THE DILEMMA: Carol and her husband Peter recently bought a 1930s three-bedroom terraced house that has been “knocked through”, creating an open-plan layout on the ground floor, except for a small, galley-style kitchen with a serving hatch into the dining area. The previous owners added an extension to the ground floor but failed to give it any particular function.

Carol's dilemma is whether to knock the galley kitchen into the dining room, building a set of doors into the extension to create a second living room, or move the kitchen into the extension. Carol says the house is hard to heat, even though the back faces south and and has sun all day.

THE SOLUTION: Just as we smirk at the home improvement crimes of old - avocado bathroom suites and crazy paving, for example - so future generations will be bewildered by our Nineties/Noughties obsession with “open plan” and “extensions”. It seems we are desperate for space but are not entirely sure why. Many of the homes I filmed for Honey, I Ruined the House on Channel4 featured similar problems to Carol's: it's not that there's not enough room, it's that the room has no useful function.

The solution for Carol and Peter seems simple: the kitchen/dining space should be located at the back, so that when the adults are in the kitchen they can keep an eye on the children in the garden. As the rear is south-facing it also makes sense to locate spaces here that are used frequently. This means putting the kitchen in the extension, and possibly removing the division between the extension and the existing dining room to create a kitchen/dining/family room. The existing galley-style kitchen could then be incorporated, by removing the dividing wall, or converted into a utility room.

This leaves the issue of the living room which, if it is self-contained, should remain so, creating more of an adult refuge next door to the hurly-burly of the family room. When my husband and I bought our first home, a loft in the East End of London, I too fell for the open-plan mantra. He is a football fan and it was hell on match days because there was simply no escape from all the shouting at the TV. So I have learnt from bitter experience that separate rooms are really important.

If Carol and Peter decide to invest in works on this scale, which will inevitably require new flooring, they could tackle their heating problem by fitting an underfloor system, which will be more efficient. They could also add some insulation to the perimeter walls; a good architect will be able to advise in more detail, in tandem with local building control officials.

Finally, as Carol's home receives so much sunshine, she could fit a solar water heater. The Energy Saving Trust (energysavingtrust.org.uk) has plenty of useful information.

Do you have an inner dilemma? E-mail: property.consumer@thetimes.co.uk

Times recommends

• Interior design: It's time to end our craze for open-plan living
• How to make cool bedrooms for kids
• Inside Zaha Hadid's East London apartment