I've often mused that, because my window frames are grey, those strips of magnetic tape with a sticky back would go relatively unnoticed. As the recess between my frame and the glass is quite deep, 25 mm or so, I reckon I could quite effectively apply a tertiary glaze by having sheets of Perspex perimeter lined with the same self adhesive mag strip, and sticking them into place when I want them (winter) or removing them when I don't (summer, decondense!. Further, around half my glazing is actually sheltered (something like a conservatory) so I could tertiary glaze it externally or even quad glaze
By doing both sides

Perspex sheets look to be around 20£ per sqm, so I'd be looking at around 1000 quid to do the windows. The roof glazing might add another grand

In terms of house heating costs, I don't have a great idea of what my heating costs to run because we haven't been charting it long. Broadly speaking it looks like 30kWh/day in heating season and 20kwh/day out of it.

I've nearly 100sqm of glazing, not worried about the walls/roof as they're around 200/300mm of kingspan; it's the glazing that is the loss path I think

So, handwaving generalised values; is there any worth (money saving) in applying a system of tertiary glazing? I didn't buy triple at the time for several reasons including weight and price (quotes 50% more). As well as the money actor, there's a comfort factor too, as the bedrooms at 16 degrees cause a lot of complaints from the boss even though I like it: is adding another layer of immobilised air likely to appreciably improve the insulative value of the glazing (as compared to argon filled triple)?

I'd agree with djh - 30kWh per day in heating season is really quite low for a "normal" house. Just as a comparison, I have a 6 bed detached house, fairly well insulated and double glazed etc, in the London suburbs. Depths of Winter the heating is about 100kWh per day. In the Summer its zero - no heating May/June/July/Aug/Sept. Average gas use is 44kWh per day over the year, but that inludes HW and cooking.

Triple Glazing is often used in Scandinavia where they put in the 3rd layer of glazing for the winter. In the UK, if you've already got decent DG, I can't see it being worth the money or the faff.

Posted By: cjardBroadly speaking it looks like 30kWh/day in heating season and 20kwh/day out of it.

Hope I'm not hijacking the topic, but this is interesting: it corresponds pretty closely to *my* electricity usage: 28 kWh/day in heating period, and 18 kWh/day rest of year. (132 days x 28) + (233 days x 18) = 7890 kWh/year (for 190 m2).

However, we use wood heating on top, which comes out to 28 kWh/day also x 132 days = 3696 kWh / 2100 kWh/load = 1.76 loads x 100 Euros = 176 Euros for heating. Same electric would cost 630 Euros. Therefore I save 454 Euros a year by burning wood. This pays for one-half of our petrol bill.

Since we use very little electric heating (basically zero), I have often wondered why the electric bill evolves so: I suspect one part of it is the DHW tank, "warming the house"; and also more heated towel-rail usage. Nonetheless, I suspect that the major element is electric lighting: because "heating season" corresponds to "gloomy season", and we *do* tend to burn a lot of light, despite our best efforts...

Returning (finally...) to the subject of glazing, a ceiling fan might be a good way of dragging that high-up warm air off of the glass...

+1 for the curtains also...

gg

in that instance the bigger effect would have been the draughtproofing

Posted By: dimengineerI'd agree with djh - 30kWh per day in heating season is really quite low for a "normal" house. Just as a comparison, I have a 6 bed detached house, fairly well insulated and double glazed etc, in the London suburbs. Depths of Winter the heating is about 100kWh per day. In the Summer its zero - no heating May/June/July/Aug/Sept. Average gas use is 44kWh per day over the year, but that inludes HW and cooking..

I've no gas, so it's all electric here. The meter was reading about 2000kwh when we moved in, now on 10500. Some habits have changed - I didn't have a 1kw plasma TV during the summer, but having the comparison is interesting and helpful! How many people in your house? 2.4 in ours..

Interesting heat loss visualization conditions this evening, i note:

It's 0 degrees outside and little wind. A frost has settled on the roof windows and you can clearly see the heat loss path:

https://s13.postimg.org/8avl0hipz/IMG_1149.jpg

A side effect from summer is that part of the roof window set has a length of tyvek air guard- an aluminised roofing felt - sling from the underside. I did this to see if it would reduce insolation and room
Temps within the top floor.

https://s13.postimg.org/r37g4329j/IMG_1153.jpg

Not much, was the answer to the insolation theory, but I have been wondering whether this half millimetre thick membrane has trapped significant enough a layer of air to have had any difference on the heat loss in winter. It seems so, as this is a shot of sticking the camera through the open gap at the top and looking down along one of the roof bars where the membrane sags the most

https://s13.postimg.org/4ei94id5z/IMG_1151.jpg

It's so imprecisely slung I wasn't expecting much. But clearly just providing a bit of a barrier between the room air and a portion of air extending to approximately 8 inches beneath the glazing surface (roof bars are 4 inch deep) seems to have a dramatic reduction in the amount of heat lost via the rod bar

These bars are thermally broken, and the glass is warm edge spaced, but it does appear that a more dedicated thermal barrier would provide some advantage here; I just have to think of a suitable design. Perhaps some kind of sock for just the roof bar part that touches the room air would work, and not make things as dark as putting a barrier across the entire thing (like the air guard does, but a neater fit)

Any thoughts?