Most Alberta homeowners installing a geothermal system focus on the heating and cooling benefit — and rightfully so, given our climate. But there is a third savings stream built into ground source heat pump technology that very few homeowners are aware of before they start researching: the desuperheater.
A desuperheater uses heat that your geothermal system would otherwise discard and puts it toward heating your domestic hot water. In summer, it can effectively provide free hot water. Over a year, it typically covers 40–70% of a household’s hot water needs at little to no additional operating cost. For a family spending $700–$900 per year on gas water heating in Alberta, that is a meaningful addition to the geothermal savings calculation.
The Problem with Conventional Hot Water Heating in Alberta
The typical Alberta home heats water with a natural gas storage tank — an appliance that maintains a tank of water at 60°C around the clock, reheating it as it cools. This standby heat loss costs money even when no hot water is being used. Natural gas water heating in Alberta typically costs between $600 and $950 per year for a family of four, depending on usage and rates.
When a homeowner switches to geothermal for space heating, the gas furnace goes away — but many installations leave the gas water heater in place, meaning the gas line stays connected and the monthly gas bill (including connection fees) continues. A desuperheater addresses this directly by dramatically reducing or eliminating the water heating load from gas.
What Is a Desuperheater?
A desuperheater is a small heat exchanger integrated into your geothermal heat pump that captures excess heat from the refrigerant during the compression cycle — before that heat is sent to the ground loop or the air handler.
To understand why this works, consider what happens inside a heat pump compressor. When refrigerant is compressed, it becomes extremely hot — far hotter than needed for space heating. The refrigerant must be cooled before it can exchange heat efficiently with the ground loop or the air. Conventionally, that excess ‘superheat’ is simply managed within the refrigeration cycle and dissipated. A desuperheater intercepts it first, passing it through a heat exchanger that warms a flow of domestic water on its way to a pre-heat storage tank.
The result: your domestic water is pre-heated using energy that was already being generated by your heat pump for space heating or cooling — not by burning additional gas or drawing extra electricity.
How Much Can You Save on Hot Water in Alberta?
The savings depend on how much your system is running and in what mode, but here are realistic figures for Alberta conditions.
During summer cooling season — which in Alberta runs from roughly May through September — a geothermal system in cooling mode produces heat that must go somewhere. The desuperheater captures this heat for water heating with remarkable efficiency. During peak summer, a desuperheater can cover essentially 100% of domestic hot water needs for a family of four with no additional energy input. This is the most compelling period for desuperheater performance.
During winter heating season — when the system is extracting heat from the ground — the desuperheater still functions but competes slightly with the space heating demand. Performance is typically 30–50% of hot water needs during peak Alberta winter months, still a meaningful contribution.
Across a full Alberta year, most households with a desuperheater see 40–70% of their domestic hot water provided at effectively no extra cost. On a $750 annual gas water heating bill, that represents $300–$525 in savings per year — added on top of the space heating savings from geothermal.
How a Desuperheater Integrates with Your Home’s Hot Water System
A desuperheater does not replace your water heater — it pre-heats incoming water before it enters the main tank. The installation typically involves adding a pre-heat storage tank (50–80 gallons) that sits between your cold water supply and your main water heater. Desuperheater output warms this pre-heat tank, and your main water heater only needs to top up to the final temperature. The lower the incoming water temperature your main heater receives, the less work it has to do.
Our residential geothermal systems page covers how a desuperheater is incorporated into a new installation, and our geothermal maintenance guide covers the minimal annual checks the pre-heat tank requires.
For homeowners planning a geothermal installation in Edmonton or elsewhere in Alberta, adding a desuperheater at install time is significantly cheaper than retrofitting it later — typically $800–$1,500 added to the initial project versus $1,800–$3,500 for a standalone retrofit.
Full Heat Pump Water Heaters: Going Beyond the Desuperheater
A desuperheater is a passive add-on that relies on the geothermal system running. During milder weather — spring and fall, when space heating and cooling demand is low — the system runs less often and the desuperheater produces less hot water.
For homeowners who want to go further, a dedicated heat pump water heater can be paired with the geothermal system. Heat pump water heaters operate at 200–300% efficiency compared to 100% for an electric resistance element, and they can run independently of your space heating system. Pairing one with a geothermal system and desuperheater can reduce your water heating energy cost to near zero on an annual basis.
What It Costs to Add a Desuperheater in Alberta
If added to a new geothermal installation: $800–$1,500 for the desuperheater module and pre-heat tank, included in the overall project. This is by far the most cost-effective time to add one.
If retrofitted onto an existing geothermal system: $1,800–$3,500 depending on equipment, the location of your mechanical room relative to your water heater, and labour. Payback at $300–$500 per year in water heating savings is typically 4–8 years on the retrofit cost.
For a full picture of how a desuperheater fits into the total cost of a geothermal system, our Alberta geothermal cost guide covers all the components that go into a complete installation.
Frequently Asked Questions
Does a desuperheater work in Alberta’s cold winters?
Yes, though summer performance is better. During Alberta winters the geothermal system runs in heating mode, and while the desuperheater produces somewhat less output than in cooling mode, it still contributes meaningfully — typically providing 30–50% of domestic hot water needs during the coldest months. Over the full year the combined contribution is 40–70%.
Can I remove my gas water heater entirely if I have a desuperheater?
In most cases, the desuperheater is a supplement rather than a replacement. It provides pre-heated water but does not maintain a consistent 60°C supply on its own, particularly in winter. Most homeowners retain a backup water heater — either gas or electric. Some pair a heat pump water heater with the desuperheater system, which together can effectively replace gas water heating entirely.
Does a desuperheater require separate maintenance?
Minimal maintenance is required. The pre-heat tank should be checked annually for sediment and the anode rod inspected every 3–5 years. The desuperheater module itself is integrated into the heat pump and has no separate moving parts. The overall maintenance requirement is very low.
Is a desuperheater standard on Envirotech Geothermal installations?
Envirotech offers desuperheater packages on all new residential installations. Whether it is included or added at extra cost depends on the specific system and configuration — discuss this with the team during your site assessment.
Add a Desuperheater to Your Geothermal Plan
If you are planning a geothermal installation — or already have one without a desuperheater — the addition is worth seriously considering. Envirotech Geothermal has been installing geothermal systems with integrated hot water recovery across Alberta since 2006.
Contact the team to discuss adding a desuperheater to a new or existing geothermal system.
— Envirotech Geothermal | Alberta’s geothermal specialists — recovering every unit of energy your system produces, from ground heat to hot water, since 2006