We are seeing a few issues arise with the heating standard and heat pumps.

Too Small

The first issue is something we have addressed in previously – heat pumps that are too small are being installed because the Tenancy Services formula is not being used.

Owners with the best of intentions are getting the work done, only to come unstuck when the Tenancy Services calculator is applied.

We use the Tenancy Services calculator for all Healthy Homes Standards Rentfit Reports to ensure you know the exact kW that is required.

You can use the calculator yourself as well via this link.

It is also worth noting that if a heat pump is installed after July 2019, and it is too small, there is no allowance that we are aware of for that heat pump to be topped up using an electric heater. Our view is that the undersized heat pump may need to be replaced, so it is critical to get right the first time.

Don’t Use the Min - Max Range

The second issue that has arisen is customers using, or being advised to use a heat pump’s min - max range as the kW rating, which is incorrect and may result in the installation of an undersized heat pump.

Instead, you need to use the continuous kW rating of a heat pump.

We spoke to Mitsubishi Electric recently, and this was their advice:

• You should not use the min - max heating range to determine if an existing heat pump is big enough for the required kW.
• We should be using the single continuous heating kW rating, i.e. 3.7kW or 4.2kW etc.

The reason for this is that the heat pumps have a range they will operate in (min - max), but they are not rated to perform at those levels continuously.

They are rated to perform at the rating label kW on an ongoing basis, and that is the only kW rating we can use based on the Tenancy Services formula.

As an example, a Mitsubishi Ecocore AP42 has a heating capacity of 5.4kW and a min - max range of 1.3kW to 6.0kW.

Therefore, this heat pump can be used up to 5.4kW under the Tenancy Services calculator. You cannot use the 6.0kW rating and would need to use a larger heat pump if your calculation is more than 5.4kW.

• Kevan
• 29 October