Most industrial facilities have a heat loss problem they can’t see. Heat is leaving the system continuously through walls, pipes, openings, and idling equipment. Losing heat means losing energy, causing the machines in your process to work harder, raising the ambient temperature, decreasing efficiency and even shortening equipment life span. The solution starts by understanding where heat escapes your system.

The U.S. Department of Energy identifies the major sources of energy loss in fuel-based systems. In this article, we’ll cover each source and explain the most efficient solution to help you solve this problem.

1. Furnace and Heater Walls

Hot surfaces like furnaces, dryers, and heat exchangers continuously lose energy through both radiation and convection. This is sometimes called wall loss or surface loss. Unfortunately, it is present any time the equipment is operating, even when it’s holding temperature between runs.

On it’s own this is not the worst heat loss issue, but when poor or degraded insulation on furnace walls goes unreplaced heat loss increases dramatically.

Per the US Department of Energy, poor insulation conditions are a key source of energy loss and often overlooked during routine maintenance reviews. Furnace walls, connected piping or ductwork are the most common areas for heat loss in this first category.

Fortunately the solution for this category is fairly simple; Regularly replacing insulation with insulation solutions, like those found on shop.unitherm.com, is a simple, cost effective fix.

2. Openings, Doors, and Seals

Every time a furnace door opens, heat escapes by radiation. Even closed doors with gaps and worn seals can allow radiant heat to escape. Radiation heat loss from openings is a specific category of loss which results from not having proper seals at doors used for material handling.

Checking and maintaining door seals regularly is a low-cost maintenance step that can reduce this loss meaningfully.

3. Flue and Exhaust Gases

For fuel-fired systems, exhaust gases carry a large portion of the heat energy out of the system. Flue gas losses are one of the largest sources of energy loss in fuel-based process heating. The higher the exhaust gas temperature, the more energy is being lost.

This is the category that waste heat recovery systems are designed to address — capturing heat from the exhaust stream and putting it back to work, either as preheated combustion air or for other process uses.

4. Piping and Ductwork Without Insulation

Hot piping, ductwork, and valves that run between the heating source and the process lose heat at every uninsulated foot. This is especially relevant in facilities where heated fluids, gases, or steam travel significant distances. Each uninsulated surface is a continuous energy drain.

UniTherm’s IsoCovers are removable insulation covers designed for pipes, valves, and flanges. They’re an effective, convenient, and low-cost way to address heat loss on piping components — and because they’re removable, they don’t interfere with maintenance access. Learn more at unitherm.com/pipe-and-components.

5. Idle and Low-Capacity Operation

Process heating systems have both fixed and variable losses. Variable losses depend on how much material is being heated. Fixed losses occur as long as the unit is operating, regardless of capacity. When a furnace sits idle between batches or runs at low capacity for extended periods, those fixed losses — wall heat, exhaust gases, radiation — continue accumulating without productive output to offset them.

Scheduling improvements that reduce idle time are one of the enabling technologies the DOE sourcebook identifies for improving overall system efficiency.

Where to Start

Not every facility has the same loss profile, and not every improvement requires capital investment. A walk-through of your system with attention to surface temperatures, insulation condition, and door or seal integrity can reveal opportunities quickly. If pipes, valves, or equipment surfaces are hot to the touch — or hot enough to be uncomfortable to stand near — that heat is money leaving your process.

For our standard removable insulation solutions, visit shop.unitherm.com.

To request a quote for a custom insulation solutions click here.

Source: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

If you work in manufacturing, process heat is your largest energy cost. The worst part is you’re spending even more because of heat waste.

According to the U.S. Department of Energy process heating consumes more energy in U.S. manufacturing than any other single system. The number is striking: more than 7,000 Trillion Btu per year! That’s roughly 61% of all manufacturing on-site energy use. For individual facilities, the energy used for process heating typically accounts for 2% to 15% of total production costs.

Even a modest improvement in how efficiently your system generates, contains, and transfers heat can translate into real savings without changing your process. Let’s take a look at what process heating is, where it goes and how to utilize more of it.

What “Process Heating” Actually Covers

Process heating is broader than most people assume. It includes furnaces, ovens, kilns, dryers, and heaters used across industries from primary metals to plastics to food processing. It covers fuel-based systems, electric-based systems, and steam-based systems. Virtually any operation that requires controlled heat to transform a material falls under this umbrella.

Process heating operations, include forming, curing, drying, fluid heating, heat treating, and metals reheating. Each one has specific efficiency characteristics and specific opportunities for improvement.

Where the Energy Goes

A process heating system does not deliver all of its energy to the product. Heat escapes, whether that’s from furnace walls and openings, or with hot exhaust or flue gases, no can be 100 percent efficient. Despite that, there are still significant benefits to increasing process heat efficiency. By managing process heat, you can extend the life of your machines, increase overall output and reduce downtime.

The goal of any efficiency improvement program is not to eliminate all heat waste, but to reduce those losses and increase the share of energy that actually does useful work.

