Vinylbilt windows

[sii]

Hi all,
I haven't been on this board for a while....life. LOL

3 summers ago we had vinylbilt windows installed throughout the house. My orchids sit by a southeast window and always did well. I haven't seen any flowers since, but at least they are not dead.
I've changed the medium when it needs it and fertilize with Schultz.

Any advice?

[SundayGardener]

Don't all the newer type residential windows have UV filters in them?

[Gil]

Perhaps your new windows are not allowing a sufficient cool down in winter? My phals live on 20 ft. of window sill in winter on a SE side of the house. The room is just semi-heated and a thermometer on the sill will record temperatures in the mid to upper 50's in winter and sometimes lower. They usually all spike in the spring with some still blooming now.
Perhaps a thermometer check may show your temperatures staying higher than they like for spiking. Just a thought.

[Ray]

Are they Low-E windows? I suspect so, as that offers significant energy savings.

Low-E coatings are designed to block long-wave infrared (heat) and UV, but other than that, the transmitted spectrum is changed extremely little. The primary impact on plants is a general reduction in transmitted light intensity, which can be reduced anywhere from 25% to 50% compared to uncoated glass. The human eye adjusts well, so it's hardly noticeable, but chlorophyll doesn't.

That's likely your problem, so supplementation with artificial light sounds like a good remedy.