Double Glazing

[mark99]

Is it worth bothering with the expense of double glazing (windows and portholes) on a new build?

 

I assume the advantage is less or no condensation but is this a reality?

 

TIA

 

 

Mark

[nb Innisfree]

I've fitted secondary double glazing to the inside of our ports and so far it is proving ok. Unlike sealed DG it allows us to close inner glass and leave outer open which keeps the space between ventilated and prevents/reduces condensation on glass and brass ports + there are no nasty draughts. Previous threads have suggested that sealed DG quickly loses its seal due to vibration. This breakdown of the seal is not uncommon in domestic buildings so I would think it's a bit of a non starter with boats (IMHO!)

 

Early domestic DG was the secondary kind and I think it was superior in many respects especially as it provides a bigger gap between glass, the only reason sealed was adopted was it's ability to use inert gas (nitrogen I think) as a means of reducing condensation

Edited October 4, 2009 by nb Innisfree

[Roger Gunkel]

The old condensation topic, must be the time of year.

 

The main advantage of double glazing on a boat, is the same as with a house, namely reducing heat loss. If your newbuild has quite a large window area, as opposed to small portholes, then the reduction in heat loss can be substantial. On my own wide beam, with 8x 1200x600mm windows, just using the cheap double glazing film, which cost less than £10 for the whole boat, made an incredible difference last winter. It cuts out the constant circulation of cold air dropping down from the cold glass and causing cold draughts through the lower part of the boat as the warm air goes up and through the windows. Double glaze the windows and you will even out the distribution of warmth throughout the boat.

 

A secondary effect of the double glazing, is that it removes the constant problem of condensation on the windows, as there are no cold glass surfaces for the moisture to collect on. Don't forget though that the moisture will still remain in the air to collect on other cold surfaces, usually enclosed hull side areas like under beds, backs of cupboard etc. It is important to keep moisture to a minimum and ventilate all enclosed areas well. Also while you are building, line all hidden surfaces that are likely to attract moisture condensation.

 

My own trials last year with the film were so successful, that I am awaiting delivery this coming week, of acrylic double glazing panels, which will be magnetically attached to my window frames for easy removal when required. The total cost for my boat is £230 which will be a tiny ammount for the saving in fuel and huge improvement in comfort.

 

Roger

[bridgit]

When chatting to a friend in the glazing business, he told me K glass in my port holes would be as affective as double glazing. Don,t know about windows but its a thought.

[Roger Gunkel]

When chatting to a friend in the glazing business, he told me K glass in my port holes would be as affective as double glazing. Don,t know about windows but its a thought.

 

I've no reason to believe that K glass doesn't improve the thermal qualities of glass, but if it was as good as double glazing, there would be no point in double glazing at all! It may reduce heat loss slightly, but the air gap of a double glazed unit gives a thermal break between the two layers, reducing heat loss drastically and removing the cold surface that condensation forms on.

 

Roger

[nb Innisfree]

When chatting to a friend in the glazing business, he told me K glass in my port holes would be as affective as double glazing. Don,t know about windows but its a thought.

 

Problem is it won't stop condensation on metal windows and portholes, and I have my doubts about a single pane being able to stop condensation.

[The Commodore]

I have PVC double glazing and i can confirm that condensation is no problem, the other main benefit we find is it is a great sound proofer against outside noise, ie, exhaust.

[bridgit]

I've no reason to believe that K glass doesn't improve the thermal qualities of glass, but if it was as good as double glazing, there would be no point in double glazing at all! It may reduce heat loss slightly, but the air gap of a double glazed unit gives a thermal break between the two layers, reducing heat loss drastically and removing the cold surface that condensation forms on.

 

Roger

 

 

No expert, but I believe k glass reflects heat back into room and deflects the cold air away. Maybe in time it will replace old double glazing. Who knows.

 

Bridgit

[frangar]

One of the troubles I think with boat double glazing is that there is no thermal break in the frame....unless someone can tell me otherwise....the other disadvantage is a broken window may be a lot harder to replace.

 

HTH

 

Gareth

[David Schweizer]

No expert, but I believe k glass reflects heat back into room and deflects the cold air away. Maybe in time it will replace old double glazing. Who knows.

