Looking at the state of the UK energy situation, it’s no secret that homeowners are feeling the pinch. From October 2021 to October 2022, the average household energy bill in the UK skyrocketed by 54%, sending millions of people scrambling to find ways to heat their homes without completely bankrupting themselves, yet the government aid schemes don’t cut much of the mustard.
Well-known amongst the various methods is double glazing, an undeniably effective method that does away with energy-hungry single-glazed windows, providing homeowners with double-glazed windows. Unlike any half-baked measure that is just a temporary fix, double glazing offers long-term and lasting energy savings that year by year add up in a most remarkable way.
In this study, a Fleet homeowner takes centre stage in our journey that reveals.
On a human and tangible scale to show exactly what is possible.
The Fleet homeowner and her family had, like everyone else, witnessed an 54% spike in energy costs so she took the plunge and bought brand-new double-glazed windows. Her new found energy efficiency would give them financial respite and a brighter outlook on their economic horizon.
The Challenge – Rising Heating Bills in the UK
Looking at back on the past few years, the UK’s energy crisis has made the financial implications of heating her home a jarring reality for homeowners. According to Ofgem data, the average household now spends over £2,000 annually on energy bills, up from approximately £1,200 in 2020, forcing people to be ruthless with their finances, having to choose between heating their homes and other essentials.
Across the UK, homeowners are dealing with various window problems that contribute to these soaring energy costs. While some properties like The Fleet homeowner’s still have original single glazing, most windows in the UK have some form of very old double glazed sealed units that are now very inefficient and have exceeded their life span, breaking down with misting in-between the panes, seal failures etc. Whether single or old double glazing, the result is the same – homes are losing heat and money.
The Fleet homeowner’s situation epitomised this energy crisis. Living in a 1970s semi-detached home in Fleet, she witnessed a staggering escalation in her monthly heating bill, which jumped to a heart-stopping £320 by winter of 2022. It wasn’t hard to identify the problem and it’s not rocket science. Her home’s original single-glazed windows were letting go of all its heat. Making her boiler run overtime to pump up the temperature.
Coming from nowhere else, the property’s thermal efficiency had been severely compromised by its awful single-glazed windows. These windows have U-values of about 5.0 W/m²K whereas state-of-the-art double glazing has values of just 1.4-1.6 W/m²K, which is over three times more efficient. On top of that, The Fleet homeowner’s windows weren’t fitting well, allowing drafts to pour in, and the constant problem of condensation was turning into black mould in a lot of her rooms.
The Fleet homeowner’s Energy Performance Certificate rating reflected all of these issues, barely scraping a pathetic Grade E with a score of 42 points. Consuming nearly 15% of her household income, heating expenses have become too much for her, and she knew something had to be done.
Background Information
Looking at The Fleet homeowner’s property, the 1973 semi-detached house in the UK was a prime example of housing stock in need of thermal efficiency upgrades, and had the typical characteristics of the time.
Coming hotfooting back to the house’s construction, it had cavity walls, minimal insulation, a partially insulated loft space and the original, never replaced single-glazed windows. Well-known to be a recipe for disaster when it comes to heat loss, the state of the windows and doors before the replacement, made one thing very clear, the property was bleeding heat.
At 14 windows in total, plus the front door and French doors leading to the garden, The Fleet homeowner’s home had single-pane glazing which was perched in crumbling timber frames that had been battered by the changing Fleet weather. Loads of these windows don’t shut properly anymore, giving out chilly draughts and the silicone sealant around a few of the panes had cracked, sending cold air right into the house.
Old and new glazing systems couldn’t be more different in terms of heat retention. The single glazing in The Fleet homeowner’s house had a ghastly U-value of 5.0 to 5.8 W/m²K, depending on the condition of each window, whereas the double glazed windows she was considering would slash the heat loss to a U-value of just 1.4 W/m²K, effectively halving the amount of heat that escapes from the property.
The Fleet homeowner’s initial EPC showed her just how serious the problem was.
The property scored a paltry 42 points, and dropped into the Grade E bracket, and laid bare that windows and doors account for roughly 35% of the home’s total heat loss, making them the biggest contributor to the home’s energy consumption after the roof.
The Approach – Installing Double Glazing
And weighing the options between timber, aluminium and uPVC, when The Fleet homeowner finally decided to replace the windows in her property she chose A-rated uPVC double glazed windows after researching and getting quotes. Coming down to the pros and cons, the superior heat retention, very low maintenance requirements, a 20 year guarantee and being on a par with the other two alternatives won her over to uPVC.
The installation took five days back in September 2022 and was timed so that the project would be complete before the winter heating season began. Replacing all 14 windows, the front door and French doors, cost The Fleet homeowner £8,400, but because they did a complete job, she was able to get the biggest possible improvement in heat retention throughout her house.
Well-known principles of modern double glazing can help explain why the difference was so noticeable. The new windows featured modern sealed units that include a low energy coating that reflects heat back into the room and cuts off in extreme heat. They have an insulated cavity spacer bar stopping cold bridging and unsightly condensation line to the perimeter of the glass, and also have Argon gas fillings as extra insulation in the hermetically sealed unit cavity. The sealed unit sizes have been increased to 28mm as standard giving a very good insulation factor with an increased sound reduction. Triple glazing is also available giving a further increase both in insulation and sound reducing benefits.
