If you live in a rented flat or an older, protected building, you'll know the particular frustration of a draughty chimney. You can feel exactly where the cold is coming from; you know a permanent fix would sort it — and yet a permanent fix is the one thing you're not really allowed to do. Your landlord would rather you didn't start altering the fireplace, or your home is listed and the fabric of that lovely original hearth is protected for good reason.
The good news is that you don't need to touch a single brick to stop the draught. In fact, the best solution for both of these situations is the one that leaves no trace at all.
Why the usual fixes aren't an option
When we talk about permanently sealing a disused chimney, we usually mean fitting a register plate, capping the pot at the top, or building the opening up entirely. These are all excellent, long-lasting measures — but they share one problem for renters and heritage homeowners alike: they're permanent, and they change the building.
For a tenant, that almost always means asking the landlord, and most tenancy agreements quite reasonably forbid you from making structural alterations. Fitting a cap or a register plate is exactly the sort of thing you'd need written permission for, and you certainly can't take it with you when you move.
For anyone in a listed building or a conservation area, the picture is more delicate still. The whole principle of caring for a historic building is that changes should be reversible wherever possible, so that nothing of the original fabric is lost. Historic England's own guidance on open fires, chimneys and flues encourages homeowners to address draughts and heat loss — but to do so sympathetically. A permanent seal on a historic flue can trap moisture, hide problems, and remove a feature that a future owner might want to bring back to life. Several local councils, including a number here in the North of England, specifically list a removable chimney draught excluder as a recommended, low-impact measure for exactly this reason.
So the question isn't really whether you can draught-proof your chimney. It's how you do it without making a permanent change.
The case for a reversible, invisible solution
This is where a Chimney Balloon® comes into its own. It's inflated in place inside the flue, out of sight above the fireplace opening, and it holds itself there by gently pushing against the walls of the chimney. When you want it gone, you simply deflate it and lift it out. There are no fixings, no plates, no plaster, no marks — nothing to explain to a landlord and nothing to undo before you hand the keys back.
That reversibility is the heart of it. Because a Chimney Balloon® makes no permanent change to your fireplace, it sidesteps almost all of the difficulties that come with rented and protected homes:
- Nothing is fixed to the building. No screws, no adhesive, no register plate — so there's nothing that counts as an alteration.
- It's completely invisible. The balloon sits up inside the flue, so the appearance of your fireplace is entirely unchanged. For a listed interior, where the look of the hearth is part of what's protected, that matters enormously.
- It's fully removable. Take it out in an afternoon, and the chimney is exactly as you found it. Perfect if you're renting, and perfectly in keeping with the "reversible changes only" principle that governs work to listed buildings.
- It goes with you. Move house, and your draught-proofing comes too.
And it works. According to the Energy Saving Trust, blocking an open chimney can save you in the region of £65 a year, per chimney — a meaningful dent in your heating bills for a device that costs less than a takeaway. You can read more about exactly how that saving happens in our piece on the stack effect, the clever bit of physics that permanently syphons warm air out of your home all day long.
Renting? You almost certainly don't need permission
We're not solicitors, and every tenancy agreement is different, so do have a quick read of yours. But as a rule of thumb, a device that simply sits inside the flue and lifts straight back out isn't an alteration to the property in the way that a fixed plate or a capped pot would be. You're not changing anything — you're temporarily filling a gap, the same way you might pop a draught excluder along the bottom of a door. It's one of the most effective energy-saving measures a tenant can take entirely on their own.
Listed buildings and conservation areas: keeping it sympathetic
If your home is listed, the guiding word is reversible. A Chimney Balloon® is about as reversible as a measure can be. That said, two things are worth keeping in mind.
First, ventilation. Historic buildings were designed to breathe, and a completely sealed flue can lead to damp and condensation. This is something we designed for: every Chimney Balloon® has a small vent in the side that lets the chimney keep breathing gently, which helps keep moisture at bay. We've written about this in detail in does the Chimney Balloon cause damp? — well worth a read if your home is old and prone to a bit of damp.
Second, when in doubt, ask. If you're planning anything permanent, or you're simply unsure what your listing allows, a quick conversation with your local authority's conservation officer is never wasted. For a removable balloon, though, you're on very safe ground — it changes nothing.
A quick and important safety note for any home, old or new: never block a flue that serves a working gas appliance.
Getting it right
Fitting one takes a few minutes and no tools at all. The only thing to get right is the size, and that's simply a matter of measuring your flue — our measuring and fitting guide walks you through it. Choose the size that matches your flue opening, inflate it in place, and leave the little tab hanging down so it's easy to find and remove when you'd like your chimney back.
If your fireplace is one you relight from time to time — say a solid-fuel opening you use on the coldest evenings — you might also look at our sister product, the wool Chimney Sheep®, which is designed to be popped in and out around regular fires. But for a chimney that's sitting unused and quietly costing you money, a Chimney Balloon® is the neatest, most reversible answer there is — whoever owns the walls around it.