Garage door insulation kits

An EPS door kit cuts about 16 %CComputed by our engineinsulateFirst() 'door_kit_eps' measure — lib/planner/roi.tsReport a problem of a 2-car garage's design-day heat loss on BayHeat's standard worked example; a reflective kit cuts about 13 %CComputed by our engineinsulateFirst() 'door_kit_reflective' measure — lib/planner/roi.tsReport a problem. Either one barely moves the needle if the ceiling above the garage is still bare drywall — that's where most of the load is.

Savings vary. Find out why in the seller's fact sheet on R-values. Higher R-values mean greater insulating power.

EPS versus reflective, on the same door

Both kit types glue or clip into the back of a standard steel door's panels. An EPS (rigid foam) kit is thicker and typically in the R-6 to R-8 class; a reflective kit is a thin foil-faced foam layer that relies on a radiant air gap rather than bulk insulation, and manufacturers publish it in a lower R-value class than an equivalent-thickness EPS kit. Exact R-value depends on the specific kit — check the manufacturer's own fact sheet before comparing two products on that number alone.

Both figures beat the reflective kit's payback window on electric heat — an EPS kit pays back in about 0.2 yrCComputed by our engineinsulateFirst() 'door_kit_eps' — cost / savingsPerYear.electricReport a problem year, a reflective kit in about 0.2 yrCComputed by our engineinsulateFirst() 'door_kit_reflective' — cost / savingsPerYear.electricReport a problem year. The EPS kit removes more heat loss for a bit more money; the reflective kit is cheaper and lighter to install. Neither is the wrong buy — they trade off cost against the size of the cut.

Do the ceiling first

On the standard worked example, the door kit alone drops the design load from about 31,900 BTU/hCComputed by our engineheatLossDesign() on EXAMPLE_A_INPUT, bare ceilingReport a problem to 26,700 BTU/hCComputed by our engineheatLossDesign() with doorTypes: kit_eps_or_batt, ceiling still bareReport a problem — real progress, but the ceiling above an uninsulated attic is still the single biggest hole in the envelope, door kit or not. Bringing that same ceiling to R-30 on top of the door kit drops the load further, to about 17,000 BTU/hCComputed by our engineheatLossDesign() with doorTypes: kit_eps_or_batt, ceilingIns: R30Report a problem — roughly double the door kit's own cut, for one more afternoon of work. A kit on a bare-ceiling garage is still worth doing, but it isn't the whole job. See how to insulate a garage in the order that pays back → for the ceiling step and why it goes first.

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Buy a kit

What not to buy

Don't buy a door kit as your first insulation project if the ceiling above the garage is still bare drywall or open joists. The ceiling carries more of a typical detached or attached garage's load than the door does, so a kit bought first is money spent on the smaller problem — seal the door (see the weather-stripping page) and insulate the ceiling before spending on a door kit, not after.