 

Bridgit

Your understanding of the K glass qualities is correct, but it will never replace double glazing. It is now a requirement for the outside pane on all Conservatory double glazing units to use K Glass (or an equivalent)

[ITAfloat]

One of the troubles I think with boat double glazing is that there is no thermal break in the frame Correct, at least on my D/G chanelglaze windows. Then again nor do single glazed units ..the other disadvantage is a broken window may be a lot harder to replace. No harder, I would have thought, than a single glazed unit only more expensive. It is a complete sealed unit that sits in a frame.

HTH

 

Gareth

 

I have had two boats with single glazed units, and indeed used the plastic film on the bedroom windows to good effect. But it's a chore. Another benefit is the boat is much quieter with D/G, the glass does not drip condensate onto the bed or stick to the curtains, with that familiar black mould showing from the outside - yuk.

 

The only down sides for me was the initial cost and the frames are bigger - so the main doors are single glazed, to save it looking like a castle slit window and the sliders in the kitchen (no sliders in D/G )

Didn't have a problem with the frames being too wet last winter, so only time will tell.

Glad I've got them? Oh yes.

 

ITA

[Roger Gunkel]

Having used the double glazing film successfully last winter, I ordered some cut to size acrylic sheet last week. It arrived today, which was fortunate, as it was very cold here last night and the windows were covered with condensation this morning.

 

I had also ordered self adhesive magnetic seal, to attach the acrylic to the frames and started fitting at 5.30 this evening,. The windows are all aproximately 1200x600mm, with flat wooden surrounds, typical of most modern fitouts. I removed the hoppers, although the opening glasses would be self supporting on the frame if I needed to open any. My wife and I cleaned the windows thoroughly, and sealed the drainage holes with sealastic, then sprinkled some silica gel crystals from Wilkinsons into the channels, to absorb any moisture between the frames. We then stuck one half of the self adhesive magnetic seal tape to the outer edges of one of the sheets, making sure there were no gaps. The other half of the tape was then magnetically attached to the stuck tape, again allowing no gaps. We then peeled off the backing from the adhesive side and, after lining the sheet up carefully, pushed the sheet against the wooden frame, pressing it down hard all the way round. We had the whole job, seven windows, finished by 8.30.

 

Because the acrylic is glass clear and 3mm thick, it looks just like glass. We also used brown magnetic seal, which is far less obvious than white. The acrylic should also be a better thermal insulator than the film was, can be cleaned very easily and can be lifted off in seconds if required. Because it is attached to the wooden window surrounds, it also stops condensation on the aluminium window frames and the air gap is a good sound insulator. We may trim arround the edge with a wood strip, but it does look pretty neat already and is a vast improvement over the film. As all the sheets are the same size and only 4.5mm thick including the seal, they will all stack only 30mm deep behind the sofa for summer storage and of course are infinitely reuseable, taking only seconds to refit.

 

The whole lot was only £222.97 including delivery, which I think is peanuts for years of repeated use. If anyone wants a picture of a finished window or any info on an acrylic supplier, I'd be glad to post.

 

Roger

Edited October 8, 2009 by Roger Gunkel

[Mac Man]

Hi Roger, I would be interested to know where you got your materials from please?

 

Mac Man

[Gibbo]

Having used the double glazing film successfully last winter

 

As I've previously posted I did the same thing. It was an experiment and I didn't really hold out much hope for the idea. A cheapo film kit from Home Bargains. Cling film, double sided tape. Cost 15 quid to do the whole boat.

 

I can confirm that the difference it made was absolutely astounding.

[tomandsophie]

Roger, I would also be very interested to hear where you got your magnetic double glazing from. Can it be added to portholes too?

 

As I've previously posted I did the same thing. It was an experiment and I didn't really hold out much hope for the idea. A cheapo film kit from Home Bargains. Cling film, double sided tape. Cost 15 quid to do the whole boat.

 

I can confirm that the difference it made was absolutely astounding.

 

My only worry about using this system is that I don't want to damage our lovely oak window frames. Does the double-sided tape come off easily enough?

[Gibbo]

My only worry about using this system is that I don't want to damage our lovely oak window frames. Does the double-sided tape come off easily enough?

