What to do with the remnants of old hot air heating system?

[LoriT71]

I bought a house last August that currently has standard gas central heating radiators. However, the house used to have old-style hot air heating (it's a Wimpey No-Fines Concrete house from the 70s). All of the vents in the rooms have been removed and plastered over. However, in the cupboard on the upstairs landing there is a large metal (aluminium maybe?) chimney-type-thing that comes up out of the floorboards from downstairs (where the boiler used to be) and rises up into the ceiling of the cupboard, up through the loft, and out through a gap in the roof.

I'm not sure why this wasn't removed at the same time the heating was updated. But it's really drawing cold into the house (well, drawing heat out of the house I suppose). When I touch the chimney/duct/vent pipe in the cupboard it feels very cold. Initially I was going to wrap some insulation round it and hope for the best. But there are so many small gaps - like around the hole going through the ceiling into the loft - and the hole in the floor of the upstairs cupboard where the pipe/chimney/whatever disappears into the floor - not to mention the gap in the apex of the roof where the chimney/duct/thingy exits. So I might just be wasting money and effort with insulation?

Should I be trying instead to get the chimney removed? And if so, what kind of price should I expect to pay to get it done? I'm not averse to a bit of DIY. But I think this might be extremely out of my skillset. Plus I doubt I'd have the right tools for the job.

If anyone has an additional solutions I'd be really greatful. To give some context to my concerns - since moving in I've had a new combi boiler installed, along with new UPVC front door, back door and french doors in the living room. The existing UPVC windows are only about 6 years old. So you'd think the house would be able to retain heat fairly well. However, if I switch the heating off overnight at the moment, the house temperature can drop to 12 degrees over the next 15 hours (from approx 19 degrees with the heating on). So I obviously want to find out where the heat is escaping from.

Any advice gratefully accepted.

Lori
x

 

[jeff the gasman]

Just get a couple of quotes, these are usually free and the choice is yours then.

 

[simond]

Assuming it is not being used to ventilate a cupboard (compartment) with your new boiler inside, and there are no gas fires - the old flue is acting as a passive vent, so to start with, simply block it up at the bottom with some pillows, or screwed up newsprint in a bin bag.

Then you will get an idea whether it is worth removing.

A concrete house does not sound like the last word in insulation (concrete is a poor insulator) so I would be surprised if your house was particularly good at retaining heat inside. In other words, you may be looking at the wrong cause.

 

[LoriT71]

Thank you both for your replies. If I went ahead with getting quotes for removal, which category of tradesman should I approach? Plumber? Heating Engineer? Roofer?

The flue is definitely not being used for any venting purposes. The combi boiler is located in a boxroom in another part of the house, nowhere near the flue. So I don't need to worry about that. The problem with what you suggested about temporarily stuffing some pillows etc inside is that I am not able to get access to the inside of the flue at all. The bottom of the part that still remains goes below the floorboards in the upstairs landing cupboard (but does not come through the ceiling in the room below - so I'm assuming the open end is located within this space between floors). And the flue is totally sealed all the up through the ceiling in the cupboard into the loft. So I'm not sure how I could stuff anything inside it?

You're right about concrete not being ideal at keeping the heat in. This particular build is not solid concrete though - there are small spaces between the chunks of concrete because no fine aggregate was used in the mix. I guess the theory is that the small pockets of air will act as an insulator. I will eventually get external insulation added to the house, but for now that's a bit out of my budget.

Lori
x

 

[jeff the gasman]

A general handyman should cope with removal.
See if one of your friends or neighbours could recommend a good one.
Good luck.

 

[Agile]

Unless you want the space it occupies then all you need to do is to block it up as suggested.

It sounds more like a combustion air duct. You can block it either in the loft or downstairs.

May need cutting up with an angle grinder.

Insulating the house is unlikely to be cost effective with external media. Its usually done on council properties where spending can be more profligate.

But there may be local grants. Look round and speak to any neighbours where it has been done.

Tony