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Heat Pump Water Heater

Most homes still use fossil fuel or an inefficient electric system for water heating.  However, many people are now selecting super-efficient heat pumps to replace their aging systems.  Heat pumps can be three to four times as efficient as the older technologies and are often the best option for low operating cost & low impacts on climate.

Cost Range

$4,000 - $7,000

About the technology

Is it New?: Not really — heat pumps have been around for years. For example, your refrigerator is one, and air conditioners are also heat pumps. However, the widespread application to home water heating is somewhat recent in many areas.

How it Works: Heat pumps use electricity to move heat from one place to another, instead of creating the heat directly. This is what makes them so efficient when compared to conventional heating systems.  

Applicable Types of Heat Pumps: Various types of heat pumps are available to match a home’s particular needs.  For example, some draw heat from the ground, some from well water, and some (the great majority) from the ambient air.  Additionally, some are designed to just supply domestic hot water (such as for showers, etc.) and others also supply hot water for home heating through radiators or underfloor heating. 

Economics: Heat pumps are generally more expensive to install than a conventional system.  In many areas, however, incentives are available that can defray this additional cost. Additionally, you can often save money on your energy bills going forward, especially if you’re switching from heating with electricity, propane/LPG, or oil.   

Environment: Heat pumps are a great way to reduce your carbon footprint.  Their excellent efficiency, combined with the fact that they don’t burn fossil fuels, often lets them cut greenhouse gas emissions by 75% or more.  Plus, as grid-supplied electricity becomes cleaner, the percentage reduction will grow over time.

Frequently Asked Questions (FAQ)

1. What is a heat pump water heater (HPWH)?

Heat pump water heaters use electricity to move heat from surrounding air to the water cylinder instead of heating the water directly. This process makes them very efficient – typically three to four times more energy efficient than standard electric water heaters — and can significantly cut water heating costs in many cases. Heat pump water heaters have cylinder capacities similar to standard models, with the same range of temperature adjustments.

2. What types of HPWHs are available?

Heat pump water heaters generally fall into two categories – integrated and split-system models. Both use storage cylinders, unlike the tankless water heaters that are sometimes used in homes. Integrated systems are “drop-in” units that have approximately the same shape as a conventional cylinder water heater, but are somewhat taller to accommodate the heat pump. The split systems consist of a separate storage cylinder and the heat pump unit with a compressor (and associated equipment) that captures heat from the outside air. Split systems require some additional plumbing between the units.

3. Can a HPWH function in any climate?

Yes, they can, but you need to consider the type of HPWH and where it’ll be located.  Most HPWHs function well if the temperature in the area they’re located remains above freezing the great majority of the time.  If the temperature becomes too cold for the heat pump to operate efficiently, most HPWHs have backup resistance heating elements that can provide the needed hot water, but with greatly reduced efficiency.  It should also be kept in mind that a HPWH will cool the area in which it’s located, but this isn’t a wintertime problem if the HPWH is located outside.  

4. How much hot water is available for the household?

Heat pump water heaters come with different sizes. The most common capacities currently on the market range roughly from 135 to 300 litres. After being depleted of hot water, HPWHs (while operating in their efficient, heat pump mode) take longer to recharge than conventional fossil-fueled and electric water heaters.  Some professionals suggest replacing your old water heater with a somewhat larger HPWH to compensate for this.  For example, you might replace a conventional 180 litre water heater with a 250 litre HPWH.

5. What are the advantages of using a HPWH?

Heat pump water heaters use a proven energy-efficient technology. If you are switching from an electric or LPG-fueled water heater, a HPWH can reduce your ongoing water heating costs substantially.  If replacing a natural gas water heater, you’ll likely reduce your monthly water-heating costs, but the savings may be pretty small. If you also include a rooftop solar system, you can generate additional savings since the cost of the electricity needed to power the HP would be lower than the cost of grid-supplied power. Also, there’s an environmental advantage to using a HPWH.  When a water heater fueled by natural gas or LPG is replaced with a HPWH powered by electricity, your carbon footprint is greatly reduced.

6. Is a tankless electric water heater more efficient?

No. Tankless electric water heaters can be at most 100% efficient since they directly heat the water with electricity. A HPWH just moves heat (instead of creating it) and can be effectively 300-400% efficient.

1. How much does a HPWH cost?

The cost of a heat pump water heater will be higher than the cost of a conventional electric or fossil-fueled water heater, perhaps $2,000 or more than a conventional gas/LPG or electric water heater. Numerous site-specific factors affect the installed costs of a HPWH, so it’s always a good idea to get cost estimates from local professionals.

2. How much can I save on energy costs with a heat pump water heater?

It depends on a number of factors, especially the type of water heater you’re switching from and the energy prices in your area. If you’re replacing a conventional electric or gas/LPG water heater, you can cut your water heating costs substantially. If replacing a natural gas water heater, you’ll likely reduce your monthly water-heating costs, but the savings may not be as large.  If you also include a rooftop solar system, you can generate additional savings since the cost of the electricity needed to power the HP would be lower than the cost of grid-supplied power.

1. What are the steps needed to install a HPWH?

If you’re replacing an electric water heater with an integrated HPWH, the process is generally pretty straightforward. However, when switching from a fossil-fueled water heater, an electrician may need to run an electrical line from the main electrical service panel (or a sub-panel) to where the HPWH is installed. Regardless of the type of water heater being replaced, a split HPWH requires additional work since two components must be installed instead of one. 

1. What maintenance does a HPWH require?

Unlike conventional water heaters, heat pump water heaters use an air filter that needs to be cleaned periodically to ensure efficient operation. Other maintenance needs are similar to those of standard cylinder water heaters that operate on electricity or fossil fuel.

1. Can I save on carbon emissions if I switch to a HPWH?

Yes, it will reduce your carbon footprint.  The amount of the reduction depends on the carbon intensity of the electricity used to power your HPWH and the energy source (such as natural gas, electricity, etc.) you’re switching from.  If you add rooftop solar at the same time, the carbon footprint of running a HPWH is drastically reduced.

1. How do I operate a HPWH?

Heat pump water heaters are generally more interactive than conventional water heaters. Most models feature a control panel that allows homeowners to select water temperature and operation mode. Some are WiFi connected and come with a smartphone app. The app lets you control the HPWH and examine energy consumption patterns that can then be used to optimize the usage.

2. What is the warranty on a HPWH?

It varies, but major manufacturers of heat pump water heaters sometimes offer 6-year warranties on their products.