Large vent blowing cold air

jagdipa

I have a large vent in the corner of my house (the side that the neighbour is) that is constantly blowing cold air in. I can't understand why its there, why it is so big, and why its not been build to stop such cold drafts. Does anyone know why the house was built with this, and would it be safe to block it up (either permanently with bricks, or temporarily with some insulation/old towels)?
Here's some images - the phone is to show the scale.

jagdipa

Sorry - one more photo. This is the outside of the vent

Martin_the_Unjust

What type of heating do you have in the room that the vent is in?

jagdipa

There is a log fire that was there when we purchased the house. We have been advised never to turn that fire on!

There is also a central heating radiator.

Alanp

It might be the ventilation requirements for your fire or a long defunct gas appliance 

tacpot12

The vent was installed because there is a log fire. It is a requirement of the UK Building Regulations. If the log fire remains, the ventilation must remain open. If you remove the log fire and cap the chimney (with a ventilated cap), you can fill the vent.
If you cap the chimney with a cap that is ventilated, you will get condensation inside the chimney and damp in the walls as a result. It only needs a little ventilation to avoid this, so you shouldn't worry that capping the chimney will give you draughts from the chimney. 

grumbler

tacpot12 said:

 If you remove the log fire and cap the chimney (with a ventilated cap), you can fill the vent.

Meanwhile why not just block the vent from outside (and from inside?) if you don't use the fire?

stragglebod

Don't block the vent without removing the fire first.

neilmcl

jagdipa said:

There is a log fire that was there when we purchased the house. We have been advised never to turn that fire on!

There is also a central heating radiator.

When you say "never to turn that fire on", does that imply that it's actually a gas, log effect fire? In which case this is exactly why that vent is there.

Your pictures are showing two different things, The first is an air brick, which you don't really want to block up, the rest of the pics relate to that vent of yours, which you shouldn't block up whilst that fire is in place.

jagdipa

Just to be clear, I don't use the log fire, I never have used the log fire in the 2 years I have been in this house, and I was advised by someone with a hetas badge to never use it until it's checked (he said the chimney was not correct). 

I do plan to replace it with a gas fire, but that will not be for at least 5 years.
So I'm guessing it would be okay for me to block up the hole. I was thinking of using some polystyrene and foil at first, and then maybe brick it up next summer.

EssexExile

It may be against rules to block it up with the fire still there (even if you don't use it) so I wouldn't do a permanent job, I'd do something that can be easily removed if necessary. I've just stuffed some insulation in mine.