By the time your client has eventually decided to invest in a heat pump system, it is likely they have carried out a considerable amount of research.
If your client’s decision is driven by minimal land availability and/or cost, they will likely favour an air source heat pump.
Your client could have been enthused by “Stop-press!” styled statements in brochures, and pamphlets, or possibly been targeted by an over-enthusiastic sales person, who states an impressive “COP 4.2” or “COP 3.8”,while in the same sentence boasting output temperatures of +55°C and, in doing so, creates an unachievable expectation.
No matter which heat pump is chosen, or whoever the installer, the high COP figures stated in glossy brochures need a lot of living up to.
The heat pump manufacturer has, of course, every right to print the most attractive performance figures achievable, although the impressive results they claim are usually produced under ideal, stringently controlled test conditions.
Trying to achieve these performance figures in the field can be further compromised by less than text book conditions of the actual heating system.
There is, perhaps, far more sincerity in a manufacturer including output and efficiency data at substantially lower values, such as -2⁰C air temperature, and perhaps even 50⁰C output, meaning that clients will have no false expectations.
Under sub-zero conditions, don’t be surprised if the efficiency is below COP 2:1 and that the rated output of the unit is no longer a boastful 14kW as advertised, but perhaps low as 8 or 9kW in reality.
It is the responsibility of us all to ensure that we retain our rightful place as providers of a good, sound, economical, renewable-energy heating solution.
Therefore, we need our customers to get exactly the result they anticipate, and not some over-stated, unachievable target.