How to Keep Your Loft at a Comfortable Temperature
If you want to avoid a loft room that’s too warm in summer and too cold in winter, take a look at this expert advice
If you’re planning a new loft conversion, it’s a good idea to think about these issues in advance. If your loft has already been converted but isn’t performing as it should, explore how you could upgrade it. From the right ventilation and insulation to the best window treatments, our experts explain how to keep your loft cool in summer and cosy in winter, so you stay comfortable all year round.
Professional advice from: Lydia Bradley of Visionary Lofts; Ana Mihaila of Atudori Construction; Jack Davey of LoftCraft London
“Hot air rises through a house, making the loft the hottest room in summer,” Ana Mihaila says.
Roof windows also have an effect. “Installation of larger glazed openings in loft conversions is becoming more common and this results in high solar gain,” Jack Davey adds.
At the other end of the spectrum, cold winters are still difficult to manage. “Many older homes lack proper insulation and are unable to handle temperature fluctuations,” Ana says.
Poorly insulated or under-heated lofts can quickly feel freezing, thanks to their proximity to the roof and multiple exterior walls; 25% of heat in an uninsulated home is lost via the roof, according to the Energy Saving Trust.
Despite all this, Lydia Bradley says, “Unfortunately, many homeowners don’t consider temperature control enough when converting a loft.”
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“It’s a requirement of Building Regulations that you have a proper means of heating a new loft conversion,” Jack says. “For example, a portable electric heater would not satisfy the requirements.”
“Depending on the loft size, one or two radiators may be sufficient to maintain a cosy temperature,” Ana says.
When it comes to loft radiator styles, Lydia says that large convector radiators are popular choices.
While most UK houses still have gas central heating, newer lofts might be heated by electric radiators connected to existing electrics, or radiators heated via a heat pump system or solar panels.
“Whatever heating system you have, extending that is always the most economical method,” Jack says. “Where clients have central heating, we normally find [a newly converted] loft is the first room to get up to temperature, and where a thermostatic valve is fitted, this will be the first radiator in the house to shut down once the room is up to temperature, as it’s typically the most well-insulated.”
A smart heating system will let you remotely control temperature through an app, and set individual room temperatures via smart valves.
Electric underfloor heating is another option. However, Jack cautions, “In our experience, this is best suited to tiled floors, so we recommend only installing it in the bathroom (if the loft will have one).”
“We’ve done wet underfloor heating for clients in their loft bedrooms, but this only really has the advantage of leaving more wall space and providing marginally higher efficiency,” he says.
“Good insulation is essential in both hot and cold seasons,” Ana says. “Not surprisingly, well-insulated lofts retain heat more effectively and reduce heating costs.”
But you might worry that insulating will cause your loft to overheat in summer. In fact, cavity wall or external wall insulation can help keep your loft cooler, because it can stop hot air getting in.
“It’s possible to retrofit insulation to current regulations, although you’ll be looking at a few thousand pounds,” Jack says. “It typically requires replastering of the loft, although some upgrades can be done in conjunction with re-roofing.”
“A 100mm-thick insulation material installed between the rafters and on the floor between joists, can significantly reduce heat transfer and maximise thermal efficiency,” Ana says. “It’s crucial to ensure insulation and plasterboard is fitted properly to avoid gaps.”
Don’t forget to insulate your eaves space as well, to prevent draughts.
More: Which Type of Loft Insulation Should I Choose?
The type of roof insulation you have can impact how warm your loft feels.
- A cold deck is when insulation is between the rafters and anything above it is cold; this is the traditional type of insulation, and requires ventilation between the insulation and roof deck.
- A warm deck is when insulation is fitted above the level of your rafters, as boards just under the roof deck; this option typically costs more.
“If a cold deck is your only option, avoid or minimise recessed downlights, as these compromise the insulation everywhere you install them,” he adds.
“Installing roof vents and well-insulated windows can enhance ventilation,” Lydia says. She also suggests fitting an openable skylight in the ceiling of your loft landing or stairwell to create airflow within your loft.
“One of the main things that homeowners can upgrade on is higher-spec windows,” Lydia continues.
Ana agrees. “Double-glazed windows with low-emissivity coatings can reduce heat transfer, keeping your loft cooler in summer,” she says.
Our experts also recommend installing blackout blinds or curtains to block out direct sunlight on hot days. “Awning blinds are available as a retrofit on most Velux windows manufactured in the last 10 to 15 years,” Jack says.
Portable fans can provide temporary relief, but if your room is likely to get very hot, you may wish to think about installing an air-conditioning unit during the construction phase, Ana suggests.
However, air-con is also notorious for guzzling electricity. In an existing room, a portable unit could be brought out when you need it on only the hottest days. Also look for units that run on ‘eco’ mode.
More: How Can an Eco Consultant Make My Home More Energy Efficient?
Other more energy-efficient ways to keep your loft cool include using reflective roof materials. “These can help deflect solar heat away from your home, reducing heat absorption and making your loft cooler,” Ana says.
“Flooring can also help to regulate temperature,” Lydia says. “Carpets can add warmth in winter, while hard flooring can be cooler in summer.” A thick rug that can be rolled up when not needed could be a good solution for lofts that experience both extremes.
Ultimately, Lydia says, “Proper insulation and ventilation are the keys to solving both temperature extremes. High-quality insulation keeps the loft warm in winter and cool in summer, while controllable ventilation allows you to manage heat and fresh air.
“When building a new loft, ensure your builders prioritise sufficient insulation, a well-ventilated roof space, and energy-efficient windows,” she says.
How have you kept your loft at a comfy temperature? Share your ideas in the Comments.