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A Manufacturer’s Guide to High Performance CSA P.9 Tested Combination Systems

Executive Summary:

This CanmetENERGY report provides guidance to manufacturers of condensing on-demand water heaters. Inside, readers will find strategies for designing high performance combination systems for space- and water heating, and information about certifying performance with CSA P.9 testing.

When properly designed, on-demand condensing water heater based combination systems can be very energy efficient. One of their biggest advantages is that they can vary the supply water heating temperature in space heating mode to improve overall combination system performance by 10% or more.  By distinguishing between heating and hot water loads, carefully-engineered packaged systems can condense almost all the time.

This report helps manufacturers and design engineers:

  1. understand one approach to developing a high performance combination system,
  2. identify and address risks in the development process and use resources most effectively, and
  3. develop specifications for potential component suppliers. 

The report also explains how the CSA P.9 test standard emphasizes different aspects of product performance, and which ones are most important to achieving high performance ratings.

The guide discusses component requirements, suggests control approaches, and highlights some issues that that manufacturers should anticipate when in developing a cost effective and efficient combo using a condensing on demand water heater.

The guide is available at no cost; please contact: for further information.


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