Hi, here's a few things to consider when replacing a gas fire.

Condition of chimney:
Is the chimney in good or bad condition? As a gas safe engineer I am required to carry out a test using smoke bombs to determine if the chimney has the right amount of 'pull' to get rid of the fumes. Should this fail, you will need a new flue liner which could be costly and sometimes rather destructive. Should it pass on the other hand, all you need is the right fire to suit your requirements.

Builders opening:
Is the condition of the builders opening good or bad? This is the square hole if you like where the fire is positioned at the bottom of the chimney, this will require investigation prior to your new fire being installed for cracks and weaknesses where fumes could escape back into the room. If this fails it would need properly rectifying with fire cement and any weak spots testing. Should this be ok, again all you need is your new fire.

Ventilation:
Checks are required to ensure the room has adequate ventilation to support your fire. Should this be ok, again you would just need the new fire.

电气火灾:
If you opt for an electric fire, they certainly are not as warm as gas fires and would require your builders opening to have a vent in order to stop damp issues. In some cases depending on the gas engineer, you may require an electrician if there is no power nearby. They look really nice but aren't as warm.

Summary:
All in all, I would recommend a gas fire if its the heat you require not design (as you have stated) but, ensure you have a gas safe registered engineer with experience quote you for the works and talk you through these important steps. Your life could be at risk of carbon monoxide poisoning if you get the wrong engineer. Always ask for gas safe ID.

Hope this is helpful,

Regards,

Brett Grayson.
R&B Plumbing & Heating Services LTD.

As above it depends on what is found once the old fire is removed. I would ask someone to disconnect the old fire and then advise on you options once they have accessed the chimney.