Alternatives to Drain Water Heat Recovery

Published on November 28, 2018

For a home to pass Ontario Building Code, it needs to have a working drain water heat recovery system. This is to ensure that Ontario homes are built with energy efficiency in mind and have a system that can effectively recycle the energy used to make hot water.

However, not all homes are capable of having a drain water heat recovery system installed. In homes where the drain exit is high on the foundation wall, there is not enough room to properly mount the pipe vertically - a problem which is sometimes seen in rural basements. To still meet Ontario Building Code, and to make up for the efficiency that is lost from not having a drain water heat recovery system, the home needs to increase energy efficiency through alternate energy saving strategies.

The Path to Alternatives

It is beneficial to look at the efficiency of a home as an interconnected system. If one part of the system changes or a new part is added, the rest of the system is affected and may need to be modified to accommodate. Having a Registered Energy Advisor on hand allows the entire scope of a home’s efficiency to come into play, as they are capable of conducting assessments that evaluate all aspects of energy efficiency within a home.

An Energy Efficient Design Summary, or EEDS, is a necessary assessment for homes that are incompatible with a drain water heat recovery system. It can only be conducted by a Registered Energy Advisor, and its purpose is to ensure that a home still complies with the Ontario Building Code in terms of energy efficiency.

Energy Efficient Design Summary (EEDS)

When a home is incompatible with a drain water heat recovery system and an EEDS of the building is performed, it involves a Registered Energy Advisor modelling the home into a computer program. This shows the annual energy usage of alternative changes that may be used in place of a drain water heat recovery system.

A number of different options may be available, each with different benefits and costs, and each having a different overall impact on the home’s interconnected system of energy efficiency.  A Registered Energy Advisor is capable of explaining how each modification will affect overall annual efficiency, as well as what options are the most cost effective to employ.

Possible Alternatives

A home that is incompatible with a drain water heat recovery system is just like any other home that is trying to improve its level of energy efficiency. As air leaks and poor insulation can be the most detrimental factor in preventing a home from being efficient, it is beneficial to have a Registered Energy Advisor conduct an EEDS as well as an Air Tightness Test. These tests locate all possible areas of air leakage, in addition to arming the advisor with information that speaks directly to the efficiency levels of the home. This allows the advisor to present the homeowner with an informed list of options to improve energy efficiency, as well as what supplemental modifications may or may not be needed in order to support a significant change to the home’s overall efficiency levels and strategy.  

In most homes, the level of insulation in the attic can be improved with little cost, making it the best investment a homeowner can make towards improving their home’s efficiency. Similarly, improving the level of air sealing is also a common and cost-effective solution, as reducing the amount of interior air that escapes lowers the demand that is put on HVAC systems to maintain desired temperature levels. This is effective in reducing energy consumption and also greatly improves home comfort.