The U-value of the whole window system, counting both the glass and the frame, came in at 1.4 W/m²K, a whopping 72% better than the original single-glazed windows. The uPVC frames also have built-in compartmentalised structures and thermal barriers that kill heat transfer around the edges.
In addition to the new windows, the installers sorted out the draughts around all the new frames so that there wouldn’t be any cold spots or air leaks, and fitted modern locking systems that lock down the windows tighter when they’re closed. The actual sealing of the new frames’ perimeters to the main fabric of the building was also addressed, stopping draughts around the actual frames – an area not normally considered by the customer.
Results – Energy Savings Achieved
Her house is now a lot more comfortable, and the data shows that her heating bills took a dramatic hit, when The Fleet homeowner had her double glazing installation she was blown away by the results, basically.
Well-known figures show that The Fleet homeowner’s average monthly heating bill plummeted to £198 in the 2022-23 winter, compared to the £320 she was shelling out the previous year, a cut of 38%, and over the full year, including the lighter heating needs in spring and autumn, she cut her annual energy costs by £1460, representing a 32% reduction in total energy spending.
From a technical standpoint, a follow-up EPC assessment in the spring of ‘23 revealed that The Fleet homeowner’s property’s rating had skyrocketed from a paltry Grade E (42 points) to Grade C (68 points), a 26 point improvement that was not just thanks to the new windows but also to the cumulative effect of plugging all the draughts and sorting out thermal bridging around the window openings.
Coming hotfooting home from a long day, The Fleet homeowner now doesn’t notice any cold spots near the windows anymore, and the temperature throughout the house is much more consistent, the damp issues that were causing mould growth in her bedrooms have vanished, because the new windows mean that the inside surfaces stay above the dew point even when it gets really chilly outside.
In terms of carbon emissions, The Fleet homeowner’s house now produces approximately 1.8 tonnes less CO2 every year.
That’s the same as taking a car off the road for about 4,500 miles. This reduction will be going to last for the entire life of the windows, which is roughly 20-25 years.
And the sound reduction was a lovely surprise, but it has completely transformed the way The Fleet homeowner uses her house.
The noise from the main road has been knocked down by around 30 decibels, and turns what were noisy rooms into peaceful spaces that are ideal for working from home, relaxing or sleeping.
Key Lessons Learned
When it comes to a double glazing upgrade in the UK, The Fleet homeowner’s experience and the subsequent analysis of her project can be of great value to fellow homeowners.
Coming from a property with single glazing, The Fleet homeowner’s energy bills were reduced by a remarkable 25 to 40%.
In the same range as to be expected by homes that are upgrading from older double glazing, which would yield more modest savings, about 10 to 15%. Well-known as the homes with single glazing are usually the ones that see the biggest returns on their investment.
The frame material also affects how much you’ll pay initially and how well the windows will last. The Fleet homeowner’s uPVC frames were the best compromise of heat insulation, sturdiness and affordability. Wood frames can get similar levels of heat insulation, but they need regular maintenance and are around 30-50% more expensive. Aluminium frames, being very low maintenance, unfortunately have lower heat insulation unless they’re fitted with thermal breaks, which sends the price soaring.
Combining double glazing with other ways to insulate the house will really maximise the savings. The Fleet homeowner is planning to add insulation to her loft and cavity walls, which should knock off another 15 to 20% from her energy bill, effectively sealing any leaks and making sure that no heat is wasted.
It’s also very important to have top-notch installation. The Fleet homeowner went with a FENSA-registered installer who provided guarantees and certification, and bad installation can knock out as much as a quarter of the expected efficiency. A couple of things that make or break the performance of the windows are accurate measurements, airtight seals, spot-on positioning of thermal breaks and no thermal bridging.
The upkeep for modern double glazing is a cinch, but needs to be done to keep the efficiency on track. Every year you should clean the drainage holes, lubricate the moving parts and swap out the weather seals every 15-20 years.
Conclusion
When it comes to reducing energy costs, The Fleet homeowner’s experience is a compelling example of the substantial and sustainable savings UK homeowners can achieve with double glazing, a 32% reduction in annual energy costs, or £1,460 per year. Will be coming hotfooting down the bank of household bills for decades to come.
This case study demonstrates that the Return on Investment of double glazing goes beyond just a reduction in energy bills, as the better EPC rating adds to the property value, the increased comfort levels send quality of life through the roof and the smaller carbon footprint is a contribution towards the environment. Putting it all together, double glazing is basically one of the best investments that any UK homeowner can make.
The massive leaps in thermal efficiency delivered by modern double glazing technology have taken U-values from as high as 5.0 W/m²K down to as low as 1.4 W/m²K, this kind of improvement is exactly what’s needed to knock down household energy bills.
If you’re currently freezing, particularly in a house with single glazing or faulty sealed units, The Fleet homeowner’s story should be both motivating and helpful. The instant warmth, years of financial savings, and a rise in property value make double glazing a very sensible investment that will keep on paying off year after year.
Don’t let another cold winter slip away with draughty, expensive windows. Contact Cristal Windows who is a local FENSA-registered installer to see how double glazing can sort out your energy problems and, like The Fleet homeowner, you’ll be feeling the benefits within a few weeks.
