Energy efficient
Windows and doors play an important role for thermal insulation of a building. With well-targeted measures you can exploit great energy saving potential. Due to the characteristics of PVC-U, Homerit PVC-U windows & doors have excellent thermal insulation properties. The material itself has lower conductivity than metal frames and the multi-chamber system gives Homerit PVC-U windows & doors further insulation ability.
PVC-U windows are used in 80% of the world, and have been used for more than 50 years. PVC-U is much more energy efficient than aluminium. At 25°C aluminum thermal conductivity is 205 w/mk while PVC thermal conductivity is only 0.19 w/mk.
In a letter to BUILD magazine published in 2006, Ken Miller – former President of the UK Federation of Master Builders wrote: “After all, the Europeans have been building far longer than us and it’s about time we took a leaf out of their book. … Otherwise New Zealand will continue to build shoddy, leaking, damp and inefficient homes for years to come.” To download a full copy of his letter, click here < Look to other countries to build wisely>.
In addition to standard double glazing we can provide five types of Low E double glazing and one Low E triple glazing options. Low E coating can further improve thermal insulation.
On 29 November 2021 MBIE published new Building Code – H1 Energy Efficiency Acceptable Solution H1/AS1. To download a full copy, click here < Building Code H1/AS1 Fifth Edition >.
Minimum construction R-values for windows and doors will be R0.46 for most of the country, R0.50 for lower South Island for building consent applications submitted after 2 November 2023.
R-values of Standard Size Homerit PVC-U Windows
| Glazing Ug (W/M²K) | R-value (M²K/W) |
| 2.63 | 0.41 |
| 2.27 | 0.46 |
| 2.02 | 0.50 |
| 1.60 | 0.58 |
| 1.30 | 0.67 |
| 1.10 | 0.74 |
| 1.00 | 0.78 |
| 0.90 | 0.82 |
| 0.60 | 1.00 |
- R-values are from BRANZ Appraisal No. 543[2022] for a standard window
- Ug of classic double glazing is 2.63W/M²K
- Ug of double glazing with high performance Low E and Krypton gas can reach 0.9W/M²K
- Ug of triple glazing with high performance Low E and argon gas can reach 0.6W/M²K
- R-value of aluminium windows with classic double glazing is 0.26W/M²K
- R-value of thermally broken aluminium windows with classic double glazing is 0.32W/M²K
For Homerit BRANZ appraisal certificate and technical literature, visit < BRANZ appraisal No. 543 >.
