In an ideal passive solar world, homes would be built as a long string of single rooms, so that every room would be heated by the sun and there would be no need to transport warmth from warmer to cooler rooms. In practical terms, long houses are rarely appropriate: traffic flow inside such buildings is often difficult and housing lots in towns and cities tend to be square or rectangular, rather than extended oblongs.

The best solution is often to build a square or rectangular design in which the most commonly-used rooms face the sun. Other rooms, such as storage and utility spaces, pantries, laundries, workshops and corridors are placed on the other side. The cooler rooms are heated by heat travelling by convection from the sunny side of the house.

There are also non-traditional layout options available: an open plan approach, for example, can work wonders in small buildings. Open spaces make buildings seems larger than they are, which adds to the feeling of freedom and space; it also means we can live in smaller homes which cost less to build, use passive solar energy more efficiently and have a smaller overall impact on the environment.

Open plan designs do have a price, though. Since they consist of one or two large, open spaces, they are extremely difficult to zone heat: as soon as passive heating from the sun stops, the cost of actively heating the space can be significantly higher than in a traditional home with multiple small rooms. There's also the noise issue, as fewer rooms mean less separation. In an active family with children, that can be a problem.

Is it possible to have too much sun?

Passive solar heating relies on gathering as much sunlight as possible. Or does it? Is it possible to have too much sunlight in the home?

The answer to that question is definitely "yes" – too much sunlight can be a problem. While it's true that the more sunlight there is, the more heating there is, you cannot ignore the glare caused by maximizing passive solar gain. It's rarely an issue, but some locations and house designs allow so much light into the living spaces that the home owners have to wear sunglasses indoors!

Thankfully, there is an intelligent solution to this problem. Careful placement of barriers, dividing walls, planters, interior stairwells, small entry rooms, masonry heaters and other obstructions – ideally those which consist of efficient thermal mass – can gather the sun's energy while blocking, reflecting or redistributing excess sunlight so that the space remains comfortable. Trombe walls and clerestory windows are particularly efficient for this task.