 

It doesn't come off particularly easily. But it didn't do anything to the varnish. I suppose it could do if the varnish was badly applied.

[Roger Gunkel]

Sorry I didn't get back to answer the questions yesterday, but didn't get back to the boat until 2.30 this morning after blowing a head gasket

 

The company that I used is 365plastics.com LINK They were extremely helpful even though I twice rang them with stupid questions after ordering online. They were also brilliant at chasing up when the courier failed to deliver next day.

 

To order, go to the link, click on the Ecoglaze double glazing panel near the top and it takes you to the right bit. You order a panel from which they cut the size that you want. You pay for the full panel, but they don't charge for cutting it. I used the 3mm acrylic which is plenty thick enough for boat windows. They also supply the magnetic self adhesive seal in 15metre rolls.

 

As Gibbo says, the adhesive tape doesn't come off easily, although meths dissolves the adhesive pretty well and a good deal of rubbing will remove it. I had to do that after removing the film this Spring, otherwise you have a sticky mess round your frames. I have used brown magnetic seal for the acrylic double glazing this year, and will leave it on next spring ready for next year as it doesn't look too bad and there will be nothing at all to do next time.

 

Edited to answer Tom, technically it would work on portholes, but practically you might have difficulty curving the magnetic strip around the frame, particularly as the strip on the window has to fit exactly on top of the strip on the frame, for the magnet to work properly.

 

Here's a pic of one of the finished windows

 

Roger

Edited October 10, 2009 by Roger Gunkel

[O'Mali]

the only reason sealed was adopted was it's ability to use inert gas (nitrogen I think) as a means of reducing condensation

I think you will find it is Argon and some bright spark has developed a window that can be clear and turned "frosted" at the flick of a switch by passing HT voltage through the gas much like a coloured cold cathode tube that some people call neon lights (Neon glows red when HT voltage is passed over the electrodes, Argon is blue but creates white, green, blue and yellow "Neon" tube colours when the tube is lined with powders)

[Gibbo]

I think you will find it is Argon and some bright spark has developed a window that can be clear and turned "frosted" at the flick of a switch by passing HT voltage through the gas much like a coloured cold cathode tube that some people call neon lights (Neon glows red when HT voltage is passed over the electrodes, Argon is blue but creates white, green, blue and yellow "Neon" tube colours when the tube is lined with powders)

 

It is indeed usually argon. The heavier the gas, on the whole, the better the insulation. Argon is a compromise between heat insulation and the cost of the gas.

[nb Innisfree]

It is indeed usually argon. The heavier the gas, on the whole, the better the insulation. Argon is a compromise between heat insulation and the cost of the gas.

 

Years ago I tried CO2, big mistake! continually absorbed moisture and made the situation worse.

[Doorman]

The old condensation topic, must be the time of year.

 

The main advantage of double glazing on a boat, is the same as with a house, namely reducing heat loss. If your newbuild has quite a large window area, as opposed to small portholes, then the reduction in heat loss can be substantial. On my own wide beam, with 8x 1200x600mm windows, just using the cheap double glazing film, which cost less than £10 for the whole boat, made an incredible difference last winter. It cuts out the constant circulation of cold air dropping down from the cold glass and causing cold draughts through the lower part of the boat as the warm air goes up and through the windows. Double glaze the windows and you will even out the distribution of warmth throughout the boat.

 

A secondary effect of the double glazing, is that it removes the constant problem of condensation on the windows, as there are no cold glass surfaces for the moisture to collect on. Don't forget though that the moisture will still remain in the air to collect on other cold surfaces, usually enclosed hull side areas like under beds, backs of cupboard etc. It is important to keep moisture to a minimum and ventilate all enclosed areas well. Also while you are building, line all hidden surfaces that are likely to attract moisture condensation.

 

My own trials last year with the film were so successful, that I am awaiting delivery this coming week, of acrylic double glazing panels, which will be magnetically attached to my window frames for easy removal when required. The total cost for my boat is £230 which will be a tiny ammount for the saving in fuel and huge improvement in comfort.

 

Roger

 

A touch puzzled by this comment, as our window frames are aluminium (non-ferrous) and cannot be magnetised!

[wrigglefingers]

A touch puzzled by this comment, as our window frames are aluminium (non-ferrous) and cannot be magnetised!

