Insulate between Floors

west side kid

Hello

Currently renovating a large period house - we are going to max out on ceiling insulationg - but the builder has suggested insulating _between_ the 1st floor (ground) and 2nd floor.

We are lifting the floorboards anyway so he says it won't cost too much. I am leaning towards doing it but wanted insights from the experts on here.

Our logic for doing this would be that on our main ground-level floor we have large rooms with really high ceilings (3.5 metres) that I suspect are ice-boxs in winter. If we insulate above them:
- they will heat much faster
- retain their heat much longer

We are also doing zonal heating - with different zones for the bedroom/sleeping level and for the downstairs (living area) - with different temperatures and timesettings for the Rads.

I understand at some level that insulating between floors doesn't necessarily decrease the heat leaving the house as a whole - however it might allow us to retain it where we want it?

Any advice? I have seen very little on the web to guide on this. I know there is no BER upside from doing this?

Perspectives welcome.

shane0007

I would definitely insulate them. There is an argument that any lost heat would be gained to upstairs but the heating for that room is sized to heat that room only & it will reach temperature quicker if it has limited losses.

antoinolachtnai

I don't know if I am an expert, but the good reason to insulate these is to deaden down sound to make the bedrooms quieter whilst the downstairs is busy. This is worth doing when you have the opportunity.

There is no economics in doing this for saving heat. The temperature differential between upstairs and downstairs is too small. Insulation only really matters when there is a big difference, i.e., between inside and outside.

blacktea

I would suggest ensuring the external envelope is insulated properly first as heat will escape through the walls very quickly if un insulated in comparison to the internal floor. Heat will flow out through the coldest areas.

Your principle is correct though- installing insulation in the ceiling/floor will hold the heat in the room but it will tend to push more heat out through the walls, windows, other poorly insulated elements