Why insulate
Why insulate your garage door
Why insulate your garage door, when most modern houses are insulated and double glazed and the largest opening in the building still misses out? Here is the honest answer on whether garage door insulation is worth it, and when it is not.
The garage door is the hole in the insulation
A single-skin steel garage door is a sheet of metal between your garage and the weather. It conducts heat straight through, it radiates it back in on a hot afternoon, and it does nothing at all for sound.
In most houses that would not matter much, except that a great many New Zealand garages are attached to the house and share a wall with a bedroom, a hallway or a living room. The garage is then a large, uninsulated buffer sitting against the heated part of the house.
Insulating the door does not turn the garage into a heated room. What it does is stop the garage swinging to the extremes, which is what makes it usable and what stops it dragging heat out of the rooms next to it.
The benefits of garage door insulation, and what actually changes
The garage stops being freezing in July and unbearable in February. It holds a steadier temperature, so whatever is heating the rest of the house works less against it.
This one surprises people. Insulation cuts road noise coming in and it makes the door itself much quieter to run. If a bedroom sits over or beside the garage, this is often the whole reason.
A steady temperature and controlled humidity is what stops condensation forming on the inside of the door and mould growing on whatever is stored against it.
On a .75mm door, insulation stiffens the panels as well as insulating them. The door feels more solid and drums less as it runs.
A gym, an office, a workshop or a rumpus room, rather than a cold concrete box you park in.
A garage that can be used as a room reads as extra space to the next buyer, which a cold garage does not.
When it is not worth it
We would rather tell you this than sell it to you.
If the garage is detached, unheated, used purely for storage, and nothing in there minds the damp, insulation on the door alone will not repay you. The rest of the building is still uninsulated, and the door is only one surface of it.
If the garage door is old and due for replacement anyway, retrofitting insulation to it is money spent on a door that is about to go. Wait and specify the new one insulated, which costs less than doing it in two steps.
If the real problem is a draught or water under the door, that is a seal, not insulation, and it is a far smaller job.
Common questions
Sectional doors, generally yes, whether they are new or already on the wall. Roller doors are a different construction and do not take panel insulation the same way, because the curtain has to coil into a drum above the opening. Send a photo of the inside of your door and we can tell you what is possible before anybody makes a trip out to look at it.
It will stop the garage being cold, which is not quite the same promise. Insulation slows heat moving in and out; it does not add heat. What people actually notice is that the garage stops hitting the extremes, so it is no longer freezing in July or unbearable in February, and it becomes somewhere you will spend time rather than somewhere you park.
It adds some weight, which is why the springs must be rebalanced as part of fitting it. Adding insulation without rebalancing is how people end up straining the motor and wearing the door out years early, and it is the most common fault we find on doors insulated as a DIY job. Done properly, the rebalancing is included rather than an extra.
If you are only doing one, the door is usually the bigger win. It is typically the largest uninsulated surface in the garage and the only one exposed directly to the weather on both sides, so it is where most of the heat moves. If you are converting the garage into a habitable room properly, do both, along with the ceiling.
It helps considerably, because condensation forms where warm moist air meets a cold surface, and a single-skin steel door is the coldest large surface in most garages. Insulating it removes that surface. It is not a complete answer on its own if the garage has no ventilation at all, but it is usually the single most effective thing you can do.
If the garage is detached, unheated, used purely for storage and nothing in there minds the damp, insulating the door alone will not repay you, because the rest of the building is still uninsulated. It is also the wrong spend if the door is old and due for replacement, or if your actual problem is a draught or water under the door.
From the bridge to the Brynderwyns
Talk to Chris, not a call centre
Drop us a line and we'll come back to you within 24 hours. Quotes are free and carry no obligation.
We're a family business. Chris owns it, quotes it and answers the phone himself, so you get a straight answer the first time you ask.