Hull and East Ridings Leading Chimney Sweeping and Stove Service Team
Chimney cowels
Why & When to Sweep
How a chimney works
Opening Up fireplace
Starting your fire
Different Fuels
Chimney cowels
Chimney Problems
Problems cont....

What type of chimney cowl should i have fitted.


IF UNSURE THEN TALK TO KEV !!!! If you require a cowl of any kind, we can source one for you - usually at  a very competitive price...

We also provide a fitting service if the apprentice is feeling ok about heights - go easy on him (hey ... at least I dont send him up the chimney anymore - he hurt his shoulder!!)


The information below includes

  • Redundant chimneys
  • Live chimneys
  • Anti downdraught




Redundant chimneys...

If you have a chimney in your property which you do not wish to use, ideally it should have a cowl suitable for that purpose fitted.

If a chimney is left open to the elements, both rain and birds can cause a major problem.
  • Rain can work its way down the chimney and bring old soot with it which can end up in your room if there is an open fire or it can run down the outside of a stove if fitted and cause it to rust which can make the stove look very unsightly along with thick black tar which it has collected on the way down and which will stain your fireplace.
    It is also a potential problem as it can eventually lead to holes forming in your
    wood/multi fuel stove - dangerous due to heat and, more importantly, fumes escaping into the room. It is also very expensive to put right...a new stove is much more expensive than having a cowl fitted and your chimney swept regularly!!
  • Birds can cause a problem when they nest in redundant chimneys. Many people have spent large sums of money on rendering and the stripping of walls to find a 'leak' which may only have been caused by rain 'leaching' through the sticks of a birds nest and into the chimney breast.
    This quite often happens in bedrooms where the chimneys are more often than not sealed up.


All chimneys which are not in use need to breathe or they will dry out and major damage can occur to both the inside and outside of the chimney and ultimately your property.

Save yourself a lot of heartache and expense and choose the correct cowl for both a 'live' chimney and also for a chimney which you are no longer going to use.
Have it fitted professionally or you will have wasted a lot of expense.

The following pictures show you the type of cowls which SHOULD NOT be used on 'live' chimneys. They allow ventilation only but do not allow sufficient fumes(ie Carbon Monoxide) and smoke to leave the chimney.

Allowing one of these to remain on or be fitted to a 'live' chimney could put your life at risk.




Live chimneys(chimney in use)


The following picture is the type of cowl which ACS (HULL) Ltd ly recommends - for 3 reasons.

  • The metal 'hat' keeps the rain out. Most important if the chimney is very straight
  • The mesh stops birds and debris.
  • Perhaps most importantly, the height of the mesh allows the chimney sweep to get brushes right up and out of the pot without disturbing the cowl. This means the brush can be 'jiggled' to dislodge any build up of soot on the mesh thereby keeping the airflow to a maximum.


The clamps on the OUTSIDE of the pot mean that when the chimney is swept,the brush will not push any 'legs' out from inside.
There is a junior version of this cowl also. However, there is very little room for the brush to come up and we highly recommend spending a few pounds more and purchasing the larger version.

A lot of cowls have metal legs which just push into the top of the pot.
These are not ideal from the sweeps point of view and are easily dislodged or knocked off completely. Not ideal for either the sweep or the client!

Want a cowl? We sell them too...



Anti downdraught

Anti downdraught cowls are for use where there are problems with the fire 'drawing' (getting enough air to suck the heat up the chimney thereby keeping the fire going).
There are several reasons why a fire or stove does not draw properly

  • The location of the property.
    Are you low lying?
    Are there trees close by?
    Is your property in amongst other tall buildings?
    All these outside influences can have an effect
  • Is it windy outside? Strong winds will quite often cause a change of direction and can create a temporary problem with the draw on the chimney.
  • The stove itself - is it fitted correctly?An ill fitting stove will affect the draw on it.
  • Is the correct cowl fitted? See the section above on Redundant chimneys. The wrong cowl could also have allowed birds to nest in the chimney. This WILL affect the draw!!
  • An open fire often opens into a large chimney and the draw on this will be significantly reduced. In any case, at least 60% of heat from an open fire is lost up the chimney.
  • Very cold weather will also affect the (initial) draw on a chimney. It is not unusual to get a blow back of smoke from both an open fire or a stove when lighting on a very cold day.
    It takes time for the chimney to heat up and warm the thermals which will draw the heat upwards.
    To help avoid a roomful of smoke, start with a small fire and allow the chimney to warm up slowly. Banking the fire up to begin with will almost certainly guarantee smoke!!
  • Finally - and importantly - has your chimney been swept?
    If it has - has it been swept properly?
    An unswept or badly swept chimney will undoubtedly cause you problems.
    Soot and creosote can build up inside the chimney. As it reaches the top of the chimney, it cools and this is where potential problems could be created. Any blockages are nearly always due to the build up of this residue and the only sure way to remove it is traditionally, with brushes.
    A long unswept chimney however, could have a build up of creosote (from wood) which has set like rock and cannot be removed by sweeping alone
    Burning a chimney cleaning log can help flake this so that when it is swept, the chimney sweep can remove most of it with brushes.

This is by no means an exhaustive list as to why a chimney does not draw properly. However, it may give you an idea where to start looking.

Here are some pictures of cowls sold as anti-downdraught...

Not to be used with an oil stove/boiler. The increased airflow could potentially damage the    stove                      


Stainless steel cowl suitable for use with Stainless Steel flue system



HomeContact UsAbout usPricingCode Of ConductOur termsSite registrationInsurance DownloadAll about chimneys
All Rights Reserved - acs (hull) ltd 2009