Many people complain of heat loss in a conservatory especially in the winter there are many causes for this and by taking these factors into consideration a conservatory can made a little warmer.
Changing the roof is not really an option without effecting planning regulations as well as extra strengthening of structure which is required when adding heavier structural support to the roof. One option however is to use solar control panels especially the upvc ones which in winter conserve more heat and in the summer allow heat to dissipate, these however will not make significant differences in the much larger conservatories.
Heaters are an option which are often used and a highly recommended option although expensive initially nut cheaper than using gas or electrical heat is air to air pumos which save you up to 3/4 on your electricity bill and can heat a conservatory really well but these have rules to their use which must be checked by the manufacturers to see if they are recommended for your conservatory.
An installer can be employed to check for leaks in the glass and improper fitting of roof panels and glass sheets in the windows and doors of the conservatory. Little problems even with gaps in the cills of a conservatory can have a profound amount of heat loss. so it is worth checking these.
Underfloor heating is a popular option in the UK and underfloor heating for tiles which are commonly used in conservatories are popular in the UK now.