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There are quite a few factors to consider here if your expectations are very high for insulation but some basic advice is easy to explain for most requirements.
The first thing to remember is to make sure that if you require a specific 'U' value (measurement of insulation) achieving for your garage then you need the 'installed' 'U' value and not the common quoted value of a piece of the panel used, this is very misleading, so beware.
The 3 best mainstream garage door types for insulation in order of performance are:
Sectional Garage Doors
Side Hinged Garage Doors
Roller Garage Doors
There are some good round the corner doors and also sliding doors with excellent insulated panels too but for mainstream garage doors we are looking only at the 3 above as a comparison.
Sectional Garage Door - This type of door can be purchased usually in 20mm or 40-45mm double skinned steel door panel sections with a foam core insulation inbetween. As the sectional door operated in a vertical plane the panels can benefit from rubber weather seals all around the fixing frame adding to the weather protection properties of this door. The only way however to get the full benefit of an insulated sectional door is to install the door BEHIND the structural opening so the door panels overlap the garage piers and lintel effectively giving a 'thermal break' and continuing the insulation offered by the garage walls itself.
Each panel on a good quality sectional door will have a rubber seal embedded in each of the profile joint sections to give the best possible seal between the individual panels and combined with seals on all sides including a large seal on the bottom panel you can achieve the best U value if installed correctly. Additional seals are now also available on Hormann LPU42 doors to increase insulation further by up to 15%.
Insulated Side Hinged Doors - Side hinged doors have always been capable of offering high levels of insulation, just think about a freezer door, what is is? Hinged of course. Up until recently however no manufacturer had put in the effort of a double skinned, foam filled steel door set with rubber seals on a rebates edge all round. With a bottom edge threshold also with a seal built in you stand a chance here of a pair of large garage doors effectively sealing an opening very well indeed.
These are the Carteck Side Hinged doors and they are all made to order with an aluminium fixing sub frame included and high quality stainless steel furniture.
Of course properly installed GRP and timber side hinged doors can also offer pretty good insulation and you only need to get the right seals to make the doors weather resistant too. Take a look a the Woodrite Timber for a full range of options. Call for advice and prices if you are struggling.
Insulated Roller Garage Doors - The term insulated roller door is used to generically describe most aluminium roller garage doors sold in the UK. As we make no issues in constantly reminding people with roller garage doors that you really do only get what you pay for then you have to remember the same with insulation properties on these doors.
A good quality foam filled aluminium roller door will give good levels of insulation if installed behind the structural opening like the sectional door does. A cheap, poorly constructed double skinned roller door using inferior aluminium slats will not give much insulation and worse still will probably give you all sorts of headaches with rattling and motor problems - enough said, again!!
A roller door by its very nature is difficult to get a proper 'U' value for once installed as technically there is a gap, albeit small, between every slat and there are about 21 slats in the average height door. Install the door behind and add a full hood and you will definitely feel the benefits in the winter months however.
Good sized guides and slats with a thickness of about 20mm is about as good as you will get for a domestic garage door.
Take a look a the Seceuroglide Roller Door for one of the best roller doors in the UK.
The Hormann Rollmatic is also a winner as well as the Gliderol aluminium roller door.
If you are unsure then give us a call on (01926) 463888.