Good point but mine were steel on my old boat.

[Lesd]

Sorry I didn't get back to answer the questions yesterday, but didn't get back to the boat until 2.30 this morning after blowing a head gasket

 

The company that I used is 365plastics.com LINK They were extremely helpful even though I twice rang them with stupid questions after ordering online. They were also brilliant at chasing up when the courier failed to deliver next day.

 

To order, go to the link, click on the Ecoglaze double glazing panel near the top and it takes you to the right bit. You order a panel from which they cut the size that you want. You pay for the full panel, but they don't charge for cutting it. I used the 3mm acrylic which is plenty thick enough for boat windows. They also supply the magnetic self adhesive seal in 15metre rolls.

 

As Gibbo says, the adhesive tape doesn't come off easily, although meths dissolves the adhesive pretty well and a good deal of rubbing will remove it. I had to do that after removing the film this Spring, otherwise you have a sticky mess round your frames. I have used brown magnetic seal for the acrylic double glazing this year, and will leave it on next spring ready for next year as it doesn't look too bad and there will be nothing at all to do next time.

 

Edited to answer Tom, technically it would work on portholes, but practically you might have difficulty curving the magnetic strip around the frame, particularly as the strip on the window has to fit exactly on top of the strip on the frame, for the magnet to work properly.

 

Here's a pic of one of the finished windows

Roger

 

Hi Roger,

This sounds like a great idea, the finish in the picture is very tidy. One question; you mention on your earlier post that you need to keep good ventilation or you may have problems with condensation on other surfaces. We get lots of condensation of our windows currently and if I fitted this secondary glazing then apart from mushroom vents and swan hatches I dont have any other means of ventilation (I normally leave a few windows cracked open slightly around the boat). I'm concerned that everything that used to form on the windows could appear elsewhere in affect I'd just move the 'problem' from the windows to elsewhere. What was you experience when you first stated with the seconday glazing idea, how did you combat the above issue ?

Rgds

Les

[nb Innisfree]

Hi Roger,

This sounds like a great idea, the finish in the picture is very tidy. One question; you mention on your earlier post that you need to keep good ventilation or you may have problems with condensation on other surfaces. We get lots of condensation of our windows currently and if I fitted this secondary glazing then apart from mushroom vents and swan hatches I dont have any other means of ventilation (I normally leave a few windows cracked open slightly around the boat). I'm concerned that everything that used to form on the windows could appear elsewhere in affect I'd just move the 'problem' from the windows to elsewhere. What was you experience when you first stated with the seconday glazing idea, how did you combat the above issue ?

Rgds

Les

 

We have done the same thing but with sliding glass, fitted some of it in the winter and didn't notice any more condensation elsewhere. Important that outer window is kept open or slightly open.

 

Finally fixed the remainder this summer so will be able to test it this winter but so far we have had a vast improvement.

[Roger Gunkel]

Hi Doorman,

 

You probably missed my post after the one you quoted, as I explained that the magnetic tape is attached to the window frame and the acrylic, with self adhesive backing. It doesn't matter what the frames are made out of. As you can see in my picture, the strip is attached to my wooden frames.

 

Les,

 

As Nb Innisfree said, the moisture doesn't neccessarily settle elsewhere, only on existing cold surfaces. It will still be in the air, but as there will be less cold spots, there will be fewer surfaces for condensation to form. This is the same with a house, where the moisture stays in the air in a well insulated house, whereas in old single glazed and single walled houses, there always used to be condensation on widows in the mornings and mould build up on cold hidden wall surfaces.

 

You still need a circulation of air, but in our boat, that is easily accounted for by mushrooms, side hatch, door vents, doors and rear hatch. With our magnetic DG, we can also instantly lift off any DG unit if we should want to open a window. If you think about it, there is probably a lot more ventilation in a boat with the windows and doors shut, than there is in a house with rubber seals on all modern DG windows and doors.

 

Nb Innisfree,

 

Surely if you keep your outer window open all the time behind your double glazed unit, you will loose the whole point of inner glass, as the air in between the two will just drop to the outside temperature, making the inner one cold aswell, and transferring the heat from the boat!

 

Roger

Edited October 15, 2009 by Roger Gunkel