A conservatory came with the house. It’s south facing.

In summer It’s lovely first thing in the morning and last thing at night. During the day it’s just too hot. It melts candles. Obviously in winter it’s too cold.

Any cheap solutions to make it useable?

Has anyone put up reflective silver on the ceiling etc?

It’s a plastic roof.

My long term plan is to replace it with an extension so I don’t want to spend too much in it.

We had a solid roof fitted to ours and have never looked back, it’s a perfect solution to the same problem we had. Makes a really light room. Ours cost about £10k and looks really nice inside and out. You get a vaulted ceiling inside and the metal tiles outside blend in fine with our house tiles.

This is the classic problem with conservatories!

As suggested above, anything you can do to turn it into a garden room is a winner.   A solid roof is best, but the most expensive, but good ceiling blinds or even blackout curtain lining between poles/fixings as a cheaper compromise.

Additionally the purchase of an oil filled radiator and portable AC unit whilst might sound extravagant, might be the difference between actually using the room on many days.  Stick ’em in the corner behind a chair.

Ours was a 5x3m sloping roof that was also unusable.  Fitted a plasterboard ceiling with super thick silvery insulation myself.  Next door neighbor plastered it for me.

Probably cost about £600. Oil filled heater for winter, no need for summer A/C in Scotland!

Room is used all the time now.  Wish we had done it years ago

Had ours built with a solid vaulted roof and would recommend that option. There is a system using Aluminium Struts custom cut to fit and highly insulated.

Our Garden Room sticks out into the garden and we adjust the windows for air flow in summer.

The one thing drives me mad are Hover Flies and Bees getting stuck inside and have to be rescued. We keep a butterfly net in there specially for reaching up into the ceiling.

Other than that top investment you will wonder why you didn’t do it sooner.