The Five Categories of Improvement

The DOE groups efficiency opportunities into five categories: heat generation, heat containment, heat transfer, waste heat recovery, and enabling technologies. These categories overlap in practical application, but they provide a useful framework for identifying where to start. Here’s a brief summary of each category:

• Heat Generation: the process of producing heat energy. It happens when energy from sources like fuel, electricity, friction, or chemical reactions is converted into heat.
• Heat Containment: the process of keeping heat within a specific area or system to reduce heat loss and maintain temperature. It is often achieved using insulation, barriers, or enclosed spaces.
• Heat Transfer: the movement of heat energy from one object or area to another, moving from a hotter place to a cooler place.
• Waste Heat Recovery: the process of capturing heat that would otherwise be lost from a system or process and reusing it for another purpose, improving energy efficiency and reducing energy costs.
• Enabling Technologies: tools, equipment, and systems that help industrial processes use heat more effectively, reducing energy consumption, costs, and emissions while maintaining or improving performance.

Heat containment is the area where most facilities can make meaningful gains quickly and at relatively low cost. Poorly maintained or missing insulation allows heat to escape continuously, adding to energy costs every hour the system runs. Here’s a list of where insulation should be in your facility:

Process Heat Efficiency Opportunities:

• Steam and condensate piping
• Valves, flanges, and fittings
• Boilers and boiler doors
• Heat exchangers
• Process tanks and vessels
• Ovens, furnaces, and kilns
• Ductwork carrying heated air or gases
• Hot water piping and storage tanks
• Turbines and associated equipment
• Any surface operating at elevated temperatures where personnel protection or energy conservation is required

UniTherm Insulation Systems designs removable and reusable insulation jackets, blankets, and covers for industrial equipment — purpose-built for the heat containment challenge. Products like UniVest® for plastics processing equipment and IsoCovers® for pipes and valves help facilities reduce surface heat loss without requiring permanent modifications.

If you’re not sure where your facility stands, simply take stock of which surfaces and components are uninsulated or under-insulated. You may be surprised what you find.

Click here to browse our standard insulation solutions

Click here to recieve a quote for a custom insulation project.

Further reading: U.S. DOE, Improving Process Heating System Performance: A Sourcebook for Industry (Third Edition), 2015.

Ask any maintenance team that has dealt with conventional pipe lagging — fiberglass, calcium silicate, foam glass — and you’ll hear the same complaints. It’s wet. It falls apart. Every time you need access to a valve or flange, you’re cutting it away and starting over. The insulation budget ends up being a recurring expense rather than a one-time installation.

Removable insulation covers offer a fundamentally different approach — and for valves, flanges, expansion joints, and other components that require periodic access, they make more operational and economic sense than any conventional alternative.

The Real Cost of Conventional Valve Insulation

Valves require annual maintenance, and annual maintenance requires removing traditional lagging. Besides the obvious cost of labor and disposal, other hidden costs inflate maintenance projects and increase project duration.

What you are risking with traditional lagging:

• Labor cost to remove and dispose of the old insulation
• Material cost to install new insulation after access
• Downtime to complete the work and preform reinstallation.
• Coverage gaps, moisture infiltration, and inadequate vapor barriers.

Across a large facility with hundreds of insulated valves and flanges, this adds up to a significant and largely avoidable maintenance burden.

How do ISOCOVERS Work?

UniTherm’s ISOCOVERS, a line of removable insulation jackets designed specifically for valves, flanges, strainers, steam traps, expansion joints, and other piping components solve the need for thermal insulation with the practical reality of meeting access requirements.

Covers come in standard sizes or custom fitted to your application. Closures use heavy-duty fastening systems — typically lacing wire or hook-and-loop — that allow removal and reinstallation in minutes without tools. Unlike lagging, ISOCOVERS maintain their shape even after repeated maintainence cycles, eliminating the need for replacement materials.

UniTherm selects it’s materials for your temperature range and environment: high-temperature wool or ceramic fiber for steam and high-temperature process applications, fiberglass or mineral wool for standard service, and specialized materials for cryogenic or corrosive environments.

Energy Performance: What to Expect

A bare valve in a steam system is a meaningful energy loss point. The surface area of a flanged valve can be many times that of the adjacent pipe. Not to mention, valves and fittings are often completely uninsulated precisely because of the access concern. ISOCOVERS eliminate that tradeoff.

Energy studies on steam systems with significant uninsulated valvework consistently show annual savings that justify cover costs many times over. For high-pressure steam system, retaining BTUs is crucial. BTUs lost to radial heat add up to massive costs across a system with dozens of uninsulated components.

When to Specify Removable Covers

• Any valve, flange, or fitting that requires periodic access — which is essentially all of them
• Steam systems with significant uninsulated valvework
• High-temperature process piping where personnel protection from surface temperatures is a concern
• Systems in environmentally sensitive locations where failed lagging creates housekeeping problems
• New construction where avoiding the conventional lagging cycle from the start is the most cost-effective approach

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