Heat Loss Cals - Floor Temp and Empty Unit below.

Hi All.

On the recommendation of a few here I am using the Kermi Heat Loss calculator which I have found to be great once you put in the time and know the building construction but I do have one query.

I reside within a first floor apartment with my own ground floor entrance, only two floors, first and ground. Floor construction is uninsulated 6" slab with screen and uninsulated ceiling below.

I am sizing for a gas installation at this moment in time and the apartment below is remaining electric which means rooms are heated as needed. How would you experts allow for this in you calculations. I have read some conflicting reports.

They are...
1: A radiator system will send so little heat to the floor it's not actually an issue.
2: Use the outside design temp for the floor.
3: Set a common temp say 10 or 15c.

The issue I have I currently have the temp set to 15c but if I set it to say 10c which I believe is possible as they let their water freeze over the cold spell meaning internally parts of their unit got below 0 then the required btus actually exceeds those if I set the floor temp to the outside design temp of -3.

Any recommendations would be appreciated.

how can the heat requirement go up if you assume the space underneath you is as cold as outside, in reality it wont be as cold as outside so possible assuming 8-10 will be more realistic, but if you want to be sure your requirement is met treat it as outside and you cant go wrong

Hi,

I believe it goes up higher as the main heat loss of a ground floor is at the edges hence in new builds its all about an insulation envelope. So the heat loss at -3 at the area of outside parimeter i.e a straight 36m is less than a 13c differance over a full 84sqm. Hence the problem . From what I have read I believe that is the case.