Hi, heat pumpers. Last summer I used Heat Punk to get a heat loss estimate for heat pump and and rad sizing while I was waiting for my heat loss surveys.
My house heat loss came out at 4.6kW (-2.7C out, 21C in). The final installer used Heat Engineer and came to a very similar figure and has since installed a Vaillant Arotherm+ 5KW system which seems to be performing very well. In fact a lot better than expected.
Revisiting my Heat Punk project, I now see Heat Punk have several options for the air change calculation. The calculated heat loss value has now dropped from 4.6kW to 3.8kW for the same setup.
Maybe I missed the option before - so my error, otherwise something new and in line with what
has been acknowledged for a while re air change rates.
Hi Rob. Yes I did, but a bit late for me as the system was installed before they changed it.
Iām just an end user not an installer.
I revisited the project out of interest as I was thinking the original heat loss calculations done using Heating Engineer were possibly too pessimistic as the numbers estimated from my monitoring where showing much lower figures.
When I logged back into Heat Punk and selected the project a new pages popped up asking me if I wanted to go with the existing ventilation estimate or a new one based on location, wind speed etc.
I chose the new one with the average location and exposure. It then automatically updated the heat pump calculation showing the new lower figures.
It did not change the selected system (Arotherm plus 5kW) which I think is fine. The 3.5kW would have been too close to the heat loss. A 5kW system gives a 30% oversizing, which is better than the original estimate which showed only a 1% oversizing. I believe the installer was using the peak output of the Arotherm 5kW of 6.5kW rather than the real world achievable with defrosts etc. which is probably close to the badge output.