Is temporary / partial internal wall insulation worth doing?

ComicGeek

I would say that your 7000 BTU rads are far too small. Hard to calculate from the floor plans, but if the family room is 6m x 7m with the additional kitchen recess on top of this, this could be at least 50m2. Even a very good level of insulation in this size of space (and very good air tightness as well) would need at least 60 W/m2, so that would be 3 kW minimum. Add on top the internal rated door to the unheated utility room which will just be leaking heat, and you may nearly be half what you actually need in that room in the current situation.

I would upgrade the rads (after doing a more accurate heat loss calc) - then I would either turn the heating on in the utility room (but at a lower temperature) or replace the internal door for an external quality door.

Insulating the garage wall isn't going to make any significant difference.

markin

It will be the internal door that should be external not the original house walls.

ThisIsWeird

ComicGeek said:

I would say that your 7000 BTU rads are far too small. Hard to calculate from the floor plans, but if the family room is 6m x 7m with the additional kitchen recess on top of this, this could be at least 50m2. Even a very good level of insulation in this size of space (and very good air tightness as well) would need at least 60 W/m2, so that would be 3 kW minimum. Add on top the internal rated door to the unheated utility room which will just be leaking heat, and you may nearly be half what you actually need in that room in the current situation.

I would upgrade the rads (after doing a more accurate heat loss calc) - then I would either turn the heating on in the utility room (but at a lower temperature) or replace the internal door for an external quality door.

Insulating the garage wall isn't going to make any significant difference.

It's certainly not overkill!

I was taking their family room size as being "4m wide at the back with 3.2 sliding door and 0.8m window", which would make it roughly 4m x 5.5m?

We've had a 6x6 extensions built, with nearly 4m of bifolds, two windows, and two sky lanterns. It is heated - successfully, to the required 20oC - using just two vertical column rads of 3700btu each. Mind you, it is not open to any other room (unless intentionally).

Yes, 7k btu might well be on the low side for this extension, but I don't think critically so. Depends on how warm they want it, I guess?

DRP

thanks for the additional comments. I think you might be right about the rads plus the door/drafts.
The extension is almost exactly 5x5m.

it's a bit annoying that it's getting warm now, so will be difficult to investigate until the end of the year