When a cool room door seal is done
How do I tell whether my cool room door seals need replacing? Does it really matter?
Published 21/09/2026. Written by the Pristine Cooling team, Kalgoorlie.
Two tests, both under a minute, no tools. Shut the door on a sheet of paper then pull it out: if it slides free, the seal is not gripping at that point. Then shut yourself in with a torch off and look for daylight around the frame. Yes it matters, quite a lot more than people expect, because a cool room fighting a leak never stops running.
Here is what to look for, then what to do about it.
The paper test
Take an ordinary sheet of paper. Close the door on it so half is inside, half is out. Pull.
You want resistance. A seal doing its job holds that paper firmly enough that you feel it drag. If it slides out like nothing is there, the seal is not compressing against the frame at that spot.
Do it every 300 millimetres or so, all the way round, including the bottom. A seal rarely fails evenly. Most of the time you find one stretch that has gone while the rest is fine, which tells you something about what caused it.
The torch test
Stand inside the room with the door shut. Turn the light off. Give your eyes a moment.
Any daylight you can see is air you are paying to cool. A thin bright line along one edge, a glow at a corner, light under the bottom sweep. If the room has no internal light switch, do it in reverse: torch inside on the floor, door closed, look from outside in a darkened room.
What a tired seal actually does
It is not just a draught. A cool room with a leak is a cool room that never reaches its setpoint, so the system runs constantly rather than cycling.
That does three things. It runs the compressor far more hours than it was costed for, which brings its replacement forward. It puts a constant stream of warm moist air onto the evaporator, so the coil ices up, which chokes airflow, which makes everything worse. And it makes your temperature record look bumpy, which matters the day somebody asks about it.
You will often see the evidence before you look at the seal. Frost forming on the outside of the door panel or on the frame means warm moist air is meeting cold metal somewhere it should not be. Condensation running down the outside is the same message.
Why they fail
Heat hardens them. Rubber that was soft when it went in goes stiff, then stops springing back when the door closes. In a Kalgoorlie kitchen that happens faster than the manufacturer had in mind.
Pallet jacks and trolleys tear them. A seal with a chunk missing at knee height has usually met a load of stock coming through at speed.
Doors drop. Hinges wear, the door sags a few millimetres, then it only compresses the seal along the top while the bottom hangs loose. This one looks exactly like a seal problem when it is actually a hinge problem.
Cleaning chemicals perish them. Strong degreaser on a rubber seal, week after week, shortens its life considerably.
The seal, against the door
Worth knowing before you order anything: a lot of the time the seal is fine.
If the paper grips at the top of the door but not the bottom, that is a door sitting crooked rather than a seal that has failed. Hinge adjustment, latch adjustment, sometimes a hinge replacement. Cheaper, quicker, then the existing seal goes back to working.
If the paper slides out everywhere, evenly, the seal has hardened all over and it has reached the end of its life. That is a replacement.
If there is visible damage, a tear, a section pulled out of its channel, a corner that will not sit flat, it is a replacement whatever the paper says.
The bit that gets missed
The bottom. Everyone checks the sides because they are at eye level.
The sweep along the base of the door takes every trolley wheel, every mop, every bit of grit walked in. It also sits where the coldest air in the room wants to fall out. A room with a perfect seal on three sides is still losing air if the bottom is worn through.
Same for strip curtains if the room has them. Cut short, pushed permanently aside or missing three strips out of twelve, they stop being a barrier.
What to do next
Run the paper test this week. It takes a minute per door. If it grips all the way round, you have nothing to do.
If it does not, the next question is whether the door hangs straight, which is worth having someone look at rather than guessing. Seals get replaced on a scheduled visit rather than as an emergency, which is one of the ordinary things a maintenance visit picks up before it becomes a call at 11pm.
If a room is already struggling to hold temperature, that is a different conversation. Our after hours line is for commercial sites. You do not need an account with us to ring it. The terms are on the 24/7 Breakdown and Repairs page.
More on the rooms themselves is on the commercial refrigeration page.
Ring us and we'll tell you when we can be there
Same number either way. Ring it if something is down right now or if you want a quote, a service or a maintenance contract set up.