Condensing economizers for hot water boilers.

Want to make your boiler system more efficient with a quick payback?

We are all pushing for increased efficiencies especially in low emission applications. The following guide will help identify economizer opportunities on steam boilers and hydronic boilers.

Add a Standard Economizer to improve your systems efficiency:

Determining if a boiler is a good candidate for an economizer is not difficult. First, establish the source of the exhaust gas, then you’ll need to find the boiler capacity. Exhaust gas inlet temperature is the next variable needed and is usually available via thermometers or plant instrumentation. An important consideration for boilers in California is the type of burner. The single most important variable for sizing an economizer is the maximum allowable flue gas backpressure measured in inches water column. Excessive backpressure will impact the operation of the burner and could skew the results of an economizer calculation. If you have the necessary information that’s great, if not contact us and we can work through the process with you.

Economizer Selector

A very popular option for steam boiler installations with a high amount of cold water is the Two-Stage economizer. This is simply the use of two separate heat exchangers in a common casing; most commonly the First Stage serves to heat boiler feedwater and the Second Stage heats the cold process water. This picture shows a typical Two-Stage economizer on top of a Hurst firetube boiler. This arrangement is called a stacked economizer. For applications where the level of condensing would be expected to be extreme we use a side-by-side arrangement. Units such at these can increase the efficiency of a steam boiler by well over 10% and can be installed in a matter of days.

Add a HeatSponge Sidekick to your existing hot water application:

Perhaps the most ignored opportunities are the potential for heat recovery of hot water systems. We have an answer to this problem - we can install a HeatSponge Sidekick for you. The Sidekick is a revolutionary design that enables heat recovery for extremely high water flow rate applications. The Sidekick’s ability to handle high water flow rates makes it ideal for condensing applications.

With the HeatSponge Sidekick we are able to retrofit conventional efficiency hot water boilers to condensing efficiency without the need to demolish the existing boiler and install a new condensing boiler. Sidekicks can improve the efficiency of a boiler anywhere from 3% to 15%.

For retrofit of existing commercial hot water boilers HeatSponge has developed Efficiency-Match software. This program allows a Sidekick to be designed for a conventional boiler that will match the efficiency a competitive condensing boiler.

Sidekicks are not only for retrofit. For applications that demand large amounts of hot water a larger, conventional boiler with a Sidekick is often far less expensive than multiple condensing boilers.

HeatSponge Sidekick Selector

Standard Economizers for Boiler Heat Recovery:

  • Steam boiler economizers
  • Steam boiler economizers ranging from 25 HP to over 150,000 pph boiler capacity
  • Fully repairable design for both conventional and condensing applications
  • Wide variety of metallurgies allow for flexible application
  • Most modern design available to industry
  • Typical efficiency improvements of 3% to 10%

Hot water boiler economizers

  • Typical efficiency improvements of 3% to 20%
  • Significantly better returns than most condensing boilers

Two-Stage Economizers
Steam Boiler Economizers

  • Designed to provide the maximum efficiency gain on steam boilers
  • Utilizes two separate economizers in a common casing to maximum multiple heat sinks
  • 1st Stage for preheating boiler feedwater
  • 2nd Stage for preheating condensate return, make-up water, or other
  • Two stage economizers can realize efficiency gains of 6% to 10% or greater depending on the heat sink

HeatSponge Sidekick Economizers

  • Condensing economizers for hot water boilers
  • New or retrofit installations
  • Stainless steel construction
  • Customized to each application
  • Eliminates the need to demolish existing conventional boilers and retrofit new condensing
  • boilers to achieve same outcome

Retrofit HeatSponge Sidekick

  • Substantially less expensive than condensing boilers
  • Designed for the greater water flow rates associated with water boilers when compared to steam boilers
  • Allows owners to use rugged, proven, and easy to maintain conventional boiler, burner, and control technology
  • Installation can be quickly accomplished in a few days
  • Allows for oil standby

Contact California Boiler today at 800-775-2645 and get a quote that will ensure your boiler system is operating at maximum efficiency. You may also be available for energy saving rebates as high as 50% of the equipment cost!

Get Quote
boiler service

Quote Request

Our complete line of boiler room equipment includes a wide range of boilers, burners, hot water heaters, feedwater systems, blowdown systems, fuel efficient equipment, control systems, oil heaters and stack systems.

Quote Request


HeatSponge provides both condensing and feedwater economizers and heat recovery applications for commercial and industrial applications to gain efficiency on steam, hot water, hot oil and waste heat units.

  • Two-stage economizers
  • Stainless steel economizers
  • Boiler feedwater economizers
  • Capacities of 50 HP - 1,500 HP
  • Economizers for hotwater boilers