Energy Saving Measures - very basic

Telegraph_Sam

It has always surprised me when in discussions over energy saving there is hardly ever any mention of what must rate as the lowest cost but arguably most cost effective measure one can implement: Investing in heavy lined curtains and keeping them drawn whenever possible.  Effective from both a physical and a psychological point of view - I feel "cold" when I go into a heated room with "bare" windows, and would have to up the heating thermostat by more than a degree to compensate.
The explanation must be that there is not enough money in it, compared with double glazing and such like, to justify promoting such unromantic technology. Or am I being too cynical?

quartzz

Something I heard from someone, somewhere. you don't keep heat in, you keep the cold out. well, there you go. could save you £50 a year

I can tell you that my kitchen has always been cold (first winter in this house) despite having a decent radiator. culprit? patio doors in the kitchen. literally - the kitchen walls are wall-temperature. but the glass on the patio doors is....."cold" (under 10 C). I basically have a fridge cooling element, taking up a 2 by 2 metre space on the wall

I could agree though....and can give a couple of examples. but hard surfaces (glass, lino) seem to give a colder environment than fabric surfaces

Telegraph_Sam

So does your kitchen boast a window with lined curtains??

QrizB

Interesting idea.

Telegraph_Sam said:

Investing in heavy lined curtains and keeping them drawn whenever possible.

Today, outdoor temperatures around my home peaked at 1.3 degrees C. Not exactly warm!

Nevertheless, I was sure to open the curtains wide.

Why? Well, it was a bright sunny day. Sunshine entering my home through the windows warmed my house significantly. My bedroom, for example, warmed from 18.0C at 1000 to 19.6C at 1400. My CH thermostat and TRVs normally keep my bedroom around 17C during the day.

Telegraph_Sam said:

The explanation must be that there is not enough money in it, compared with double glazing and such like, to justify promoting such unromantic technology. Or am I being too cynical?

Double glazing is likely to be much more effective at keeping heat in than a single glazed window with heavy curtains.

Per Wikipedia:

Typical thermal transmittance values (U-values) for common building structures are as follows:

• Single glazing: 5.7 W/(m2⋅K)
• Single glazed windows, allowing for frames: 4.5 W/(m2⋅K)
• Double glazed windows, allowing for frames: 3.3 W/(m2⋅K)
• Double glazed windows with advanced coatings: 2.2 W/(m2⋅K)
• Double glazed windows with advanced coatings and frames: 1.2 W/(m2⋅K)

Per this window company, current standards for windows require a U-value of 1.2 for new windows and 1.4 for replacement windows.

Now, I don't know exactly how insulating your curtains will be. However I can get an value for sheeps-wool insulation; a 10mm thick layer would have a U-value of 4.2. Now, you might have super-duper curtains that insulate better than a 10mm thick later of sheeps wool, but I suspect you don't.

For another comparison, a 4.5 TOG summer-weight duvet has a U-value of 2.2. A 10.5 TOG duvet has a U-value of 0.95. So if you replace your curtains with duvets and fit them closely enough to avoid draughts, you might get similar performance to modern DG windows.

(A TOG is a thermal resistance of 0.1 m²K/W. So dividing the TOG value by ten, then taking the reciprocal, gives the equivalent U-value.)

pseudodox

My sitting room has full height full width (14ft) patio doors at one end.  Curtains are lined but not particularly thick fabric but by keeping them closed when it's really cold (being plain cream fabric they let a lot of light through) they make a huge difference to room temperature.  Currently the room is 19C & very cosy.  A thermometer hanging between the curtains & the glass currently reads 15C.  Quite a difference.

teaselMay

The main heating in my living room most days is the low winter sun

Telegraph_Sam

@QrizB Several points:

My comparison was between a given window with and without thick lined curtains

I used the term "cost effective" intentionally. Obviously you are going to get improved results as you progress through triple glazing with fancy insulating enclosed gas (argon??) and onwards - at a price

I have a full width southern facing living room window with heavy lined curtains. This accentuates what you refer to. I get a large benefit when there is strong sunlight when of course the curtains are drawn open. BUT the reverse is true if (in winter) I omit to re-close the curtains as the sun sinks. I can see the kW's escaping back out (almost). What I meant with "whenever possible".

The psychological comfort aspect: I can go into a room with double glazing. I can "feel" several degrees warmer depending on whether the curtains are drawn or not, with the same thermostat setting.

In summary. Thick lined curtains is a much under-rated technology given short thrift by advisers and the industry alike for what I suspect are not the most noble of motives.

quartzz

Telegraph_Sam said:

So does your kitchen boast a window with lined curtains??

the kitchen has a smaller window which has a net curtain over it, and the patio windows have some larger draped curtains in front of them. I moved in 2 months ago so haven't really had a chance to fine tune the curtain situation, and this is the first winter I've been here so this is the first time I've actually known what the temperature in there is like

the most effective draught exclusion I've done so far is make sure the tumble drier door is closed - the elephant duct to the hole in the outside wall literally acts like an outside draught "injector"

the point of my message was---I guess, that (as agreeing with your comment) any panes of glass turn into large cold surfaces, which basically act like a refrigerator surface which "emanate" cold

pseudodox

Two hours later my room is still at 19C, whilst the thermometer between curtains & window has dropped to 13C.  Pretty effective for lightweight fabric.

Telegraph_Sam

If I'd read that in a double glazing glossy brochure I would have had them up under Trading Standards.

Green_hopeful

Secondary magnetic glazing is relatively cheap to install and reportedly makes a big difference to condensation, temperature and noise. You can do it yourself. I keep looking at our windows but I will need to remove some of the window frame to fit them. Our windows are already double glazed but with narrow air spaces and wooden frames so we have interlined curtains for heat.