Custom Hot Water Coils.

Custom hot water coils for commercial hydronic heating, replacement, and retrofit requests. Start with measurements of the existing coil or submit an existing drawing through the separate drawings pathway in Coil Brief.

Start a Coil Brief

2–3 minutes with measurements ready.

Front-facing illustrative hot water heating coil with aluminum fins, horizontal copper tubes, galvanized casing, and two water connections on the left.
Hot water coil · Illustrative construction

What does a hot water coil do?

A hot water coil transfers heat from circulating hot water into the air. Water flows through the tubes while air passes between the fins, picking up heat before continuing through the ventilation system. These hydronic coils can provide space heating, preheating, or reheat, depending on the application.

Headers distribute and collect the circulating fluid, while the fins increase the surface area available for heat transfer. A hot water coil uses heated liquid rather than condensing steam or refrigerant. The illustration shows one possible construction. Connection arrangements can vary to suit the installation.

Coil selection

What matters when selecting a hot water coil?

The right coil depends on the heating requirement, airflow, available space, and operating conditions—not building size alone.

What to considerWhy it matters
Heating requirementHeating load and the air temperature needed
Airflow and pressure dropAirflow, fan capability, rows, and fin spacing
Water conditionsWater temperatures, flow, and glycol concentration
Materials and environmentFluid compatibility and environmental exposure
Fit and installation accessDimensions, connections, and removal space

Replacing an existing coil? Start with its measurements or drawing.

Operating data is not required to begin a measurement-based replacement request.

Materials and construction

Explore materials for your hot water coil.

Front-facing hot water coil showing aluminum fins, horizontal copper tubes, galvanized casing, and left-side water connections.
FinsTubesCasing

Relative upfront cost: $ lower · $$ moderate · $$$ higher

Fin materials

  • Illustrative aluminum fin sample showing thin parallel sheets.

    Aluminum

    Relative upfront cost: 1 of 3.

  • Illustrative copper fin sample showing thin parallel sheets.

    Copper

    Relative upfront cost: 2 of 3.

  • Illustrative stainless steel fin sample showing thin parallel sheets.

    Stainless steel

    Relative upfront cost: 3 of 3.

Tube materials

  • Illustrative copper tube sample showing the hollow passage and tube wall.

    Copper

    Relative upfront cost: 1 of 3.

  • Illustrative stainless steel tube sample showing the hollow passage and tube wall.

    Stainless steel

    Relative upfront cost: 2 of 3.

  • Illustrative copper nickel tube sample showing the hollow passage and tube wall.

    Copper nickel

    Relative upfront cost: 3 of 3.

Relative material cost. Final pricing depends on coil specifications.

Illustrative galvanized steel casing corner showing its folded edges.

Casing

The formed frame supports and protects the coil. Galvanized steel and stainless steel casing options are reviewed against the application and approved drawing.

Header materials may include copper, copper nickel, or stainless steel. Final materials and construction are confirmed through the approved drawing.

Heat-transfer fluids

These fluids circulate through the coil to carry heat from the heating system into the air.

  • Water

    Hot water circulates through the coil’s tubes and releases heat into the air passing across the fins. The cooler water returns to the heating system to be reheated before circulating again.

  • Ethylene glycol

    Freeze protection

    Ethylene glycol is mixed with water to help protect the circulating fluid from freezing. The heated mixture flows through the coil and transfers heat into the air, supporting heating systems that may experience cold conditions.

  • Propylene glycol

    Freeze protectionLower toxicity

    Propylene glycol can also be mixed with water to carry heat through a heating system while lowering the fluid’s freezing point. Its lower acute toxicity compared with ethylene glycol can make it preferable where potential exposure is a consideration.

The fluid used depends on the system’s design and operating environment.

Start with the coil measurements or drawings you have. Rowform reviews your submission and follows up if additional information is needed.

Replacement and order details

OEM replacements

Discontinued or unknown model? Start with measurements or a drawing.

Independent aftermarket replacements. Rowform is not affiliated with or endorsed by these brands.

Coil protection

Nano Coating, E-Coating, and optional hydrophilic fin treatment.

Production and delivery

Your quote separates manufacturing and transit estimates.

12-month limited warranty

Coverage begins at documented delivery.

Review your drawing before production.

Check the proposed dimensions, connection locations, materials, construction, and any selected coating on the engineering drawing before approving it. Contact Rowform about discrepancies before approval.

Submitting a Coil Brief does not place an order or require payment. Coil Record keeps your project documents and order updates together.

Start a Coil Brief

Frequently asked questions.