How much cold air do you think comes down a chimney?

[Trumpelina]

Our original lounge is now a bedroom with a full open (unused) fireplace in it. We closed the opening with clingfilm to keep spiders out but despite central heating this is the coldest room in the house. It has one outside wall and bare floorboards with the gaps between sealed up & double glazing. How much do you think the presence of the chimney is responsible for it being a cold room? For reference it's a large 30s house. To the side of this room is an enormous open hallway which is draft city but the lounge/bedroom does have draft excluder fitted all around the door.

yes chimney sucks cold air in. Cling film won't block it.

I think the hot goes up rather than the cold coming down. Stick a few old cushions or pillows/duvet up there. The 'enormous open hallway' is probably providing a good source of cool air, and the bare floorboards are also contributing. Get some rugs and/or carpet.

We blocked our chimney with a balloon thing we got on amazon and the difference in temperature was incredible.

Anybody know what would be a good/cheap way to close it temporarily? Would a stout piece of cardboard duck-taped in place be enough to keep the drafts out?

We’ve got cushions shoved up our chimney. It’s much colder in the sitting room when we take them out.

When we don’t use our open fire we stuff a pillow in a plastic bag in it. Loads of cold air comes through, otherwise. If you don’t intend to light a fire put a piece of hardboard in the opening.

just buy one of these for £9

Or light the fire to keep it warm...

if you've sealed it with clingfilm, probably none.

If you hadn't sealed it with clingfilm, probably none, because warm air goes up a chimney and is replaced with cold air via draughts.

Bare floorboards and one external wall, you say? So are the other three walls internal? What is above the ceiling? Is there a bay window with a little roof?

Bare floorboards are bound to be cold.

What have you done to reduce draughts? How did you seal the gap under the skirting?

How many kWh of heating do you put into the room, and what are its dimensions?

Google chimney damper and sort that out if you haven't already. Do the cushion/air bag thing as well. I remember my mum sealing mine with cereal box cardboard and sellotape, and it wasn't brilliant.

old pillow in a bin liner, stuff up chimney. Remember not to light fire.

no need for Amazon.

Old dressing gown and pillows in a black bag stuffed up the chimney works just fine.

I will add to all
Those telling you to stuff pillows and duvets and the like up there.....you better bloody hope that chimney is properly capped or you going to have wet/damp mouldy clothing and bedding stuck in a chimney in a room you're sleeping in
Spend the £9 buy the inflatable chimney balloon and that's the draft taken care of.
However listen to PigletJohn ( voice of reason) and think about all the other causes of the room being cold and address those too

We have a chimney balloon in the dining room fireplace and it's made a huge difference

We have a piece of chipboard cut to the right size and then have it covered in a pretty fabric that goes with the room decor. Ours isn’t stapled on but I think you could.

There are chimney balloons in ours - they were there when we moved in. They work.

You need a Chimney Sheep

www.chimneysheep.co.uk/shop/

Mine makes a massive difference. It keeps the living room warm and also stops birds mess / soot etc. coming down the chimney.

Oooh thanks Piglet. The room is 15ft X 12ft with a bay window but no flat bay roof as there's another bay above. Yes one external wall and three internal. This room is surrounded by our (admittedly) bloody freezing hallway, a super-insulated kitchen behind & next doors semi to the other side. Above is another bedroom. All the gaps across the floor and skirting area have been wedged with cardboard and then filled with wood filler & painted over. The bedroom doorway has had draught excluder fitted all around. There is a 5ft x 2.5ft large double radiator on the back wall (far from the window). The ceiling's are 9ft high.
I know the hallway could benefit from some work but it isn't easy. It's 22ft X 9ft, has 5 leaded windows (one huge) & is 'open' up through 3 levels. Draughtwise it leaks like a sieve. There are 4 understairs cupboards that have doors fitted into frames that leak cold like mad but that's another thread.

I think I'll start by giving the chimney pillow a go, plus sealing it up with something better than clingfilm & see what difference that makes. If I have the money in future, I'll pull up the floor and lay celotex underneath.

Oops, just remeasured, it's 18x12ft

Are the chimney sheep really good Flying? We are renting a 1774 house without insulation abroad, and have two chimneys that could do with those. I h ave been eying them up for some time.

Aerogel is now available as floor boards, so you could insulate on top of the floor rather than under.

I've no idea what the price would be, though. More expensive than celotex and you might need to shave a few mm off doors and skirting boards, but on the other hand no need to take the floors up and a better thermal result.

www.aerogel.uk.com/floorboard.html

repeat - old pillow in a bin liner. reduce, reuse and do not piss away cash!

I've never heard of Chimney Sheep but have effectively made my own from a woollen insulation batt, with a dangle so I can't forget it.

We’ve got screwed up newspaper in our with a bin bag covering it. Glad the landlord bothered to sort that for us...