes water to flow through the heat exchanger. Heated boiler water from the fire tube heat exchanger transfers heat to the domestic water to raise it to the desired temperature. A diverter valve moves the heated boiler water to an external space heating loop when space heating is needed.

Combi boilers merge space and water heating into one appliance, providing a space-saving and highly efficient choice to fit your everyday needs. State's industry-leading ProLine® XE Combi Boilers are easy to install and operate, offering hot water delivery and up to 74% more space heating capacity than comparable combination boilers to make sure that daily life in your home is comfortable.

Although combi and traditional boilers can both heat your home and your water, there are key differences between the two.

Designed intentionally for space heating, traditional boilers use hot water circulated through radiators or a hydronic heating system to increase the temperature of the air. A traditional boiler's water can also be used for domestic water heating when paired with a separate indirect water heater. While some traditional boilers are compatible with potable water, others need additional water treatment.

Combi boilers, on the other hand, accomplish both space and water heating with a single appliance very efficiently. Similar to a tankless water heater, a combi boiler provides continuous hot water on-demand and can switch between water and space heating with ease and dependability to ensure your comfort.

Because they are very efficient for both of their uses, space and water heating, using a combination boiler may lead to reduced home energy costs.

Yes! With a 95% AFUE rating, combi boilers are ENERGY STAR® Certified.

State's combi boiler units enable you to have two high efficiency appliances combined as one to provide both space and water heating. With a modulating combustion system with 10:1 turndown, the ProLine® XE Combi Boiler also works hard to ensure high efficiency operation even when heating demands aren't as high.

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