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Benefits of upgrading windows in sunroom?

  • 18-01-2023 10:17am
    Registered Users Posts: 27

    Hi all,

    We are living in a house constructed in 99. All the dates on the windows are 99 and are double glazing. Probably old munster joinery UVPC (Euroseal 99 with the metal strip between panes). Anyway, the frames and windows are generally ok BUT the house is an older build so overall insulation standards are poor.

    One problem area is an old sunroom. We've previously updated the room (rockwool and 100ml board) which made a HUGE difference and also pumped the lower walls. However, there is still a good 3-6 degree difference between it and the rest of the house a few hours after heating is switched off. So its a drain on heat. Im going to rent a thermal camera BUT one suggestion was to replace all the windows and doors due to their 20+ year age. Key question, would this be worth it? The windows account for about 60/70% of wall space so I assume so. Im not really fixated on payback but rather comfort and also lowering footprint etc. We were looking at double and triple glazing options with U values as low as 1 and .8 and I assume our existing ones (minus drafts and inefficiencies) are around 2.5-3 in terms of U value. Any ideas or experiences of glazing upgrades and is the change significant in terms of room performance etc?

    Any perspectives welcomed.


    ps: We have doubled attic insulation, internally lined some rooms with 100ml boards, and are in the process of adding an A rated door etc. So windows are the focus now.

    Post edited by DazzaMazza on


  • Registered Users Posts: 2,756 ✭✭✭MicktheMan

    Yes changing your windows will make a big difference to your comfort as well as room temperature but only if you go for units with certified uvalue of 0.8 w/m2k or better (lower), are installed properly (airtight materials used internally to seal the frames to the reveal walls, heads and sills) AND the room's airtightness is good.

    Generally, if the windows have passive house certification they are good enough.