The Greening of Gavin

Cover Your Windows

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Did you know that glass can be the cause of around 10-20% heat loss in winter and around 25-35% heat gain in summer. 

Windows are not a very good insulator at all and are a bit of a mixed blessing. You can let a cool breeze flow through at the end of a hot day and it can let out VOC pollutants and cleanse the internal air. 

Double Glazing

So what can you do about this potentially unwanted heat loss and gain. Well, one solution can be double or triple glazing but it is an expensive fix to this problem.  Its benefits are that the pocket of air trapped between the two/three panes of glass prevent most of the heat loss/gain.  In colder climates it is well worth the capital expense over the longer term, and can save you a small fortune on your energy bills.. 

DIY Double Glazing

A much cheaper alternative is fixing a layer of bubble wrap, bubble side to the glass over the window frame.  It acts like a simple double glazing without the cost associated with it.  This works well, as my mate Mick demonstrated on his blog post titled “Cold Feet“.  He reports that it works very well.
As we have sliding windows in an aluminium frame (more heat loss through the frame) I could not place bubble wrap up against the windows as we still wanted to open them. 

Awnings

We did not choose to replace our windows with double glazing because there is a cheaper alternative which we already had installed, which is to cover the windows inside and out.
In summer we pull down heavy canvas awnings to the ground to prevent direct sunlight from entering the house from the north, and the east and westerly windows are underneath verandas. 
This stops most of the heat gain due to the pocket of air trapped on the outside of the windows between the glass and the awning.
In winter we roll the awnings all the way up to let in maximum light and heat causing a mini greenhouse effect in the living areas at the front of the house.

Natural Coverings

Since the photo of the awnings was taken, we now have two pear trees in pots that are growing well in front of the windows.  As these are deciduous  the leaves will block the heat in summer and let light through in winter.  A larger tree planted in the ground will have the same effect.  Do not plant an evergreen in front of you sun-ward facing windows.  This natural cooling/heating effect is lost.  

Curtains

Also with the aid of curtains, we also cover the insides of our windows on hot days and cold nights to stop heat transfer either way.  However, curtains must have a very important feature in which to work more effectively and that is to install a box pelmet.  

Closed Pelmets

Closed pelmets fitted to the top of blinds or curtains stop the air from flowing over the window pain and reduces heat loss in winter, and heat gain in summer.  Heavy curtains were the norm a while back, and are still a great option, but you can modernise with these options.

This example is a Holland blind with a closed pelmet in Kim’s office, which was installed during the last retrofit.  This room is on the south side of the house, but stays quite warm in winter.

The rest of the house has Vertical blinds, which are not as efficient as the Holland blind due to the many gaps.  All of these were installed before our greening, and had open pelmets.  We closed them off with some long pieces of cardboard and some duct tape.  This stopped the airflow behind the curtain and I am happy to say that it works well.

Shutters

Internal plantation shutters are another option which trap a pocket of air in the window frame acting like double glazing.  A little bit more expensive than fabric blinds, but work in the same manner.  

Summary

If you want to keep the heat in winter, and cool in summer, then you could do not better by covering your windows.  
Hopefully you now have some ideas to work on to save on those energy bills!  It certainly has helped us to reduce ours.

About Gavin Webber

Gavin Webber's daily goal is to live a more sustainable lifestyle, in an effort to reduce his family's environmental footprint so we can all make a difference for our children & future generations to come.

Learn more about him here and connect with him on Twitter, Facebook, and Google+.

Comments

  1. sailorssmallfarm says

    We were able to retrofit about 17 of our windows to thermal double glazed – the ones on the south side also have a coating which reduces UV coming in (south being our sunny side)- all entirely thanks to a “green” grant the federal government was offering, which was matched by the provinicial government – worked out to almost $100/window. WELL worth it. It was done last Feb (our winter), and we felt the difference immediately. For the remaining windows (all heritage age) which we could not replace without losing the architectural attractiveness, such as there is of it, we had storm window constructed – a cold climate answer to plantation shutters….they do the same thing, but we install them on the outside of the window through the cold season. I knew curtains were helpful, but never considered the need for a pelmet at the top – thanks for that tip!

    Reply

  3. suburbandigs says

    Thanks Gavin, I think I’ll need to look into getting an awning for our big North West facing lounge room window. It is on a gable wall and as such has no eaves. It’s wonderful in winter but is a massive pain during summer. I think this would do the trick. Cheers!

    Reply

  4. Pam says

    We are in the process of retrofitting our windows. We are sourcing the material from this company
    http://diydoubleglaze.com.au/
    Alan has been out to measure and the costs are very affordable.
    DH is doing the work one room at a time.
    You do need to be a handyman but it is very achievable.
    Cheers
    Pam

    Reply

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