It is now five months since we purchased a high-spec new build property that is heated by a Grant Aerona 3, 10.5kW air source heat pump system, and you can read our initial system review here. The property is situated on a fairly open, windy site, facing south on the edge of a village.
We were complete novices to air source heating systems (and of underfloor heating with individual room thermostats) and to be honest we found the overall setup complicated and complex. The control cupboard housing the hot water tank was a complete mystery, so we put our trust in the developer/installer that it was set up correctly and should not be touched.
We moved in at one of the coldest times of year, during minus temperatures in December/January. The system seemed to be eating electricity with costs much higher than expected and the underfloor heating performance was also disappointing with some rooms failing to get to temperature at any time during the day.
Being one of four new properties our neighbours were equally disappointed and frustrated. I used the Internet to research any other user experiences of air source heat pump systems and found My Home Farm which was very helpful. It was also worrying to read about other similar heat pump experiences consumers were facing.
I perused our technical specifications pack that came with the system and then emailed Grant UK directly to raise my concerns about running costs and general performance. Grant were extremely helpful and responded immediately offering to send an engineer to install a data logger to identify how our system was performing.
Two very helpful Grant engineers arrived and wired up our system to a laptop which remotely monitored the system’s performance. They returned after several weeks of monitoring and made the following changes:
- Removed lots of air from the system.
- Altered the position of pipework and the position of the pump into the hot water cylinder.
- Reduced the hot water timer control from constant to three times per day x 1 hour. They also increased the water temperature from 45 to 60 degrees.
- For the room stats, we were advised to reduce ‘set back’ times – basically leaving the system thermostats on, almost 24/7 to avoid ‘spikes’ when the heating comes on in the morning. For example, heating a cold slab can take several hours to get to temperature.
The data logger has remained connected following the changes made by the Grant engineers and we have been provided with a report ‘post’ changes. However, as the end user we are just pleased that our system is now operating much more efficiently.
Grant optimised the system performance, resulting in a much improved response time for heating the house and a lower running cost overall. They were further able to reassure us the system chosen by the developer was more than adequate for the house. The system is guaranteed for two years so that gives us additional peace of mind, and we will take up the Grant annual service plan.
The correct system set up is therefore imperative to ensure customer satisfaction and we feel very pleased that we received the support from Grant UK to optimise our system. We also changed energy provider shaving nearly 5p/kWh from our usage.
Provided this country gets to optimum green energy production, then systems such as these are better for the environment. Our calculations now show it is competitive against oil and LPG.