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Window Openers And Mvhr


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16 replies to this topic

#1 vijay

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Posted 14 April 2016 - 03:06 PM

I've never been in a house with MVHR so I'm only used to draughty houses where it's ventilated even without opening windows.

So what I'm wondering is do you guys with MVHR use window openers as much? I'm looking at windows at the moment and wondering if I will use so many openers.

Cheers

Vijay

#2 PeterW

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Posted 14 April 2016 - 07:11 PM

Potentially not however watch out for Windows looking off balance with only one opening light, and don't forget you need means of escape in upstairs rooms

#3 Alphonsox

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Posted 14 April 2016 - 07:17 PM

+1, All windows in our house will allow egress in an emergency (Upstairs and downstairs). How often the are opened in normal use remains an unknown.

#4 declan52

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Posted 14 April 2016 - 07:58 PM

My wife opens them and I close them. All my openings have opening windows except 2.

#5 jsharris

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Posted 14 April 2016 - 08:13 PM

It's handy at this time of the year (low sun angle, cool air temperature, fair bit of solar gain) to open them. I did this afternoon, because the air cooling system turned on (it turns on at 23.5 deg C room temperature) around 16:00. At that time it was running on pure PV power, and we were still exporting, so the system was running for free, but I still thought it easier to just open a window at each end of the house and cool it down that way.

Our heating hasn't been on for several weeks now, in complete contrast to our old house, where the heating is still coming on every day. What's more, I always feel cold in the old house, and warm in the new house.

Edited by jsharris, 15 April 2016 - 06:45 AM.
lots of typos corrected................,


#6 vijay

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Posted 14 April 2016 - 09:34 PM

I'm not trying to eliminate all windows but I need to get the cos of the windows down, so wondered about how many openers I actually need/will use.

Peter, I'll keep an eye on what you said cos you're right, the windows have to look even and balanced

#7 ProDave

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Posted 14 April 2016 - 09:47 PM

When I went through the window costing exercise, I found it didn't reduce the cost much by deleting openers. The window behind the kitchen sink doesn't open as it's awkward to get at but the other kitchen windows does. A couple of the small ones don't open but otherwise most of them do.

#8 Nickfromwales

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Posted 15 April 2016 - 06:29 AM

I wouldn't be bothered about being able to not fully open some of the windows but I'd definitely want to be able to throw a child out of it in the event of a fire, eg a fanlight / other.
If you go for windows which all have a single large glazed unit, you can have some which turn and some which open from the bottom and swing out. They'd all look similar and can simply be left shut if you wish, but I'd think twice about not being able to open them at all.
Fair enough if it's one out of two windows in the same room / area but a sealed room with only the door as the exit wouldn't appeal to me one bit ( with 4 kids ).
Regards, Nick.

#9 jsharris

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Posted 15 April 2016 - 06:49 AM

Practically all our windows will open, as above there is virtually no cost difference between openers and non-openers, plus it looks mighty odd when you have fixed panes next to opening panes in some window designs, because of the difference in apparent frame thickness. The only fixed glazing we have is the glazed gable around the front door (which had to be fixed because of its shape) and a single clerestory window on the North elevation that was too high up to be worth making into an opener.

#10 notnickclegg

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Posted 15 April 2016 - 07:14 AM

We chose to have at least one opening window in every room. We also tried to put two windows in as many rooms as possible, and in many cases the second (smaller) window in such rooms doesn't open. Most of the non-openers are long, high-level windows on our neighbour's side that we wouldn't want to open anyway.

Jack

#11 Nickfromwales

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Posted 15 April 2016 - 08:37 AM

Tbh, I sometimes want to throw my kids out of the window even if there's not a fire :lol:
:ph34r:

#12 bitpipe

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Posted 15 April 2016 - 09:39 AM

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View PostNickfromwales, on 15 April 2016 - 08:37 AM, said:

Tbh, I sometimes want to throw my kids out of the window even if there's not a fire :lol:
:ph34r:

Sometimes I want to throw them out the window even when it's non opening....

#13 vijay

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Posted 15 April 2016 - 09:41 AM

Cheers guys. I'll look into this more. I need to keep the costs down but I take on board the fire escape and also the way openers will look against non openers

#14 AlexC

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Posted 15 April 2016 - 12:16 PM

Our building control asked for all habitable rooms on first floor to have emergency escape size windows as the ground floor is open plan so there is no protected means of escape separated from the kitchen. I would say you would be bonkers not being able to create some cross ventilation through the house on all levels. MVHR wont shift as much air as opening windows if you need to dump heat out of the building.

Edited by AlexC, 15 April 2016 - 12:17 PM.


#15 vijay

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Posted 15 April 2016 - 12:26 PM

As I said, not looking to eliminate window openers, just looking more closely at how many I need :)

#16 AliG

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Posted 15 April 2016 - 12:53 PM

I have at least one opening window in every room but have gone for non opening where I can.

Non opening are a little cheaper, they also have better U-Values due to the slimmer frames. My large non opening windows have sub 0.7 U-Values.

Non opening windows also don't have any hinges and openers to break and are easier to paint.

They are also more secure.

I hardly ever open a window currently and most rooms in the new place will have french doors so I don't need to be able to open windows. The architect wants some openers downstairs for cross ventilation, I am trying to eliminate as many as possible.

As mentioned if windows are next to each other you do have to be careful as the frames likely will be a different width and you will need escape windows in bedrooms.

Your decision may be influenced by how much solar gain different rooms are likely to have and whether they may need more ventilation due to overheating. Perhaps someone with MVHR can tell us how well the summer bypass works to cool things down compared to opening a window.

Edited by AliG, 15 April 2016 - 12:55 PM.


#17 stones

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Posted 16 April 2016 - 02:09 PM

We are building in what is generally acknowledged as quite a challenging climate. Non opening windows are the norm here. We are following in that tradition with a mix of opening and non opening windows, albeit every room will have one opening window to provide a secondary means of escape in the event of fire, and to provide cross ventilation in the house.

Whilst there is a small reduction in price and slightly better level of performance for the non openers, the main reason for installing non openers is that they do not have the ongoing maintenance issues (hinges, seals etc) which given the wind and salt air up here, mean a little more attention and more frequent adjustment would be required compared to more sheltered parts of the country. Why introduce a possible air leakage path when you don't have to?