On Saturday, February 7, 2015 at 2:54:25 PM UTC, DerbyBorn wrote:
Just wanting a bit more output. Could go higher but not wider.

However, a new back door might warm the room up a bit as it is single
glazed and thin ply bottom panel.

We have external doors like that, although double glazed. They were thick enough for me to add a second panel on top of the other separated by bubble wrap. I don't know how much extra warmth it has added but it all helps.

Jonathan