heat retention with extension with bifolds

tired_dad

So we are looking at a 7m x 4 m extension at the rear. It will be 2 stories. On ground floor there will be a living room (taking up the whole 7x4 footprint) open planned into an existing dining room.

We are planning about 3m of glass on one wall and 5m of bifold/slider on the other.

We want the room to be for all year round use and to feel part of the house.

Using modern double glazed units how effective should I be expecting heat retention to be.

I would hate to spend a lot on a room that is so cold in the winter that it becomes functionally unusable.

Thoughts welcome

Doozergirl

It will be well insulated in the floors, walls and ceilings. Choose extra insualting glass. Bifolds are not airtight so will let in more air than windows or patio doors. How comfy may depend on the rest of the house. We've had huge extension rooms and two sets of bifolds across the back of the house and were plenty comfortable in winter. We had good curtains and the whole house was insulated well and there was a new boiler and rads so that was always going to help.

Don't forget you need somewhere to put furniture!

vaio

I'd have thought if it gets through building control then the heat loss numbers will be ok, the rest is down to your heating system

globalds

you could push for triple glazing on the 3m section with solar glass.

If you can wait a day I can try and get you a bi-fold manufacture who is reasonably high on airtightness..They are notoriously tricky to keep a good seal on.

lackingwedge

I am looking at something similar to an existing extention to my kitchen area. Any information you can come up with Globalds will be most welcome.

andrewf75

Am having similar concerns with our 5x6m extension with 2m bifolds and 3x2m roof lantern. But as has been said here, it went past building control ok and architect only specified double glazing for the lantern. I have been agonising over going for triple, but have now convinced myself it isn't worth it.

Doozergirl

I don't think triple glazing is worth it unless you go all out for highly insulated frames. There is a point at which the frames, because they generally aren't insulated, compromise the u-value of the window and make them not cost effective.

Bi-folds are necessarily draughty, just not airtight, which probably isn't good for most of the houses they go into anyway. The way we build houses in the UK, they need draughts.

Inch_High_2

andrewf75 wrote: »

Am having similar concerns with our 5x6m extension with 2m bifolds and 3x2m roof lantern. But as has been said here, it went past building control ok and architect only specified double glazing for the lantern. I have been agonising over going for triple, but have now convinced myself it isn't worth it.

2 metre bifolds, are they worth the effort and cost over French doors?

andrewf75

Inch_High wrote: »

2 metre bifolds, are they worth the effort and cost over French doors?

I did wonder at one point, but we like the idea of opening the space up completely. To be exact they are 2.35m