What windows to get?

[Graeme Roche]

Good afternoon All

 

We are the (long) process of doing up our 2001 50ft John White boat and have decided that we would like to replace the windows.

 

My questions to you are?

 

1) Single or double glazing? We understand the benefits of double glazing but is the extra cost worth it?

2) What manufacturers have people used and had both good and bad experiences with?

 

Any advice/feedback greatly appreciated.

 

Graeme

[Naughty Cal]

If you are going to the trouble of replacing the windows then surely double glazed is the way to go?

[Guest]

XP?

 

Hang on wrong thread.

 

(I too would go double glazed if you can afford it.)

[Ray T]

Windows 10 - Whoops sorry wrong thread.

[Guest]

Great minds??

[bag 'o' bones]

I can see the benefits of double glazing in terms of reducing condensation although I don't think it will prevent it on the frame itself.

 

There was a thread on here a while back in which some reported a high failure rate of the sealed units - presumably due to the constant expansion and contraction.

 

Perhaps a non sealed secondary glazing system would be more suitable on a boat? Might solve the frame condense problem at the same time.

[Cheshire cat]

What do you expect the double glazing to achieve?

My experience is that 10mm gap doesn't really hack it. We have 10mm. where I am currently working and there is still a significant cold downdraught from the panes.

 

Increasing the gap would improve things but on the boat probably wouldn't look aesthetically pleasing.

[Chewbacka]

I have 15" portholes which are single glazed which are fine. But the benefits of double glazing will increase as the surface area goes up. Lots of 'normal' size or a few very large windows would benefit from more insulation. Do you have a lot of window area to justify double glazing?

[Machpoint005]

Since you need a fair amount of ventilation, I would not think it was worth going for double glazing. The surface area of walls, roof and floor will be an order of magnitude greater than the total window area (even with bus windows) so the additional expense isn't worth it, bearing in mind you WILL have to open the windows.

[ditchcrawler]

Are you going to use it in the winter?

[Neil Smith]

I have used Caldwell windows and very pleased with cost, quality and service.

 

Neil

[blackrose]

Since you need a fair amount of ventilation, I would not think it was worth going for double glazing. The surface area of walls, roof and floor will be an order of magnitude greater than the total window area (even with bus windows) so the additional expense isn't worth it, bearing in mind you WILL have to open the windows.

Why WILL be have to open the windows? The only reason I open my windows in winter is to vent steam from cooking and from the bathroom when I'm taking a shower. Otherwise they all stay firmly shut in winter. I've never understood the "ventilation mantra" on this forum. In general, boats should have plenty of non-closeable fixed ventilation without needing to open windows.

 

I disagree that it isn't worth having double glazing if you can afford it. So what if the surface area of the rest of the boat is larger by orders of magnitude? The rest of the boat is insulated and single glazed windows aren't! That's like saying it's ok to scrape off a 4ft2 area of your sprayfoam because the majority of the boat it's still insulated?

 

Have a look at an occupied boat with a thermal imaging camera in winter and see where all that heat is coming out (apart from the chimney)，then you might change your mind.

 

But if you're going to install double glazed units then they should be good ones because cheap ones aren't built to flex and will allow moisture between the glazing leading to mildew.

Edited December 2, 2015 by blackrose

[Graeme Roche]

Thank you all for your feedback and advice.

 

The aim would be to reduce condensation, ultimately, as the boat, although not a live a board, will be used all year round.

 

We're fitting solar vents as well which, according to calculations, should give us plenty of ventilation.

 

It's all about weighing up the cost/benefit add the double glazed will come in at nearly 2.5k, and about half that for single.

[ditchcrawler]

 

 

We're fitting solar vents as well which, according to calculations, should give us plenty of ventilation.

 

 

Calculations: I think you have to calculate for sufficient ventilation without being solar powered

[DHutch]

I think it depends on budget and the boats intended use.

 

For predominately summer/seasonal use, perhaps with occasional winter use, we have no issues at all with single glazed windows and single piece aluminium frames and I would not see any real reason to pay more on alternatives.

 

However if I was planning to live on the boat throughout the year, I would seriously be considering alternatives, double glazing, split/insulated frames if the budget allowed and I could find units I was happy with.

 

 

Daniel

[Mitchellmoxo]

I have a mould for 12" portholes if your looking for a budget option ? cost me about £150 including glass for 9 portholes

[Jayseaess]

_{We plan to use the Thermal Break double glazed units from Wesley Windows in our new build, this then helps with the condensation on the frames}

Edited December 4, 2015 by Jayseaess

[Machpoint005]

Why WILL be have to open the windows? The only reason I open my windows in winter is to vent steam from cooking and from the bathroom when I'm taking a shower. Otherwise they all stay firmly shut in winter. I've never understood the "ventilation mantra" on this forum. In general, boats should have plenty of non-closeable fixed ventilation without needing to open windows.

 

I disagree that it isn't worth having double glazing if you can afford it. So what if the surface area of the rest of the boat is larger by orders of magnitude? The rest of the boat is insulated and single glazed windows aren't! That's like saying it's ok to scrape off a 4ft2 area of your sprayfoam because the majority of the boat it's still insulated?

 

Have a look at an occupied boat with a thermal imaging camera in winter and see where all that heat is coming out (apart from the chimney)，then you might change your mind.

 

But if you're going to install double glazed units then they should be good ones because cheap ones aren't built to flex and will allow moisture between the glazing leading to mildew.

 

Where does the OP say he'll be occupying the boat in winter?

[Naughty Cal]

 

Where does the OP say he'll be occupying the boat in winter?

In post 13.

[Machpoint005]

In post 13.

Thanks - hadn't spotted that.

[trackman]

We live aboard a lot in winter and I'd definitely have double glazed windows if specifying another boat. Plastic film "double glazing" makes a big difference to draughts & condensation on the windows but it's fiddly and messy.

 

Re 10mm glazing spacing, iirc from my physics it's not worth increasing much above that since if you do convection currents can begin to form in the gap and reduce its effectiveness. The answer is to fill the gap with a gas that transmits heat less well than air. Good panels use argon I believe. Wide gaps are better for sound insulation though.

 

Frames with a thermal break are essential, as already mentioned. Otherwise the frame causes heat loss and condensation.