The size of hot water heat pump you need is primarily determined by the number of people in your household, as this impacts your hot water usage.
According to the Heat pump hot water size guide from Pure Plumbing Professionals, you can use the following table to determine the appropriate system size based on the number of occupants:
| Size | Capacity | Maximum/Minimum People | Off-peak Tariff Suitability |
|---|---|---|---|
| Small | less than 200L | Maximum 2 people | Not normally suited to off-peak tariffs |
| Medium | 200 - 300L | Maximum 3 people | May not be suited to off-peak. Some can run on Restricted hours tariff |
| Large | 300L+ | Minimum 4 people | Restricted hours and off-peak tariff possible |
How to Determine Your Size
To figure out the correct size for your needs, simply look at the second column in the table and find the row that corresponds to the number of people living in your home.
- For up to 2 people, a small heat pump system (less than 200L) is generally sufficient.
- For up to 3 people, a medium system (200 - 300L) is typically recommended.
- For 4 or more people, a large system (300L+) is usually required to ensure enough hot water is available.
Considering Off-Peak Tariffs
The guide also mentions suitability for off-peak electricity tariffs. If you plan to run your heat pump on off-peak or restricted hours tariffs to save on energy costs, this can influence the required tank size. Larger tanks (300L+) are better suited for these tariffs as they can heat a large volume of water during the off-peak period to be used throughout the day. Smaller systems are generally less suitable for relying solely on restricted hours.
[Hot water system sizing]
