Double Glazing | Ultra Warm Glazing
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Double Glazing

Pilkington Optitherm S1 Glass, how does this glass keep in the heat?

We don’t want to bore you with science so here is the simple explanation for how our glass works, for a more detailed explanation and technical data, please see our technical brochure below.

The Pilkington Optitherm™ Range are high performance, coated low-e glass products specially developed for use in Insulating Glass Units (IGUs) to help with energy saving. Low-e glass has a microscopically thin, transparent coating – it is much thinner than a human hair – that reflects long-wave infrared energy (or heat) back into the room. The coating acts in much the same way as a flask or thermos, put something warm in there and it stays warm, put something cold in there and it stays cold. Put your heating on in your room and the room stays warm. That is the basic principle and it works extremely well.

Double Glazing - Graphic

If you would like a demonstration please call to our showroom where we can show you the insulating properties of the glass using an Infrared lamp. Our showroom at Johnstown Garden Centre is open 7 days a week.

For more technical details please refer to the Pilkington Optitherm S1 technical information here.

U Values, A Simple Explanation

Put Simply The U Value is like a speedometer, it is a measurement of the speed that heat moves through a material, the lower the U value, the slower the speed that the heat travels and therefore the better the insulation value. So put simply you should be looking for the lowest U value available, this will give you the highest insulation available.

To put some values on different types of glass, here are the U values for glass you will be familiar with:


Single Glazing


Older Double Glazing

no argon gas between the panes and no glass coatings



with argon gas between the panes and no coatings



Some Simple Maths

Here is a simple formula to use if you want to calculate how much heat loss can be prevented by changing your double glazing to Ultrawarm Pilkington Optitherm S1 glazing.

STEP 1 Calculate the area of the glass in your home, a typical home may have say 20 sqm
STEP 2 Guess from above what the U value of the existing glass is, a typical Dublin home built in the last 20 years will be 2.9
STEP 3 Use a relevant temperature difference between outside and inside, typically 10 degrees, 20 degrees inside and 10 degrees outside

Then multiply together 20 sqm by U value 2.9 by temperature difference 10 which will give you 580 watts.

Repeat the exercise using a U value of 1.0 and the result is 200, or a reduction of heat loss of 65%, just imagine how much energy is lost over the average 25 year lifespan of the double glazed units, and that’s before factoring in the comfort you will enjoy from your new cosy home.

If you would like to have this calculation carried out to see how much heat loss you can stop in your home by installing Ultrawarm Glazing then please contact us now for your free home consultation today on 045 844002.

When Not To Fit Ultrawarm Double Glazing

At Ultrawarm we only sell retrofit Pilkington double glazed units if they are going to benefit the homeowner. In some circumstances your windows may not benefit from new double glazing if

1.Your windows are very old, windows like all products have a limited lifespan, in our opinion if your windows are more than 25 years old then you should consider replacing the entire window. After 25 years your window may suffer from rubber gasket shrinkage, poor airtightness and old and worn hinges and handles. Replacing the glass in poor quality frames may not be a wise investment as you may have to consider replacing the entire window several years later, our expert team can inspect your frames and offer you free consultation and advice. If you windows will not benefit from new glazing then we promise we will not try to sell you replacement glazing, we can if required offer you a quote for new PVC windows and PVC and composite doors but only if invited by you the client.

2. If your windows frames are aluminium and suffer from condensation on the frames then replacement glazing will not solve this problem, condensation results from moisture in air in your home condensing on the cold surface of your window frames. While these frames may benefit from new glazing the condensation will persist.

Double Glazing - Fit

Our best results for homeowners have been from those having PVC window frames which are in relatively good condition, we can replace the glass and if necessary replace and upgrade locks and hinges, resulting in windows which perform like new at a fraction of the cost.

Home Renovation Incentive

Claim VAT Back on Your Ultrawarm Glazing

Save money during 2016 with The Home Renovation Incentive Scheme. By employing a qaulifying company such as Ultrawarm Glazing You can benefit from a tax rebate of the full V.A.T that you pay. Please see below for the detailed brochure on the scheme. This scheme is due to end on 31st December 2016 make sure you avail of this scheme before it finishes.

Home Renovation Incentive
Ultrawarm Glazing
Ultrawarm Skylights
Ultrawarm Windows and Door