Keeping the heat in, & cold out
With the typical Edwardian conservatory having 14 glass roof panes & 14 side panes of glass (excluding the small opening lights), ie 28 windows that may need blinds, it is clear that a considerable amount of heat is lost through them, compared to a typical room which has 1 or 2 windows.
Numerous factors influence heat loss such as:
- quality of conservatory, with minimal draughts & energy efficient materials
- type of glass (modern day eg Pilkingtons xxx designed to efficiently retain heat; double or single glazed, the latter being the least energy efficient)
- polycarbonate (tinted on untinted, colour & depth of tint – bronze outside/ white inside thermally quite good, but the white (opal) inside does produce glare; 25mm or 35mm polycarbonate – the 35mm has lower U values at 1.4W sq.m., a good level of insulation).
- size & height of roof & sides
- Atmospheric conditions
Just as conservatories heat up very quickly in summer, they conversely lose heat very rapidly in winter as soon as the sun goes down. Warmth from the low sun enters the conservatory through the side windows, hits the floor & furnishings, & then rises vertically to be lost straight through the roof.
This means that roof blinds have far more benefit than side blinds during winter; indeed simply installing side (window) blinds in winter may have minimal effect on warming up your conservatory. Your (portable/ rad) heaters warm up the air which rises vertically & is also lost through the roof.
Glass such as Pilkington k or Pilkington Optitherm will help keep heat in during the winter & are a massive improvement on “normal” glass. But it is important to realise that such glass will only reduce the rate of heat loss, & often other measure are necessary in addition, such as good blinds & actual heating, to genuinely make the conservatory cosy all year round.
Pilkington glass will also be effective at keeping the heat in during summer, making the heat gain issue worse in summer! Another reason thermal reflective roof blinds are a good year round investment.
Multi Layer Insulation, or MLI, & aluminium backed fabrics, were developed as a result of the space program, & the need to keep the Apollo Space probe & astronauts in it, safe by reflecting solar heat whilst insulating the lunar module from the cold of space. This technology is today used in the production of roof roller blinds & some pleated fabrics.
MLI fabrics:
- Provide thermal insulation in combination with double glazing by the principle of multiple layers of polyester & aluminium stitched together.
- The exterior facing side of the roof roller fabrics are composed of real aluminium sheeting, 0.35mm ? thick, highly reflective to thermal radiation, which reduces both absorption by the fabric & emission. Heating from the conservatory is reflected back into the room below.
- Save up to an unparalled 50% of heat loss through a typical double glazed roof (source: the fabric manufacturer), resulting in a warmer conservatory on those dark winter nights. Other non metal foil solar coatings do reduce heat loss, but by a considerably lower percentage, typically 20%. Such coatings are widespread on the back of pleated fabrics, but because they let in much more light, they also let in much more heat in summer, & allow considerably more heat to escape in winter. See Fabric Performance Table.
For the choices available for reducing winter heat loss, click here.
For comparative analysis of Roof Pleated & Roof Roller, click here