Sunrooms differ from conservatories both in form and function. While a conservatory is usually fully glazed and mainly for use in the spring and summer, a sunroom usually features solid walls as well as glass and is intended for use all year round.
As sunroom design needs to factor in four-season comfort, and that means planning both heating and cooling systems. This can mean that a sunroom will be more expensive than conservatories, not just in terms of the building costs but also the year-round running costs.
So it pays to plan a sunroom carefully and make it as energy efficient as possible to ensure comfort, style and cost-efficiency in both summer and winter. Decisions on the amount of glass, floor material, heating and the impact on the rest of your home will affect the success of a sunroom project.
One of the first things to consider when designing a sunroom is its orientation. Most sunrooms are built facing south to capture as much of the summer sunshine as possible. South-facing sunrooms capture the most light and are more sheltered in poor weather.
But, if you intend to use a sunroom mostly in the morning or evening, then it's worth considering an east or west-facing sunroom. A south-facing sunroom can overheat on sunny summer days, need more solar protection and more doors and windows to allow cooling fresh air inside.
Energy efficiency becomes more of an issue if your sunroom uses lots of glass. Not only will it overheat in the summer, but it will be more difficult to keep warm in winter.
Unlike conservatories, sunrooms tend to have a conventional roof with brick, block or timber walls and light introduced through extensive use of windows, roof lights and glazed doors.
Most sunrooms are a structural addition to the home, so they are more likely to match and complement the existing structure.
Sunrooms are usually built in a combination of materials such as brick, blockwork, timber, PVCu, aluminium and timber.
Glazed doors can be sliding or bi-fold and normally lead out to the garden or patio. Floors are usually tile or stone, making them easy to clean and cooler in the summer months. Rugs and small carpets are often laid down in the winter to add more warmth.
One of the key considerations in designing a sunroom is the amount of natural sunlight to be introduced into the living space. As a sunroom is designed to use in all weathers, the use of glass is a major design factor.
Roof lights can be incorporated to add extra natural light from above, and there are many options on the market to meet your needs. With larger amounts of glass, it may be worth considering using specially coated glass to reduce solar gain in the summer months. Roman blinds can protect from strong sunlight without loss of aesthetic appeal.
And remember to include lighting options for those darker winter days. In winter, a sunroom will also need some form of heating if it is to remain comfortable. Design features should include high levels of insulation to make the space as thermally efficient as possible.
Background heat sources such as radiators, underfloor heating or even a wood-burning stove could figure in the design project.
Sunroom design, like that of conservatories', should consider the garden as much as possible, and the choice of doors and windows is hugely important.
Many opt for modern, fully glazed bi-fold or sliding doors that combine wide views with ease of use. Others prefer the traditional French doors for a more authentic feel, particular in sunrooms that use lots of timber.
The large window opening can provide instant ventilation in the summer but, for an all-year sunroom, you may wish to consider a ventilation system that keeps the air fresh in winter without pumping up those heating bills.
A sunroom extension may not need full planning permission. Much depends on its size and position. It may be classed as 'permitted development' if it extends fewer than 6 metres from a semi-detached house or 8 metres from a detached dwelling. It is fewer than 4 metres high and no higher than the existing roof below 30 square metres in floor space.
Other regulations apply if you plan to knock down a wall to add the sunroom extension and thermal efficiency rules will apply to any connecting door to the house. It is best to check the government's planning portal before starting any work but your installation contractor should know all details.