Frequently Asked Questions about Fireplaces

If you can't find the answer to your question here please telephone us on 021 979 4567.


1. How hot can I run my stove?

 Over firing your stove will damage the internal components and will also invalidate your warranty. We can supply a Charnwood flue pipe thermometer: a simple device that attaches to the flue pipe of your stove. This tells you whether you are over-firing or under-firing your stove and you can adjust the burning rate accordingly.


2. Can I heat radiators, under-floor heating, pools or domestic hot water from a stove?

We supply a number of boiler stoves that can heat domestic hot water and up to approximately 10 radiators or other alternatives such as Jacuzzis, pools or under-floor heating. For many of our models we also offer add-in boilers and flue boilers for heating domestic hot water and/or radiators.


3. Do I need to burn seasoned wood on my stove?

To get the best from your fireplace and to ensure a long life-span of trouble free heating – Yes (preferably). Wood should be cut, split and left to season in a dry, well-ventilated area for at least one year in damp climates (you may find that wood is quite well seasoned after 6-9 months in our hotter/dryer climate). You can generally tell if a log is dry because the bark will come away easily in the hand and the log will have splits across the grain. 


4. Does my chimney need lining?

If you find that your chimney is in poor condition then expert advice from your stove installer should be sought on the necessity of having it lined. If it is necessary to line the chimney then a lining suitable for solid fuel must be used. Alternatively, you can obtain a flue kit sufficient for the length of the chimney which we can supply for you.


5. What size stove do I need?

This is a question that you will find answered differently by nearly every fireplace supplier you speak to. We like to err on the side of caution and would suggest the following tips.

All closed combustion stoves carry a Killowatt rating. We calculate how much area can be heated by applying a formula which has been common for a considerable number of years throughout the fireplace industry. The formula varies around the globe dependant on local climate and insulation in the home but it gives you a good idea on which to base your assessment :

"Cubic volume of room (m3) divided by 25  = killowatt rating of stove needed to heat the room".

Please bear in mind that these calculations are very subjective as you should factor in the insulation in the room, number of windows, outside temperature etc, etc. Some suppliers will divide by a factor of '30' and others by '20'. However, this calculation will give you a 'ball park' figure to aim for when assessing what stove you need for your room.

It is also worth noting, regarding our Charnwood range of appliances, that these fireplaces are rated in accordance with UK weather conditions (rated at an outside temperature of -1° C).


6. Do I need ventilation in the room that the stove will be in?

Stoves with a heat output of over 5KW ideally require additional ventilation. This can be supplied via a permanent vent to the room. Some of our models offer the option to duct combustion air directly into the appliance.


7. Where can I find my closest Charnwood and Invincible dealer?

We supply throughout South Africa in all the major cities and Provinces – Cape Town, Johannesburg, Durban, Pretoria, Kimberley, Nelspruit, Polokwane, Bloemfontein, Bhisho, Port Elizabeth, Rustenburg, Eastern Cape, Free State, Gauteng, KwaZulu-Natal, Limpopo, Mpumalanga, North West, Northern Cape, Western Cape. We are also willing to help you even if you are not in any of these area's as we will delivery anywhere in South Africa. Call us and we will assist you as much as we can.


8. What type of flue should I use?

There are three main types of flue in use throughout the South African market:

  • Galvanised Steel
  • Grade 430 Stainless Steel
  • Grade 304 Stainless Steel

Galvanised is the least resistant to corrosion and we do not recommend it for use directly in contact with your fireplace (i.e for the first length of the flue on top of your unit). It will also give only limited lifespan in the exposed elements. With these considerations in mind, a galvanised flue may be used as a chimney 'liner' within an existing brick built chimney.

Grade 430 Stainless Steel is our best seller. It offers a good level of durability at a very reasonable price level so we consider it to be good value for money. We would not, however, recommend it's use in coastal areas where high levels of salt and moisture will attack the Chromium oxide coating which protects the steel from corrosion.

Grade 304 Stainless Steel is the most common stainless steel used throughout all types of industries and is generally suitable for all locations throughout South Africa. It can cost between 45% and 55% more than Grade 430 but you will more than recoup your money back in terms of it's extended lifespan.

