Many of you will know from my rants on Twitter that I am not a huge fan of UPVC double glazing replacement windows fitted to older style property. Too often, we are in the habit of ripping out lovely old windows which could easily be repaired and even made just as good thermally as double glazing. To some degree I think we have been brainwashed by double glazing companies into thinking it’s the only answer.
Will Replacement Double Glazing Save You Money?
There have been claims that double glazing can cut heat loss by half, and that it’s a big money saver on fuel bills, but is this strictly true or have the figures been hyped? At best if we were to assume that you only did your windows and no other insulation, then you should reduce your overall energy bill by between 5% and 10% in the average house. However, in order for that fuel saving to be worth the initial expense, then you could be looking at anything from 18 to 65 years to get the cost of a standard £5000 installation back on an average 3 bed house, with gas fuel taking the longest to pay you back.
UPVC Double Glazing Is Not The Only Answer
On older style property badly fitted or the wrong style of double glazing chosen can detract from the value. Additionally, UPVC in particular are very bad for the environment. Waste disposal is a difficult problem because they do not break down very easily, if at all. Also, the manufacture of UPVC uses large amounts of energy which is not great for the environment.
So is it really worth it, and what can we do instead?
- Replace the glass with a double glazed unit if the window style permits. A good carpenter can widen the slot the glass was in which can then be changed for the thinner double glazing options.
- Get the window draft proofed when its renovated by using a system like Ventrolla. Most of the heat savings are about better draft proofing.
- For winter, hang thermal backed curtains, this has the added benefit of being able to change them for lighter summer ones.
- Don’t rip out full window, just replace the existing glass with Pilkington thin glass. It has the similar thermal properties standard double-glazing.
- Seal up around windows with caulk to stop heat escaping.
- Hang secondary double glazing instead and take it down in summer.
Save Yourself Money
Finally, if you are considering replacement windows in UPVC at least make an effort to have ones which fit the style of the building ( like the picture at the top of this post.) You can save yourself substantial amounts per window if you fit them to the existing wooden sub frame ( if it’s not rotten), and, you’ll find there will be less mess and ‘making good’ to do afterward. Unless your frames are completely rotten its not necessary to replace them, they can easily be repaired. Don’t let the window company talk you into ripping out the whole lot.
Remember, old houses need to breathe to a certain degree, and were not made to be airtight, which can contribute towards damp in older housing if air flow is restricted.
NB: (Remember, current building regs state they must be fitted with low emissivity glass (sometimes called ‘low-E’ or ‘K-glass’). Look for FENSA registered installers.)