Agree with Eddie - we had a fibreglass up and over door which was worn out (got through two sets of springs - when they break under tension you don't want to be nearby). Decided to go for the insulation benefit (partly as our garage is integral to the house) and settled on a Hormann sectional insulated door (no links just happy customer).
The insulation (about 20mm from memory) and the much improved sealing of this type of door - edges and top and bottom -
has made a big difference - the garage (and the room over) keep much warmer in cold weather and are now virtually draught-free. The Morgan is now in this garage
Totally agree there is a loss of height - but, for me, working in the (relative) warmth in winter is a big advantage
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