There are even more durable grades available (316 is a marine grade stainless steel and is particularly hardy in very high salt environments). We cannot guarantee how long a flue will last as each installation is unique but, as a rough guide, we have had Grade 430 installations (in land) that are still performing well after 10 years.


9. Why is my fireplace smoking?

  • One simple cause of this problem can be wet fuel. Wood should be seasoned (or stored in dry conditions) to reduce the moisture content before burning. Please see question 3 above.
  • If a fireplace spills smoke into the house only on windy days, the problem is downdraft, possibly resulting from a chimney that is too-short or environmental conditions beyond your control (especially if you live in the windy Cape). Consider extending the chimney or installing a wind-deflecting chimney cowl (if not fitted already) or fan. Chimneys should ideally be at least as high as the tallest part of your roof or the tallest structure within 3 metres of your chimney (so look out for trees and other buildings in close proximity to your chimney).
  • Flow reversals typically occur when the operation of exhaust fans, including those for clothes dryers, causes negative pressure in a tightly closed house. Either open a window or purchase a unit that has an air-intake option which is a pipe that has the sole function of supplying your fireplace with fresh air. A leaky attic in a multi-story house (not too much of an issue here in South Africa) can even create a chimney effect and cause chronic depressurization. The solution in this scenario is to seal all openings between the living space and the attic.
  • Install a decent cowl. Consult a fireplace professional who can install a wind-diverting chimney cowl. We supply the Cyclone cowl which we find proves effective in all weather conditions. Although the installation itself is relatively simple, working safely at a chimney top isn't, and some suppliers will only sell products to professionals.
  • Install a chimney fan or “braai buddy”. Depending on the type of chimney you have, you may be able to install these fans which effectively 'suck' the smoke and gases up your chimney.The demanding conditions these fans must endure, such as extreme heat and corrosive flue gases, may make them seem a bit costly but do your research, find the right product and they are guaranteed to solve the problem.


10. Why is Charnwood so much more expensive and what are the differences between Charnwood and Invincible?


We get asked this a lot!

First of all – BOTH ranges are great products! Charnwood carry a 10 year (limited) guarantee and so do the Invincible Cast Iron stoves. The Invincible Plate Steel stoves carry a 5 year (limited) guarantee. Both ranges are certified to meet ‘CE’ standards which means they qualify to be sold in Europe. Both do basically the same job. Both have been sold in South Africa for over 10 years.


  • Charnwood is manufactured entirely in the UK using components and raw materials manufactured in the UK (except the glass which is Schott Robax from Germany). Invincible is a robust product manufactured in China (also with Schott Robax glass).


  • The nature of a closed combustion system means that the better the air-seal on the unit the better control you have on your fire and the more efficiently it will operate. Charnwood fireboxes are manufactured from one piece of boiler plate steel ‘wrapped around’ to create the sides and the two other plates are welded top and bottom. The doors are cast iron. This creates a very good seal on the stove. Invincible cast iron stoves are a traditional cast iron manufactured product. This means that they are made up of 6 plates, bolted together and sealed with a high heat putty/cement to make the firebox as air-tight as possible. This is the same process in the traditional ‘Dover’ stoves that you may be familiar with. The Invincible plate steel fireplaces follow a similar pattern to the Charnwood manufacturing process but use a thinner steel (4mm for the firebox compared to 5mm).


  • Boiler plate steel (Charnwood) heats up quicker – bonus. Cast Iron (Invincible and Charnwood) retains heat longer – bonus. Charnwood use a mixture to get the best of both worlds so to speak.


  • The patented Charnwood ‘quattro-flow’ air control system means that you have a very simple mechanism to control your fire as opposed to various ‘vents’ which you use on the Invincible range.  This makes it an easy ‘learning curve’ for the user. 


  • The Charnwood ‘riddle’ mechanism is second to none for burning a mix of solid fuels (e.g wood, anthracite or coal). The Invincible range has some models that incorporate a riddle mechanism but is primarily designed to be a wood-burning stove.


  • The Charnwood boiler plate steel method of construction means simpler lines for those who like a more contemporary (modern) looking fireplace.


  • Charnwood fireplaces are available in up to 8 colours (charge of R1,750.00 extra). Invincible are available in black (with some models offering coloured side panels).




The best way to see the difference is to check the touch and feel of the units yourself which are all displayed in our showroom!


the fireplace company