My UFH quandary and mystery.....

[Bonner]

18 hours ago, micheal300 said:

sash windows with 4-8-4 double glazing

 

When you say sash windows, are they sliding sashes? These can be challenging to seal effectively, even modern ones. Also an 8mm air gap in double glazing is very weak by modern standards.

[Olf]

16 hours ago, WWilts said:

Our SAP expert advised that solar panels would improve the energy efficiency much more than insulation improvements

This is 'efficiency' from SAP score perspective and have little bearing on thermal comfort. Also efficiency is one thing, maximum output available (needed do maintain desired temperature) another: dial heat pump temperature down to improve COP and on cold morning it will not maintain comfort any more. Dial it up on a frosty day and even if flat out (and rubbish efficiency) it may not be enough to bring in more heat than comes out.

[micheal300]

5 hours ago, Bonner said:

 

When you say sash windows, are they sliding sashes? These can be challenging to seal effectively, even modern ones. Also an 8mm air gap in double glazing is very weak by modern standards.

Yes, hardwood sliding sashes

 

I’m checking out the possibility of replacing the glazing for higher performance glazing

[WWilts]

8 hours ago, Ferdinand said:

Are you sure he didn't mean improve either a) the EPC number or b) the environmental impact, as solar panels don't really reflect on energy efficiency, as they generate extra free, clean clergy which is pumped in?  Solar panels are a well-known EPC level dodge.

This. EPC improvement

[gravelrash]

If the floor is 24c then water flow temp is obviously heating slab to adequate temp.

My underfloor heating only has 50mm pu underneath a 130m2 slab with 40c flow,  upstairs rooms of 100m2 not requiring heating , barn conversion in 2004 so not the best insulation at all, 20mm glazed units to oak frames and no airtightness to speak of plus sat facing shittiest westerly weather and winds -but house still gets toasty and only uses £70 in gas a month during winter months...might be different this year  So def something amiss with your fabric