Garage Door Insulation: Does It Suit Your Door and Your Home?

Question 01

Can you insulate a garage door?

Usually, if it's a sectional door. Steel-Line says sectional doors can be made with insulated panels, and its Mammoth insulation panels are fitted to the back of doors in its sectional range. Standard roller doors are the exception. Steel-Line says they can't take insulation panels because the curtain has to roll up around the drum.

Whether insulation can go on an existing door also depends on the brand. B&D says its insulation can't be retrofitted to an existing door and has to be fitted when the door is bought. Steel-Line describes its Mammoth insulation as retrofitted polyester fibre panels and says it can be installed on its sectional range. So the honest answer for an existing door is to check with that door's maker first.

For a roller door, the closest thing to insulation is stopping draughts. Steel-Line says roller doors can be fitted with weather seals and stripping to stop draughts. That helps with draughts, but it doesn't stop the steel curtain heating up in the sun. If you're still choosing a door, roller vs sectional vs tilt garage doors compares the three on space, noise, wind and insulation.

Question 02

Is garage door insulation worth it on the Sunshine Coast?

It's worth it when the garage is part of the house. If there's a bedroom above, a rumpus room beside it, or you use the garage as a gym or office, insulation helps with heat and noise. B&D recommends it for garages used for more than the car. For a separate car shed, it matters far less.

Insulation is more likely to pay off if:

• The garage sits under the house or shares a wall with a bedroom or living area. B&D says insulation reduces sound transfer to other parts of the home, which helps if there's a bedroom above the garage.
• You use the garage as a home gym, office, workshop or kids' room. B&D recommends insulating the door in that case.
• The door faces the afternoon sun and the garage gets hot. Steel-Line says its insulation keeps a garage cooler in summer and warmer in winter.
• Traffic or neighbours are loud. B&D says its insulation cuts outside noise by 18dB, double the reduction of its standard uninsulated Panelift door, based on an independent test by Acoustic Logic.

It's less likely to pay off if:

• The garage is a separate shed for the car and the mower.
• You have a standard roller door, which can't take insulation panels anyway.
• The garage walls and roof aren't insulated either, so the door is only one part of the heat coming in.

On cost, B&D says insulated doors can cost more upfront but can save money over time through lower energy use. How much depends on whether you heat or cool the rooms near the garage. A garage door is only one surface, so don't expect it to do the job of roof or wall insulation.

Question 03

Does insulating a garage door make it too heavy?

It can change the door's balance. Garage door springs are set to carry the door's weight, so anything added to the panels changes the load they carry. B&D puts a typical sectional door at 80kg to 150kg. After insulation goes on, have the balance checked, and never adjust the springs yourself.

B&D says garage door springs exist to counterbalance the door's weight, so you can open and close it with little effort and the motor isn't doing the lifting. It also says that without working springs, the motor does all the heavy lifting, and that's when breakdowns, misalignment or injury can happen. A door that's heavier than its springs were set for puts that extra load on the opener.

How much weight insulation adds depends on the product. B&D describes its own insulation as slim-line and says it won't affect the weight of the door as it's raised and lowered. Other panels and kits are different, and the door's springs don't know which one you chose. Signs the balance is off after insulation goes on:

• The door feels heavy and resists opening, even with the opener running. B&D lists this as a sign the springs are losing tension.
• The opener sounds like it's working harder, or slows down part way. B&D says springs are there to reduce strain on the motor.
• The door rises crooked or one side lifts before the other. B&D says an uneven door often means one side of the spring is weaker.

Question 04

Which is better, polystyrene or polyurethane garage door insulation?

Neither is better by name. Compare the R-value printed for the product at its thickness instead. B&D says garage door insulation is usually polystyrene or polyurethane foam. The Australian Government's YourHome guide lists both as rigid board insulation, each rated by its R-value at a stated thickness. Foil kits work differently again.

YourHome explains that bulk insulation is sold with an R-value for the product at its stated thickness, and that doubling the thickness of a material doubles its R-value. So a thin board of one foam can be beaten by a thicker board of another. Compare like with like: the R-value, the thickness, and how the panel fixes to your door.

Foil is the odd one out. YourHome says it mainly resists radiant heat and relies on a still layer of air beside the shiny face. A foil sheet glued flat against a steel panel has no air gap, so check how a foil kit is meant to be fitted before you rely on it.

Question 05

What R-value do you need for garage door insulation?

There isn't one number every garage door has to hit. R-value measures how well insulation resists heat flow, and a higher number means more insulation. Makers publish their own figures, such as R1.09 for Steel-Line's Mammoth panels. Compare products on that number, check it's an Australian one, and for a new home ask the builder what the design calls for.

That last point trips people up when shopping online. YourHome says Australian R-values are metric and different from United States R-values, and that American products quote R-values that look much higher than Australian ones. Look for the metric value on a product labelled as meeting Australian standards, not a big number on an imported kit.

YourHome also says insulation materials sold in Australia must meet AS/NZS 4859, and reflective materials must meet AS4200.1. And the number on the pack isn't the whole story. It says compressed bulk insulation, dust on reflective foil and a missing air gap all cut the real R-value, so fit the product the way its maker says.

Question 06

How can you tell if a garage door is already insulated?

Look at the back of the door from inside the garage. An insulated sectional door has a solid backing over each panel, or foam or fibre panels sitting in the panel frames. An uninsulated door shows bare steel on the inside. A roller door is almost always uninsulated unless it's made of insulated slats.

• Check the inside face. Bare steel with ribs or pressings showing means no insulation. A smooth backing, foam board or fibre panel over the steel means some form of insulation.
• Tap a panel gently. An uninsulated steel panel usually sounds hollow. An insulated one tends to sound duller.
• Feel it on a hot afternoon. If the inside face is nearly as hot as the outside, the door isn't holding much heat back.
• Look for a label or paperwork. Find the maker's name on the door, the opener or the house paperwork. The maker can tell you whether that model was insulated.

Moved into a house and don't know the door's history? Note the brand and the model before you buy anything for it. B&D, for example, says its insulation can't be added to a door after it's bought.

Question 07

What's the difference between an insulated garage door and an insulation kit?

An insulated door is built with insulation in its panels at the factory. A kit is foam, fibre or foil fitted to the back of a door that's already up. With a factory door, the springs are set for the insulated panels from the start. A kit can change the weight the springs carry, so have the balance checked.

Makers handle this differently. B&D says its insulation has to be fitted when the door is bought. Steel-Line says its Mammoth insulation can be installed on its sectional range. Whatever kit you look at, the fit depends on measuring each panel and fixing the boards so they don't rub on the tracks, rollers or hinges as the door folds.

YourHome's guide to insulation says it's vital insulation is installed correctly to perform well and avoid condensation problems. On a garage door, there's one more test: the door still has to open, close and balance the way it did before.

Deadlock doesn't supply or fit insulated doors or insulation kits. Thom works on sectional, roller and tilt doors, and a garage door service checks spring tension and balance, so it's the right booking if your door feels different after insulation goes on. Repairs and servicing are booked as a callout valued between $200 and $300, depending on the door size and the labour involved.

New doors from Deadlock: Only work valued at $3,300 or less.