Radiator BTU Calculator help for breeze block house

yonaled

Hi, we trying to upgrade the radiators in our new home adn after some resaearch have found out that cityplumbing.co.uk are one of the best at calculating BTU's.

Unfortunately our house, built in 1961, is completely made from breeze blocks (inside and out) and concrete/wood clad so was looking for advice. I guess my options in the calculator drop down menu for Type of Construction are 'Brick Cavity' or 'Insulated Brick Cavity'
We have just had the place fully insulated (walls and loft) but wondered, due to the breeze blocks lack of insulation properties, if we should just select the 'Brick Cavity' option in the calculator? Or maybe it's better to add or minus a percentage of the total. Bear in mind that our living/diner is 7m long and we have large cold dual aspect single glazed windows of a total of 7.6 sqm so a miss calculation could be very breezy or very expensive in bills depending which we we got the numbers wrong!

If you google image '1 Burnville' our house is the first image - big windows, trees on the left for further info. PS there is no gas fire in there anymore for extra heat output!


Any help appreciated