How Does Suspended Ceiling Insulation Work?
You probably keep hearing that insulation is the simplest way to cut energy bills and reduce energy waste. But why?
Hot air rises. You know this. It explains why hot air balloons float. It also explains why so often in a poorly insulated building your feet will feel like the coldest part of your body. Why does that happen? If you’ll permit us a brief wander into GCSE physics, we’ll explain.
Why does energy escape?
It happens because nature likes to even things out by redistributing the heat. In cold weather, the inside of a building will be much warmer than the outside, and nature will want to balance things out according to the second law of thermodynamics. That equalization can happen in a number of ways, one of which is convection.
In convection, hot air (eg from a radiator) rises. Unless something happens to stop it rising, it’ll keep going until it escapes the room and building entirely, where it can attempt to equalize the temperature outside with that inside. Of course, there’s usually at least once ceiling and a roof between it and the outside world and to pass through that the heat will switch convection for conduction. With conduction, matter absorbs and transfers heat (eg from one side of the ceiling to the other).
The easier it is for heat to escape, the more you’ll be left cranking up the temperature and wondering why your feet are still cold.
How does insulation work?
Insulation interrupts conduction by introducing a material which conducts heat poorly. If energy struggles to pass through it, more of the heat will remain in the room. And when more heat stays where you want it, you can afford to turn the heating down.
Do suspended ceilings insulate rooms?
Yes. The typical suspended ceiling tile will offer a good degree of insulation. But using additional insulation above your suspended ceiling can have a much greater impact for two reasons. First, because the ceiling is lower than the permanent ceiling above it, it doesn’t get as much space to rise before convection is impeded. Then, the ceiling with insulation above it inhibits thermal conductivity, and with less energy able to pass through, more warm air stays where you want it.
How much energy does suspended ceiling insulation save?
Pound note figures are difficult to establish because it depends on so many factors, from the efficiency of the boiler to the thickness of the insulation. It’s certainly the case, however, that suspended ceiling insulation pays for itself with a year or two in most applications.
For more certainty, let’s look at thermal conductivity – that’s the measure of how materials transmit temperature differences. The lower the rating the better the insulator a material is.
Glass, for example, will have a thermal conductivity rate of around 1W/mK (watts per metre kelvin). It’s not a good insulator (as you’ll know if you’ve ever pressed your nose to a single pane window on a cold day). Plaster is considerably better at around 0.5. A mineral ceiling tile may be as low as 0.06 W/mK. But ceiling insulation is lower still. This loft roll has a thermal conductivity of just 0.044 W/mK.
Alternatively, we can look at thermal resistance, which is a measure of how well a material resists heat. The better the insulator, the higher the R-value. A double glazed unit of glass might have an R value of around 1.7 m2k/w. Polyethylene foam or loose fill rockwool will provide an R value of around 3. But a 200mm suspended ceiling thermal insulation pad delivers 5.4m2k/w
On even a small scale – a single room or office, these insulating properties can prevent heat loss and lower energy bills. But on a grander scale, across the suspended ceilings of a school, hospital, hotel or office block, the difference can be significant.
Talk to us about cutting the cost of your energy bills, by paying attention to what’s above your head. Order suspended ceiling insulation now or call us on 01253 864902.