Southern PVC Systems LogoWhite Window fitted to houseWoodgrain Window Kit

Southern PVC Systems Ltd.

Unit 1, The Carrick Business Centre,

Bonville Road, Brislington,

Bristol. BS4 5NZ


Tel:- 0117 9710359......Fax:- 0117 9720998


how to order
















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We manufacture high quality, energy efficient DIY PVC Windows and Doors. You can see our window prices online using our unique window and door price calculators. Our cost effective windows will enhance your home and help to minimise your energy costs. If you have any queries, please contact us for advice.


In this day and age, price and energy efficiency are two of the most crucial considerations for consumers who are shopping for DIY PVC windows. We strive to sell the most cost effective windows in our area. Our customers usually find that our rates cannot be beaten! Additionally, we make it easy for you towork out window prices online using our simple calculator tools. If you are interested in ordering DIY PVC windows from us, we will be quite willing to answer any questions you may have about energy efficiency first. The guide on this page should help you understand the basics.




window energy ratings



Window Energy ratings are A B C D E F Just like the labels on your new fridge/ washing machine.

A is the highest rating (most efficient), C is lower, and F is the lowest rating.
Building Regulations. From 1st October 2010,
The  building regulations require that a MINIMUM of C rating is used.
(or at least a U Value of 1.6 w/m2) 

Our Windows are made to A or B or C Rated

A rated is
Insulated frame, Mutichambered outerframe, Thermally reinforced Sashes & Mullions
with Glass unit. Low E Glass, Warm edge Spacer and Argon Filled.
B rated is
Insulated frame, Mutichambered outerframe, Thermally reinforced Sashes & Mullions
with glass unit, Low E Glass, Warm edge Spacer and Air Filled.
C rated is
Thermally reinforced or steel reinforced outerframe frame, thermally insulated sashes
With glass unit, Low E glass, aluminium spacer and air filled

A more detailed explanation......
The thermal efficiency of a window depends on the performance of both the Glass units and the frames.
The Specific calculations are quite complex, so to make it easier for the consumer to recognize the thermal quality of the windows, they have been banded into groups A, B, C etc.

Multi chambered frames are thermally more efficient than single chambered frames.
Most  frames are at least 3 chambered, the greater number of chambers increase the thermal efficiency,.

Latest Frame developments.....
We now have 5 chambers in the main outerframe profile  (See Photo above).
Thermal Inserts have also recently been introduced
These effectively increase the number of “Thermal chambers” in the sashes and Mullions.
At the same time, rigidity of the frame is enhanced, so that usually, no further reinforcement is required.
In some circumstances, such as woodgrain profiles, additional steel reinforcement is applied.
But as this is fitted within the Thermal inserts, then thermal losses due to conductivity of steel are minimised.
Tests have shown that Furniture screws, into the Thermal Inserts of the sashes give similar screw retention properties as steel. Another advantage is that screws will have less tendency to corrode when applied to thermal inserts, rather than steel (as the screws are fitted, they leave swarf which corrodes & breaks down the screw coating).

Double Glazed glass units......

28mm overall thickness (4-20-4)  (see diagram above).

Generally, the larger airspace the better the thermal efficiency (up to 20mm airspace)
The addition of Argon gas (90% by volume) also improves the thermal efficiency.
“K” glass (hard coat Low Emissivity glass) on the inner (room side) improves thermal efficiency by reflecting radiated (infra red) energy back into the room.
Soft Coat “Low E” glass does the same as “K”glass, but much more efficiently.
Aluminium spacer bar is less thermally efficient than the new “Insulating”  spacer Bar.


Triple Glazing    (U Value 0.8 w/m)   plus enhanced noise insulation

40mm overall thickness (4-14-4-14-4)   (see photo above).
2 inner panes, Soft Coat low E glass, Insulating Spacer Bar, Argon Filled
28mm overall thickness (4-8-4-8-4) where standard 28mm bead is required
Or can be used to upgrade existing frames, to enhance Noise and thermal insulation.
(note, 28mm triple glazed is slightly lower insulation value than 40mm triple glazed)

Our Frames

Synseal “Shield” 70mm system is internally beaded, chamfered bead.
We now use 5 chambered outerframe as standard (on White profiles).
We now use “Egress” (Fire Escape) hinges on all side hung windows

We have copies of Full simulation reports from Synseal Extrusions Ltd. for the A,B andC ratings.
Each report is 10 pages. And can be viewed at our showroom.
Copies are available by post on request.
The reports are prepared by an approved Simulator (080) by
British Fenestration Registration Council
BFRC reports noSYN-00124-3  SYN-001246

British Standards Compliance

Where applicable, our products comply with the following British Standards....

BS 7413

BS EN ISO10077-2

BS EN ISO 9002

Kitemark Licence no KM30983 (Frames)

Kitemark Licence no KM 27701 (Glass)



Southern PVC Systems Limited,

Unit 1,

The Carrick Business Centre,

Bonville Road,





Telephone:- 01179 710359

Fax:- 01179 720998




Monday to Thursday 8.30am to 4.30pm (up to 8.00pm by arrangement) Friday 8.30am to 4.00pm only. After hours and Saturdays main phoneline transferred to a mobile.