LG Therma V 16kW

I installed an LG Therma V 16kW ASHP in 2020 to replace our old oil boiler in our listed building. Although listed buildings typically don’t require an EPC, we needed one to qualify for RHI payments, which were crucial for us. Thankfully, a new extension helped us achieve a D rating in March 2020, even before installing the ASHP or adding extra PV solar and batteries. Despite these upgrades, it’s unlikely our rating has improved beyond D. The RHI payments, which have now been replaced with a grant, are increasing with inflation and are expected to cover most of the installation costs.

However, there were some issues with the installation. Firstly, the installer didn’t discuss or set up the operation with weather compensation (AI). Moreover, they installed the controller in a warm bathroom, rendering its ability to monitor internal temperature ineffective. They later explained that they set a high flow rate (55C) to mimic traditional central heating and avoid callbacks, which misses the point of the ASHP’s efficiency.

I took matters into my own hands and, with help from Renewable Heating Hub’s forums and LG User Group on Facebook, set up AI in winter 2022/23. It’s been working splendidly, maintaining main rooms at 21C at a much lower cost and power usage. We’ve set a slight setback of just 1 degree overnight in winter. Less used rooms and bedrooms are kept around 15C. Now, the flow temperatures are typically in the low 30s, rarely going above 40C, even on colder days. We’ve set the hot water to 43C, which is more than sufficient for our needs, and we run a Legionnaires cycle once a week.

A downside is our controller provides limited information, and it seems impossible to upgrade its software/firmware. So, details like SCOP are unavailable to us. Later controllers apparently offer better information.

A note for those in listed buildings: it required a planning application, which was a bit of a hassle as the planners were not initially helpful, but it was eventually approved. I managed the application myself, without an architect, using self-drawn plans.

My recommendations would be to ensure the ASHP’s location doesn’t cause noise issues for you or neighbours. If possible, place it in a sunny location to reduce power usage, but be mindful of noise and visual impacts. Also, consider the need for maintenance to meet warranty requirements, even though the annual cost seems high for what seems like minimal work.