MartynP

Hi all, I had a Mitsubishi Ecodan 8.5kw and Mitsubishi pre-plumbed 250L tank installed a few months ago. Although I did the research on installers and read many reviews in the process I did find an installer I believed was good, well the install was good but let's just say the after sales advice is somewhat lacking. A bit of background, I live in the south east in a 4 bedroom three bathroom house, as I've extended it over the years. It's a 1985 construction with double glazed UPC doors and windows, cavity wall installation, and approx 300-350mm of loft insulation. The house is all radiators that are K22(?) type, double paneled with 2 sets of fins and the heat loss calculation shows they are the right size for the house and ASHP, I'd also say we are reasonably air tight with no drafts anywhere. After a number of visits post install it was left on weather compensation mode and the LCD display showed it had been set at +9. However, the house never seemed to get warm so after a call to the Mitsubishi customer help line they said the best setting would be flow temperature and suggested trying around 45 degrees. Using MelCloud I've been trying to keep track of how much it's costing for heating, especially as my supplier went bust and below is what I've been recording. The outside temperature is from a temperature logger I bought off Amazon for about £15 and records the outside temperature every 10 minutes or so Date Consumed Delivered Ave Temp SCOP 16/12/2021 12.8 51 11.9 4.0 17/12/2021 16.1 70 8.5 4.3 18/12/2021 16.6 68 8.7 4.1 19/12/2021 14.8 62 5.3 4.2 20/12/2021 18.7 84 6.6 4.5 21/12/2021 21.2 88 5.8 4.2 22/12/2021 27.8 92 2.2 3.3 23/12/2021 18 79 8 4.4 24/12/2021 15.3 64 8.6 4.2 25/12/2021 21 82 6.7 3.9 26/12/2021 19.9 76 7.2 3.8 27/12/2021 21.9 81 9.8 3.7 I've struggled to work out if weather compensation or flow control is the best from a comfort/cost perspective. Despite reading a number or articles or watching youtube videos I've also struggled how to set up weather compensation so it heats the house sufficiently. Can anyone who has experience of this setup advise in the real world what I should be aiming for? Thanks in advance Martyn