As the name suggests these fires generally require a hole which can accommodate the dimensions (width, height and depth of the inset body of the fire) much the same as say an oven housing in a kitchen. Basically a tall cupboard unit that the depth of the oven fits into allowing for a flush appearance of the frame.
If the property has a chimney breast as found generally in older properties and suitable for a solid fuel fire, then the brickwork can be opened up to the desired dimensions at whatever height from the floor. A reinforced concrete lintel inserted above the top of the opening and bricked up from the floor to the required height. This new brickwork can then be plastered and decorated. Behind the brickwork should then be infilled to form a floor for the fire to sit on and be fully supported.
Because the chimney breast was built to extract smoke through to the chimney pot, there will be a ‘draw’ of air from the room. To eliminate this, a plastic bin liner partially filled with crumpled newspaper then tied to resemble a balloon can be pushed up into the flue opening. This will also serve the purpose of preventing any soot deposits etc., falling onto the fire from above. It’s also advisable to have a rain cowl fitted to the chimney pot to avoid rain water ingress into the chimney.
The electric fire will then heat and convect the air sourced from the room when the heater is in use. This results in the electric fire having a 100% efficiency rating as no heat is lost, as opposed to an open flued appliance.
As many modern homes do not have a chimney breast, this does not mean that an inset fire cannot be accommodated with relatively modest cost and disruption. As with the oven housing, a mock chimney breast can be easily constructed by means of some simple D.I.Y joinery.
Firstly, the depth of the mock breast only needs to be as deep as the inset body of the fire. For example the popular Flamerite Corello electric fire only requires 125mm/(5″) inset depth and even the deepest of their models the Flamerite Landscape only requires 160mm/(6.3″).
The overall width of the mock breast can be any desired width after the overall width of the fire is accommodated. Thus having a minimal loss of space within the room, but providing a stunning feature focal point.
The frame (studwork) I would suggest is best made from 3″ x 2″ timbers with plasterboards then nailed to the frame. The studwork construction is very similar to that of constructing a wall partition, but without the need for sound insulation. This method is quick to construct, lightweight and does not require specialist building skills. There are many articles available for this kind of project online, or from D.I.Y. stores. In essence this will be a shallow three sided floor to ceiling housing unit.
Once the opening height and width has been decided, a frame cross member can be fixed and a corresponding batten to the wall you are building off from. A piece of plywood or similar board can then be cut to size to provide a floor for the fire. Ensure that there is a batten or wooden noggin provided where the fire needs to be screwed up against. A suitable electric socket can be located at a convenient point within the void of the breast, but not directly behind where the fire will sit. A competent electrician will be able to advise regarding this aspect. This conceals and avoids any unsightly trailing of the fires electric supply cable.