DREG

Air permeability from SAP report

I think the specified room temps are incorrect: they should be 21C, according to NHBC TECHNICAL GUIDANCE 8.2/01. External temp should be -3.3C.

Asked for air test result but none found. Was sent the SAP report. The bathroom and en-suites have switchable fans with isolator.

Two further calculations…..

There have been other heat calcs done….. heat loss 29-1-25.pdf

I’m doing this retrospectively as house was built in 2021. I’ve been trying to get hold of the data but it’s like pulling teeth. I believe this is the heat calc that was used by the heat pump supplier/installer

If you have a heat loss/load calc that says 10.3 kW, what output heat pump would be recommended (new build house, EPC B) The MCS MIH documents don’t state clearly how many kW you need to allow for DHW and defrosting. Appreciate you do not want to oversize it; but equally is there a danger of under specifying it?

Thanks for that, John.

If the rad is producing 285 watts and the calculated total heat loss for the bathroom is 643 watts, does that mean the rad has been incorrectly spec’d? Or someone has not accounted for the corrected output.

Why would the inlet temperature be higher than the output temperature? That would give a negative answer to the Q (power) = Flow x SHC x (Flow-Rtn Temp)

Top to bottom. 60L buffer.

House has UFH on ground floor. Rads in bathroom, bedrooms and en-suites on upper floors. Flow temp into bathroom rad is about 37-40C. Screenshots of temp gauge on dining room (bifold doors) UFH manifold and the outlet/inlet temps on heat pump controller from yesterday.

Used 93kW in last 24 hours. Vast majority of that will have been heat pump; apart from lights, TV for a few hours, oven 1 hour, small electronic devices recharge. Outside air temperature between 0 and +4C.

Would it be possible for someone with knowledge of this to confirm these figures, please, in relation to an aluminium vertical radiator in a bathroom: Water temperature going into rad [flow in] is 40C and water exiting [flow out] is 35C. Average temp in rad is 37.5C. Target temperature of bathroom is 22C. DeltaT is 37.5-22= 15.5C DeltaT correction factor is 0.179 [from manufacturer] Radiator Output at DeltaT 60C is 1661 Watts [from manufacturer] Corrected rad output is 1661 x 0.179= 297.32Watts Many thanks.