With ever increasing heating costs, the insulation value or the ability of your new uPVC conservatory to retain heat during the colder months of the year is becoming an even more important factor to consider.

If you are considering adding a conservatory to your home during the warmer months of the year, it is possible that you may overlook the fact that you will have to heat it efficiently during the winter months in order that you can utilise it as a year round extension to your home.

Considering how you will heat the conservatory is one issue but the most important factor will be how efficient the conservatory will be in retaining this heat. There is little point in adding an expensive heating solution such as underfloor heating if your valuable heat is going to disappear through the glass, roof or frames of the conservatory.

This is particularly important at the lower end of the market where you can still buy a basic specification conservatory that does not include any type of heat retaining glass and the roof is glazed using 16mm or 25mm polycarbonate. These products may appear to be bargain price conservatories but the lack of good insulation properties could mean that they could be very expensive to heat during the colder months of the year or possibly 'off-limits' for this period.

In the UK insulation values or 'U' values are currently used to measure a product's heat transfer and the lower the 'U' value the better the insulation value, which means less of your valuable heating will be lost 'through' the product.

Target 'U' values for the three main elements of an energy efficient PVCU conservatory are likely to be:

• Glass Conservatory Roof = 1.1w m/2k
• Polycarbonate Conservatory Roof = 1.5w m/2k
• PVCU Frames = 1.8w m/2k
• Sealed Units = 1.1w m/2k

• Glass Conservatory Roof - should include a low E internal glass surface, even if you are selecting solar control glass for the exterior surface. Sealed units should preferably be argon gas filled for optimum insulation.

• Polycarbonate Conservatory Roof - 35mm thickness is more efficient than 16mm or 25mm thick.

• Sealed Units - should include heat retaining glass such as K glass as a minimum or even better, a soft-coat Low E glass. Units should preferably be Argon Gas filled for optimum performance.

The performance ratings of PVCU windows and doors are currently undergoing a change with an easier to understand rating system being introduced. The new window energy ratings are similar to those already found on many electrical items with a seven band A - G rating system, with A being the most energy efficient. This system is not a statutory requirement but is being voluntarily introduced to allow consumers to make informed decisions on the energy performance of competing products.

At the present time, Conservatories are not subject to building regulations in England and Wales, which means that unlike replacement windows and doors for your home, there are no enforced standards of insulation applicable.

However, since the purpose of adding a new conservatory to your property will doubtless be to increase your living space all year round it is ultimately very much in your interests to check the insulation value or energy performance rating of the components used in the manufacture of your new conservatory to ensure that it does not become a 'white elephant' during the colder months of the year.

There are bargain price PVCu conservatories in the market place, particularly in the DIY or self build conservatory field where prices are very competitive. The choice and difference in specification can prove daunting to the uninitiated and you will need to consider the performance of each product carefully, not just the cost.

The insulation value of your new conservatory is a very important point to consider at the planning stage, since there will be little you can do to make this permanent extension to your home more energy efficient once it has been installed.