I know the benefits

of PVC-U windows.


Energy efficient


PVC-U windows and doors are energy efficient. PVC-U framed windows and doors reduce heat loss in winter by 28% compared with double glazed aluminum framed windows and doors.


Following table shows the R-Value of windows with different frame and glazing options. R-value is a measure of resistance to heat loss. The higher the R-value the better the insulation. (for more information refer www.design-navigator.co.nz )



Aluminum frame

Thermally broken aluminum frame

PVC frame

Single glazing clear

0.15 0.17 0.19

Double glazing clear

0.26 0.31 0.36

Double clear/low-e

0.31 0.40 0.48

Double clear/low-e+Argon

0.33 0.43 0.53


Above table is from BRANZ which is recognized by the building industry in New Zealand.


Multi-chamber profile design

In Europe there is window insulation testing standard. When calculate building insulation the testing result is used for windows and doors. But there is no such testing standard in New Zealand.


Different design can have different proportion of frame and glass which will result in different R value of the window. Some fabricators claim higher R value for their window systems. To claim higher R value based on one design is certainly not acceptable or misleading.  We hope that window insulation testing standard will be introduced in New Zealand so different window systems can be tested and rated.


Our premium series windows achieved 0.5 R value in insulation performance test. The tested window was double galzed with 5mm+12A+5mm glass and thermal spacer. PVC-U frames of the tested window accounts for 36% of the total window area.


Energy Efficiency is an important consideration when building your new home or redesigning an existing one. From the design phase you can incorporate features that will make your house energy-wise. When choosing products it’s possible to select items that deliver high performance without the power bill and high cost to match.


Window insulation minimum R value requirement for new building in New Zealand is 0.26 for most cases or 0.31 for some designs. Comparing with other countries our window insulation requirement is low. Minimum R value for windows is 0.5 in the UK and 0.58 in Germany.


With recurring energy shortages in New Zealand over the last few years, saving energy in the home has become a popular topic. While there is ongoing debate about how best to meet the country’s increasing demand for electricity, there are things you can do to reduce your electricity use, without compromising your lifestyle. You’ll also be mitigating the effects of climate change by reducing greenhouse gas emissions.


In each building, windows and doors play a decisive role for thermal insulation. With well-targeted measures you can exploit great energy saving potentials.  Owing to the characteristics of PVC-U, Homerit PVC-U windows & doors have excellent thermal insulation properties. The material itself has lower conductivity compared with metal frames. Plus the multi-chamber system gives Homerit PVC-U windows & doors further insulation ability.


WERS is the official Window Efficiency Rating System for comparing the performance of windows and doors installed in a typical New Zealand home. It uses a simple 5-star system to tell you how various window frame and glass options will perform. WERS shows that PVC/Timber frame is the best while aluminium frame is the worst. For more information about WERS, visit www.wanz.org.nz .