Doors and Windows - Aluminium window replacement

Hi - I'm thinking about replacing my original (late 60's) sliding aluminium windows. My house has a Stucco exterior. I believe retrofit vinyl windows are a common option, and (relatively) easy enough to install into these frames.

But surely the aluminium sill (on the interior) act as a thermal conductor, and so make spending all those $'s on efficient glass and frames wasted? Is a better solution to completely remove the aluminium frame (does it have to be pried out? the sill and fins appear to be bonded to the wall)? In which case, can you still use retrofit windows?

Thanks,
Mark

('aluminium': yes, I'm English!)

yes for sure remove sills and tracks.easy way to do this is take a sawzall and cut one of the vertical legs then just pry it out

Not to be contrary, but no, it is not necessary to remove the aluminium frames, depending on how they are dealt with. The vinyl windows that we retrofit have an exterior and an interior trim, and are usually sized to slip inside of the existing frame. The exterior trim is cut so that we can caulk it to either the siding or the existing frame and get a water-tight seal. Once the window is in, and before the interior trim is installed, we put insulation in the space between our window frame and the sill. This essentially eliminates any thermal transfer of heat or cold by the original aluminium frame. Then we apply the interior trim. Depending on what the original windows were, we can reduce a customer's energy consumption by 20% to 50% by simply retrofitting their windows. Usually, and especially with a stucco exterior, we prefer to seal the windows to the original frame, rather than to the stucco. If you hold a 4' level against a stucco wall, and look at the gaps between the level and the stucco, you'll understand why!! An aluminium frame is straight and flat. Stucco isn't!!

Do you not bother removing the fins around the sides of the frame? Presumably this gives you a nice space to fill with insulation.

The thermal transfer problem I maybe didn't explain very well: The bottom sill in most of my cases is an aluminium sill the depth of the wall, flush with the interior, and in cold weather is as cold as it is outside. If this is simply covered by trim, that doesn't seem like much in the way of insulation. I was wondering if this part would be best removed somehow.

Thanks again,
Mark

Hi, Im English too I live in Jersey Channel Islands, if the ali frame is not thermally broken then it will conduct the cold through the frames so yes remove them, Use a stanly knife to cut around the inside of the frames to break the seal where the plaster is stuck to the frame, on the outside use a hammer and bolster to chop around the frames to make a 5mm/1/6th gap, remove all the fixings from the frames, use a crow bar to get under the sill and prise up then use a hack saw to cut through the frame then pull either side inwards towards the middle of the frame this should release the sides then pull one side in to bring the head down on one side, if the head is tight then cut through this to rhat should allow the frame to come out with hardly any damage to the surounding reveals.........