A fireplace is a lovely feature in a room and in the UK alone there are around 12 million homes with an open fireplace. We all know that burning wood adds to the country’s carbon emissions and we’re encouraged to burn less and to use Defra approved fuels if we do fancy a fire on a winter’s evening.
So, if we are all encouraged to use our chimney’s less - or ideally not at all - should we still be concerned about the impact our fireplace has on the environment? The answer is YES. We asked Sally Phillips, 100Green customer and founder of Chimney Sheep Ltd, to explain more.
Why is an open fireplace still bad for the environment when it’s not being used?
Having an open chimney is like leaving a window open all the time.
A chimney is cleverly designed to draw air out of a building all the time. It doesn’t just start working when the fire is lit. Even if we don’t use our open fireplace, most of us keep it as a feature.
But a report by the Building Research Establishment found that 80 cubic metres of air flow up the chimney per hour. So, if you have the central heating on, that’s a whole roomful of expensive warm air up the chimney gone in an hour!
How does so much heat get wasted through a chimney?
The warm air flowing up the chimney needs to be replaced, so cold air from outside is sucked in through gaps around doors and windows, and all other leaky parts of the building fabric. Even directly through walls, sometimes!
This syphon phenomenon is called the stack effect. The taller the chimney, the warmer it is inside and the colder it is outside, the greater the airflow. We don’t necessarily feel the warm air going up the chimney but if you have an open fireplace, put your hand in and you will feel a strong current of air.
How did you realise that heat escaping through chimneys was such a big problem?
I became aware of this phenomenon 14 years ago, when I moved into a terraced Victorian home in Cockermouth. It was a freezing cold winter when I moved in and I went round the house blocking all the gaps I could find. I was doing some renovation work, so I uncovered a bedroom fireplace to make it a nice feature. I quickly realized what a mistake that was!
I have always been concerned about environmental issues and when I discovered how much heat is being wasted up chimneys, I set my mind to what I could do about it.
Sally with a Chimney Sheep
How can we stop heat being wasted in our homes?
We all notice the cold draughts that come in through gaps – especially in older houses - and we go to a lot of effort to block these gaps, when really the simplest thing is to block the chimney.
Living in an area full of sheep, I was aware of the insulating properties of wool, and developed the Chimney Sheep®. It comprises a double layer of wool on a handle. It bungs the chimney and effectively cuts off that syphon effect.
A Chimney Sheep
The Chimney Sheep® is available in 12 different sizes to fit a range of fireplaces. It is made of coarse Herdwick wool which is wiry and gives the product the rigidity it needs to hold itself in place. The wool is naturally breathable so it permits a trickle of airflow through for ventilation and prevents mould or condensation.
Herdwick Sheep
So how much heat can one Chimney Sheep save?
The University of Liverpool. calculated that a Chimney Sheep saves the average home £150 a year off the heating bill. If every single chimney in the UK was fitted with a chimney draught excluder (or capped off permanently), the UK could save 2,760,000 tons of CO2 and £1,800,000,000 every single year!
Sometimes I think I’ve made a mistake with a 0 when I put that figure down but that’s correct. £150 x 12 million = one billion, eight hundred million pounds.
Can I still use my chimney if I have a Chimney Sheep?
Yes absolutely. It is easy to insert, and removable if you ever want to light the fire. It is fire retardant but comes with a little reminder tag, so you remember to take it out before lighting the fire.
I have an open fireplace and want to stop heat escaping. What can I do?
Chimney Sheep Ltd and 100Green have teamed up to bring 100Green customers a discount to help make savings on their energy bills. Use the code GREEN20 for 20% off a Chimney Sheep® chimney draught excluder*. Click the banner below to view the products.
*Offer can be used against all Chimney Sheep® chimney draught excluders. Valid until 31st December 2024.