Can I simply replace a chimney stack with a low profile vent?

Kernel_Sanders

I'm having solar panels fitted right up to my chimney stack, so want to make it as low as possible to reduce shading. It's a small square one (2 bricks wide), originally built in the late 1970s for coal although it is currently topped off with an round aluminium grill. It carries the fumes from my old gas fire with back boiler, but the latter may become redundant when I have a condensing one fitted elsewhere. The stack is part way down the roof, so I'd prefer a flattish one that could be laid diagonally at the same angle as the pitch. Will I need to add/replace any of the liner, and what other aspects do I need to consider?

ormus

you should consider fitting the new condensing combi boiler first.
then you could do almost anything you like with the chimney stack.

bobthedambuilder

Here's a link to a webpage which describes the regs for minimum flue heights in various circumstances.
http://www.firesonline.co.uk/acatalog/Stove-Building-Regulations.html
I know it refers to stoves, but I would have thought you'd need the same for a gas or open fire. If the gas fire is disappearing and you're not replacing it with anything else, as ormus says, you can do what you like with the stack. Just remember that if you or someone else in the future decided to reinstall a fire or stove, rebuilding the stack would be a significant expense. Is the shadow from the stack a problem all day?

Kernel_Sanders

bobthedambuilder wrote: »

I know it refers to stoves, but I would have thought you'd need the same for a gas or open fire.

Surely the regs for a gas fire wouldn't be as strict as for those that produce smoke?

Canucklehead

Kernel_Sanders wrote: »

Surely the regs for a gas fire wouldn't be as strict as for those that produce smoke?

Advice is available here.

Canucklehead

bobthedambuilder

Kernel_Sanders wrote: »

Surely the regs for a gas fire wouldn't be as strict as for those that produce smoke?

If you click on the BReg link on the page I gave you, you can see all the provisions (it's quite a weighty pdf document). You are correct that the diagram on the webpage applies specifically to flues for solid fuel appliances, which would include woodburning and dual fuel stoves, open fires etc.

The real question is whether it is worth removing a functioning chimney and thereby taking away (or at least making more difficult) future options for heating inside the house. But that's your choice.

keystone

The design and construction of the chimney and the stack is as much to so with the "draw" for the fireplaces it supports as taking away fumes and smoke.

You will reduce the ventilation it provides by chopping the top off (by how much I have no idea). Bearing in mind that regulations have been tightening up and tightening up over the last few years regarding ventilation for open flued appliances (to the extent that rooms with appliances that have worked perfectly satisfactorily and safely for donkeys years suddenly have to have enormous holes bored in the wall to provide the ventilation that the current regs say is now required) you nneed on site advice. Get the guy in who services your gas appliances to give you some.

Cheers

PS In the grand scheme of things I dont feel a shadow from your chimney stack will actually make a great deal of difference to your power generation scheme. A cost-benefit analysis might be a good plan first.

rustyboy21

Another thing to take into account, is the resale value of your house , if you decide to take the chimney stack down.

Yes you may not need it in the future, but who can say that the next owners of the house wont? The amount of times I have people in my shop wanting,say a stove, but don't have a flue and then they get stroppy because of the added expense of either
1. twin wall lining
2.re instating chumney stacks.

Yes it may make your life easier nw, but if it could possibly knock a couple of grand off your house price in the future, was it worth it? New home owners have dreams of what they want to do with a prospective house, if your aim of a little bit more light to your panels, stops them doing, or deters them from going on with what they want to do in the future, you may have lost a valid sale.

As poster above says, is it worth it, for a chance oflosing out in the future.

Am I correct in saying solar panels don't actually need direct sunlight, do they only need actual daylight to work? If so, it isn't really going to make any difference really. Plus take into account, you will have to get the new boiler fitted now, as you wont be able to operate it with no chimney.

ed110220

I believe even a small amount of shading makes a big difference to output as you don't just lose the generation from the shaded area, you drag down the performance of the unshaded panels too. So you may find that an 11 panel unshaded system gives better results than a 12 panel system in which one panel is shaded.

I doubt many prospective buyers would even notice the presence/absence of a chimney - it's the sort of thing people only notice when they get the whim to put in a stove or whatever the current fad is, so I wouldn't worry about it.